Method for recovering cobalt/manganese/bromine values from residue containing used catalyst

A process for recovering valuable components of a residue from a stream of used catalyst, discharged from a plant for the liquid-phase, homogeneously catalyzed oxidation of alkylaromatic compounds under pressure, to produce polycarboxylic aromatic acids. The residue containing mainly cobalt (Co) and manganese (Mn) compounds is injected into a molten metal bath in combination with enough oxygen gas to convert essentially all carbon in the residue mainly to CO. The residue may also be sludge from a pond in which the residue is stored. The Co content of the molten metal is determined by how much of the Mn in the residue is to be rejected from the molten metal. The Mn rejected is distributed between a slag overlying the molten metal and the effluent which leaves the bath. In the slag, the Mn is trapped as manganese oxide (MnO); in the effluent Mn leaves as manganese dibromide (MnBr.sub.2). The alloy recovered is atomized to form a powder metal which is then reacted with acetic acid and hydrogen bromide to form the corresponding salts. Mn and bromine (Br) values from the slag and from the effluent are also recovered. Substantially pure Co may be recovered and exported, particularly if earthy residue from a sludge pond is processed to benefit the environment.

BACKGROUND OF THE INVENTION 
This invention relates to the recovery of cobalt (Co), manganese (Mn) and 
bromine (Br) from the residue of a catalytic process, and thereafter the 
reconstitution of catalyst from desired recovered materials. 
The problem addressed herein is as follows: An alkylaromatic polycarboxylic 
acid, e.g. isophthalic acid (IPA), terephthalic acid (TA), trimellitic 
acid (TMLA), 2,6-naphthalenedicarboxylic acid (2,6-NDA), and the like is 
produced and recovered from the product stream of a large-scale plant for 
the liquid-phase, homogeneously catalyzed oxidation of the appropriate 
precursor alkylaromatic compounds under pressure (referred to in the art 
as the "Amoco.RTM. Mid-Century.RTM. process"). The catalytic reaction is 
carried out with air in the presence of an acetic acid/water mixture which 
functions as a solvent for the reactants. The reaction generates a residue 
stream of undesired materials which entrains catalyst components. This 
residue comprises a mixture of oxygen-containing derivatives of the 
reactants and reaction products including partially oxidized and 
dealkylated oxidized mixtures of aromatic compounds, tars, and 
ring-brominated aromatic compounds, much of which residue is complexed 
with components of the catalyst used, namely Co--Mn--Br, or, 
Co--Mn--Br--Ce (cerium), or, Co--Mn--Zr (zirconium). The compounds include 
acetates, bromides and bromo-acetates of Co and Mn; a wide array of 
aromatic and polynuclear carboxylic acids, aromatic and polynuclear 
aldehydes; aromatic and polynuclear mixed carboxylic acid aldehydes, 
including ring-brominated aromatic compounds; and, unidentified Co and/or 
Mn complexes and salts of the anions of acetic acid, hydrobromic acid and 
any of the aforementioned aromatic carboxylic acids. Though the amount of 
this residue is relatively small, typically in the range from 0.1 to 25 
weight percent of the polycarboxylic acid produced, though usually less 
than about 10%, the net amount of such residue produced annually in a 
commercial plant is so large that it is desirable to recover the metal 
components, specifically the Co and Mn, and the halogen component, namely 
Br. Reference to Br hereinafter refers to bromine in compounds such as HBr 
and manganese dibromide (MnBr.sub.2), the specific form in which Br occurs 
being specified; reference to Mn refers to manganese and manganese in 
compounds such as manganese dibromide (MnBr.sub.2), the specific form in 
which Mn occurs being specified. The object is to recover these components 
from the residue. 
To date, this residue has been principally treated either by (i) 
incineration to provide flyash for further processing, namely, to recover 
its metal content, or, (ii) discharging to a residue pond notwithstanding 
the loss of the value of the Co, Mn and Br content in the resulting earthy 
residue, or the adverse environmental impact of doing so. The term 
"residue" is used hereinbelow to refer to both plant residue as well as 
earthy residue, one or the other being referred to specifically when both 
are not included. 
Referring to FIG. 1 there is schematically illustrated the main steps of a 
currently used commercial process for recovering catalyst from the 
residue. As described in U.S. Pat Nos. 4,876,386 and 4,786,621 to 
Holzhauer et al, the organic matter in the residue is destroyed by 
incineration while the catalyst components are converted to an ash. This 
ash is difficult and/or expensive to convert to reusable forms of catalyst 
for the oxidation of methyl-substituted benzenes. 
In greater detail, the residue stream is incinerated in step 2 to produce a 
mixed metal oxide flyash which is collected in step 3. Since not all the 
Co and Mn from the residue is transferred into the flyash collected, the 
remainder is lost in the incinerator's residue discharged to step 6. 
Collected flyash (from the incinerator in step 1) is washed with water in 
step 4 to remove the soluble salts and sodium bromide which are discarded 
(step 5). In the next step 7, the washed ash containing a major proportion 
(&gt;50%) by weight of Co and Mn is converted to acetates and bromides of Co 
and Mn by digestion and extraction before being returned to catalyst 
inventory (step 9). Material not extracted from the washed ash is 
discarded (step 6). Catalyst is fed from storage (9) to the process (step 
10). A portion of the catalyst from step 10 is recycled internally in step 
11, being returned to storage of catalyst in step 9 for re-use in the 
liquid-phase oxidation reactor in step 10 or directly returned to the 
process, while the desired products of the reaction are separated and sent 
elsewhere for further processing. A purge stream from step 11 generates 
the residue stream 1. This residue is then incinerated to start the 
recovery and re-use process anew. As is evident, some portion of the metal 
content of the catalyst, typically from 30% to 40%, and depending upon the 
quality of the flyash and conditions for processing it, as much as 90% of 
the residue's metal content is lost. All the Br is inevitably lost as NaBr 
from this system. 
In the process just described, the Co and Mn components not lost in step 3 
are extracted from the flyash with aqueous acetic acid and by reducing 
them with hydrazine. This is done by refluxing with a 10% hydrazine 
solution in aqueous acetic acid. This recovery process results in the loss 
of a substantial portion of the Co and Mn. Despite the economic incentive 
(a) to recover substantially all of both, main metals (Co and Mn), and 
also bromine compounds from the residue, and (b) destroy the waste organic 
content of the residue, there is no suggestion in the prior art to do so, 
much less how to do so. 
The alternative to incineration and treating flyash, namely discharging to 
a sludge pond, results over time in an earthy residue which represents a 
large recoverable accumulation of main metals Co and Mn, and the halogen 
Br in the form of bromine compounds. Discharging wastes to a pond often 
leads to contamination with earthy components, such as silica, alumina, 
clay and the like. This accumulation concurrently represents a valuable 
resource and, if recovered, would lead to restoration of a safe 
environment. I know of no single prior art process which can either, 
recover the valuable components of this earthy residue, or, those of the 
plant residue, or, those from both, together. 
The process of my invention accomplishes the recovery of valuable 
components from both residue streams, destruction of organic residues and 
segregation of earthy components by charging these streams to a properly 
constituted bath of molten metal together with the correct amount of a 
molecular oxygen containing gas. The pertinent prior art for the 
application of molten metal baths to the destruction of hazardous wastes 
is summarized as follows: 
Processes for the destruction of organic waste in a bath of molten metal, 
in the presence of oxygen, require maintaining a temperature high enough 
to convert the residue to oxides of carbon and to convert the metal 
component to a form which will dissolve in the melt. Such a melt having a 
viscosity no greater than 10 centipoise has been used to destroy toxic 
chemicals by injecting a greater than stoichiometric amount of oxygen into 
organic waste fed to the bath, as disclosed in U.S. Pat. No. 4,574,714. 
U.S. Pat. No. 4,602,574 to Bach et al teaches the destruction of toxic 
organic chemicals by injecting them, together with an excess of oxygen, 
into a melt such as is used in a steel-making plant. The high carbon, low 
ferrous oxide slag, maintained above the iron melt, provides a surface for 
exothermic radical recombination (e.g. H+Cl.fwdarw.HCl) and a medium for 
sulfur or heavy metal scavenging (see col 3, lines 49-53). 
In particular, U.S. Pat. No. 5,177,304 to Nagel teaches a method for 
converting organic waste into carbon dioxide (CO.sub.2) in a bath of 
molten metals in which the melt exists in two separate phases. In such a 
melt, metals such as iron, chromium and manganese are present in a first 
phase, and metals such as copper, nickel and cobalt are present in a 
second phase above the first phase (see col 5, lines 33-60 and col 14 
lines 14-18). To produce CO.sub.2, the '304 process requires the use of 
more oxygen than is required to produce CO. The first molten metal phase 
could be Mn or manganese oxide, while the second molten metal phase could 
be Co or cobalt oxide. It is not evident how or why the teachings of the 
'304 patent should be modified to generate Co and Mn metals and oxides 
thereof; in particular, there is no suggestion, either that the metals may 
be recovered in proportions useful for the regeneration of catalyst for 
the Mid-Century process, or, that a Co/Mn melt should be purified to yield 
substantially pure Co. 
U.S. Pat. No. 5,358,549 to Nagel et al teaches a method for converting 
inorganic waste and spent metal catalysts by directing a reducing agent, 
such as carbon, through the melt to thereby chemically reduce metal 
oxides; and the amount of reducing agent introduced is significantly in 
excess of the theoretical amount required to chemically reduce the metal 
oxide (see paragraph bridging cols 2 and 3). The improvement taught in the 
'549 patent over the prior art process, comprises using a molten metal 
bath containing a metal-containing first reducing agent which chemically 
reduces the component of the waste to form a dissolved metal-containing 
intermediate, and thereafter exposing the dissolved intermediate to a 
second reducing agent in the melt to cause the intermediate to dissolve in 
the melt for subsequent reduction of the metal component of the 
intermediate. The temperature of the melt is sufficient to cause the first 
reducing agent to chemically reduce the metal-containing component of the 
waste to form the dissolved intermediate. Co and Mn are both stated to be 
first reducing agents in the composition of the melt which is immaterial 
since it may include a solution or alloy of metals; oxides or salts, such 
as oxides or salts of the melt metals; more than one phase of molten 
metal; oxides or salts; or, elemental metal. Other first reducing agents 
identified are cadmium (Cd) chromium (Cr), copper (Cu), iron (Fe), 
potassium (K), molybdenum (Mo), sodium (Na), nickel (Ni), lead (Pb), 
sulfur (S), tin (Sn), tungsten (W) and zinc (Zn) (see paragraph bridging 
col 5, line 63 to col 6, line 10; and col 13, lines 28-33). After 
formation of the dissolved intermediate, the second reducing agent 
chemically reduces the metal of the dissolved intermediate at a rate 
sufficient to cause essentially all the dissolved intermediate formed to 
dissolve in the melt. (see col 2, lines 30-46). 
Reference to using a melt of the metal to be recovered in the bath is found 
in the '549 patent where it states: "Metal recovery of non-volatile metals 
may be particularly advantageous in this invention where the principal 
metal of the waste, the first metal oxide, is the same as the bath metal, 
thereby affording a bath enriched in a recoverable metal. For example, 
molten copper can be employed as the bath metal for recovery of copper 
metal from waste streams highly enriched in the oxides of copper. In those 
cases where the free energy of formation of the oxide of the bath metal is 
higher than that of a metal contaminant present in the waste, it may be 
advantageous to use a sacrificial metal with a highly negative free energy 
of oxidation, relative to the first metal oxide." (see col 12, lines 
38-50). No mention is made of recovering metals in an oxidizing 
environment. 
The use of a molten bath in the prior art is based on choosing its physical 
properties to provide a desirable reaction medium for an oxidation or 
reduction reaction. While the scientific principles governing the 
conversion of organic waste into CO.sub.2, CO, H.sub.2 and water, in a 
melt of certain metals are known, there is no motivation or suggestion in 
the prior art to maintain a bath of molten Co for any useful purpose. One 
would not be led to choose such a bath for the disproportionation of the 
residue Co-containing organic compounds, or, Mn-containing organic 
compounds, or a mixture of both, for the specific purpose of recovering 
either or both metal components. There is no motivation to choose a 
de-watered residue containing Co and Mn compounds, obtained from the 
Mid-Century process, and react it with oxygen in a molten alloy of the 
same metals to regenerate the alloy. Nor is there any suggestion in the 
prior art that the ratio of Co and Mn metals in the alloy recovered may be 
controlled by temperature and/or the amount of oxygen used; nor that Mn 
should deliberately be rejected to slag from which it is recoverable as 
opposed to used as a ceramic. 
Moreover, in all known processes for the recovery of reusable Co and Mn 
from a catalyst used in the Mid-Century process, a significant if not 
substantial portion of the Co, Mn and Br values of the catalyst in the 
residue is lost. And no process recovers both the process residues and the 
earthy residues. 
The process of this invention is uniquely well suited to recover 
essentially all of the Co, Mn and Br values in both of these residue 
streams. By "essentially all" is meant that in excess of 90%, typically 
more than 95%, and preferably in excess of 99% of any one of the 
components (in this particular context) may be recovered. The process may 
be operated either to re-manufacture a catalyst at the same ratio as the 
incoming residue, or, at a different ratio suitable for catalyst, or, to 
purify a Co/Mn molten alloy ("melt") to produce substantially pure Co. By 
"incoming residue" is meant a single stream from a given Mid-Century 
process plant, or the combination of multiple streams from plants 
producing the same or different product, or streams of earthy residues, or 
streams of earthy residues and plant residue streams. By "substantially 
pure Co" is meant that the molten Co recovered is at least 90% pure with 
Ce, Zr and C contaminants, and for purposes of this disclosure is regarded 
as an alloy of Co/Mn containing less than 10 parts Mn per 100 parts 
(Co+Mn) by wt. Typically recovered Co is 95.sup.+ % pure, and most 
preferably, for export, is 99.sup.+ % pure with only trace contaminants. 
In each case, the proportion of Mn separated from molten Co is controlled 
by means of temperature together with a required amount of molecular 
oxygen-containing gas, preferably oxygen. Doing so, not only ensures the 
recovery of either Co/Mn melt having a desired ratio, or substantially 
pure Co, but also the recovery of essentially all the Mn and Br values. 
A further advantage of this invention is that much equipment already 
existing in a facility for the recovery of Co and Mn values from flyash 
may be used to reformulate catalyst from the products of the present 
invention, thus decreasing costs. 
SUMMARY OF THE INVENTION 
It has been discovered that the composition of a non-ferrous melt of Co/Mn 
alloy generated from residue may be controlled by temperature in 
combination with an amount of oxygen chosen relative to the carbon content 
of the residue, both oxygen and residue being contacted with the molten 
alloy. 
The foregoing discovery provides a solution to the problem of recovering 
essentially all, if desired, the cobalt (Co), manganese (Mn) and also 
bromine (Br) as HBr or MnBr.sub.2 from residue of commercial and 
environmental significance, purged as a waste stream from a process for 
the oxidation of alkylaromatic. 
More specifically, it has been discovered that a residue of used 
bromine-containing catalyst in the form of waste bromine-containing 
organic compounds in which Co and Mn are complexed with products and 
by-products of the Mid-Century process, may be reacted in a thermochemical 
reaction zone ("reactor") with oxygen, in a bath of molten Co/Mn alloy, to 
destroy the organics and regenerate Co/Mn alloy without adding a reducing 
agent or any additional organic carbonaceous matter, to recover 
essentially all the Co, Mn and Br values. 
Cobalt is recovered essentially completely in the form of molten metal 
withdrawn periodically from the reactor either pure or as a manganese 
alloy. Cobalt is readily converted to catalyst component by reaction with 
and dissolving in acetic acid. 
Manganese is recovered in three different streams. Like cobalt it is 
recovered in the form of molten metal alloy periodically withdrawn from 
the reactor. Mn withdrawn as metal alloy may readily be converted to 
catalyst by reaction with and dissolving in acetic acid. Mn in the residue 
may be either partially, or essentially completely rejected to a slag of 
MnO formed above the melt, and/or as manganese bromide (MnBr.sub.2) in a 
gaseous effluent from the reactor. MnO is readily extracted from the slag 
as manganese acetate or bromide which is conventionally reformulated with 
acetates and bromides of Co/Mn to replenish fresh catalyst. MnBr.sub.2 is 
readily recovered from the effluent gas stream. MnBr.sub.2 is a catalyst 
component itself. Combining these three streams leads to essentially 
quantitative recovery of Mn. 
Bromine values are essentially completely rejected from the melt. By 
"essentially completely rejected" is meant that in excess of 99% of the 
bromine is driven from the melt. Liberated HBr and manganese dibromide, 
and other metal bromides, if present, leave in the effluent. These 
products are collected in an aqueous scrubber and are directly useable to 
prepare catalyst by combining in proper amounts with the other process 
streams generated, thus recovering the bromine component. 
The gaseous effluent of the process after recovery of Br values, contains 
CO and hydrogen together with small amounts of water and carbon dioxide 
depending on the exact conditions of operation. These effluents are used 
either for fuel value or for the synthesis of organic compounds. 
It is therefore a general object of this invention to convert residue, 
either into an alloy of Co and Mn, or into substantially pure Co, either 
substantially continuously or batch-wise, by reacting the residue with a 
controlled amount of oxygen in a molten bath consisting essentially of 
Co/Mn, Co/Mn/MnO or Co/MnO alloy, and vitreous slag. The bath is 
maintained in a reactor at a temperature above the melting point of the 
alloy but below its boiling point. The molten alloy contains essentially 
no contaminant oxides of Mn. The oxides of Mn reside essentially 
completely in an overlying slag layer. The actual stoichiometric amount of 
oxygen is that required to be used to convert all incoming carbon into 
carbon monoxide, and to convert Mn to MnO in the amount desired, with 
essentially no conversion of Co to cobalt oxide (Co) at a given 
temperature. By "essentially no conversion to CoO" is meant that less than 
1% by wt of the combined Co and Mn in the residue is converted to cobalt 
oxide. By "essentially no contaminant metals" is meant that such metals as 
zirconium (Zr), and cerium (Ce) may be present in an amount less than 1 
part per 100 parts by wt of the alloy, the Zr and Ce being essentially 
completely rejected into the slag as oxides. Typically Co is present in 
the molten Co/Mn alloy in an amount in the range from 5 parts to about 50 
parts Co per 100 parts by weight of Co/Mn alloy, and the contaminants in 
the alloy include Ce, Zr and carbon (C), each contaminant present in an 
amount less than 1 part by weight. 
It is a specific object of this invention to provide a process for 
recovering the Co and Mn metals in the residue, substantially 
quantitatively, provided Mn present in the slag, as well as that present 
in the gaseous effluent from the reactor are recovered. When Mn thus 
recovered is used to reformulate catalyst, the Co/Mn ratio of the catalyst 
may be essentially the same as that present in the residue fed to the 
reactor, if so desired. 
It is still another specific object of this invention to provide a process 
for recovering substantially pure Co, substantially quantitatively and 
reject all Mn from the melt. 
It is yet another specific object of this invention to provide a process 
for recovering essentially all the Br values in the residue. 
It is also a specific object of this invention to provide a process with a 
unique benefit, namely, facilitating the economical recovery of the 
valuable main metals from earthy residue dredged from sludge ponds while 
restoring the environment. Bromine values may also be recovered from the 
earthy residue irrespective of whether plant residue is being processed. 
Since the Co, Mn and Br compounds recovered from added earthy residue will 
be in excess over that required to replenish depleted catalyst from a 
process generating plant residue, the excess Co, Mn and Br compounds may 
be used for other purposes.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
FIG. 2 schematically illustrates the main steps of a preferred embodiment 
of the novel process in which residue is collected and de-watered in step 
1, then fed, along with a molecular oxygen-containing gas, preferably 
oxygen, from a source of oxygen 2, to a thermochemical reaction zone in 
which a reactor contains molten Co/Mn alloy (step 3). Residue is added to 
the melt and converted in the presence of the oxygen, to molten alloy and 
a slag layer of vitreous matter which floats on the surface of the melt 
(step 8). Vapors leaving the reactor as effluent gas include CO, H.sub.2, 
and bromine-containing matter, mainly HBr and MnBr.sub.2. The bromine 
containing components are collected in a scrubber or other device in step 
4. Effluent from the scrubber consists essentially of CO and H.sub.2 which 
are ducted away to step 5 where they are used for their fuel value, or for 
some other economically desirable purpose. 
Molten alloy is withdrawn from the bath 3 and atomized to form a powder of 
the alloy which is collected in step 6 as a fine alloy powder. By 
"atomized" is meant that the melt is comminuted, typically by quenching 
with water, to a metal powder, having primary particles in the size range 
from about 1 .mu.m to 500 .mu.m. The `powder metal` is then reacted with 
aqueous acetic acid, or hydrobromic acid, separately or combined, or 
combined with the products of bromine value recovery (step 4). The desired 
composition of re-manufactured Co/Mn catalyst may also be adjusted by 
addition of MnO recovered from the vitreous slag, or Mn(OAc).sub.2 or 
MnBr.sub.2 solution prepared from the MnO slag in step 8. Re-manufactured 
catalyst is stored in step 9, preferably after filtering to remove 
insoluble materials including particles of unreacted alloy or carbon. 
Stored catalyst is fed, as required, to the reactor in the Mid-Century 
process in step 10 to synthesize the desired reaction product. The product 
is then recovered by conventional means, returning a portion of the 
catalyst to the process with an internal recycle in step 11, and purging a 
portion to a residue stream. A portion of the internally recycled catalyst 
may be returned to storage in step 9, and the residue is discharged to 
step 1 where the process is started anew. The process details and 
equipment used in the loop formed by steps 9, 10 and 11 which result in 
the discharge of the residue in step 11 and from distillation of the 
desired carboxylic acid, are all well known and set forth in one or more 
patents relating to the Mid-Century process. Some U.S. Pat. Nos. 
references are 4,162,991; 4,266,084; 4,311,521; 4,794,195; 4,876,385; 
4,876,386; 5,081,290; and 5,181,290; and, the specific disclosures thereof 
relating to the process operating conditions which generate recoverable 
residue, are incorporated by reference thereto as if fully set forth 
herein. 
Referring to FIG. 3 there is schematically illustrated the processing of 
earthy residue in conjunction with plant residue. In addition to the 
process steps 1 through 8 described above in FIG. 2, earthy residue is 
processed along with plant residue as follows: Earthy residue is dredged 
from a sludge pond, dried in driers at 12, and the dried earthy residue 
fed to the reactor at 3 with oxygen from 2. Optionally, earthy residue may 
be combined with plant residue before drying both in step 1. 
Accordingly, dried earthy residue from step 12 is fed to the reaction zone 
in step 3 and Br compounds recovered by scrubbing with any desired 
absorbent in step 4. As before, the CO and H.sub.2 may be recovered for 
use in step 5. The build-up of alloy is prevented by withdrawing melt from 
the bath in step 13. As before, essentially pure Co may be withdrawn at 14 
if an essentially pure cobalt melt is used in the reactor and excess 
oxygen is added to convert essentially all Mn in the residue which is not 
driven off as MnBr.sub.2 vapor, to MnO which is withdrawn as a slag. 
Components such as silica, alumina and Magnesium oxide are also withdrawn 
as slag. 
As before, HBr and MnBr.sub.2 are recovered in step 4. If no more catalyst 
for storage is required, then excess Co/Mn alloy is withdrawn in step 13 
for export, either as ingots of alloy or as powder alloy. If essentially 
pure Co is to be recovered in 14, then flow of oxygen is adjusted to 
convert all Mn in the melt to MnO, thus removing Mn from the melt as MnO. 
The MnO is rejected to the slag which is removed at 15. 
Residue is also conventionally obtained in step 1 after the reaction 
product from step 10 is distilled. This residue, along with residue 
obtained from the internal catalyst recycle in step 11, is fed in step 3, 
into the molten alloy bath in a reactor schematically illustrated in FIG. 
4, and referred to generally by reference numeral 20. The reactor 20 is a 
cylindrical induction furnace having a steel body 23 with induction coils 
21 built into 75% alumina refractory-lined walls 22 of the reactor which 
is provided with a water-cooled gated slag discharge spout 33 equipped 
with a tightly fitting gate 38 which is opened periodically to discharge 
liquid slag 40. Preferably, mullite fiber insulation is packed between the 
outer surface of the refractory walls 22 and the inner surface of the 
steel body 23 of the reactor. Molten alloy 30 is held in the lower portion 
of the reactor; the level of the melt is preferably maintained below the 
slag discharge spout 33. The lower portion of the reactor preferably rests 
on a 95% magnesite ramming mix 27 which is packed between the lower steel 
outer surface of the reactor and a supporting structure of chromic 
oxide-alumina bonded 90% super-duty firebrick 28. 
Hot gases from the reactor are led through an effluent discharge nozzle 24 
through a pressure lock to a water scrubber (not shown). To feed the 
reactor 20, residue is led into it through the tuyere 25 through which 
residue mixed with oxygen is introduced into melt 30. If desired, oxygen 
may also be injected into the molten alloy bath through a separate 
conduit. An over-accumulation of molten alloy is prevented by withdrawing 
a portion through the molten alloy taphole 29. 
Characterization of Plant and Earthy Residues, and Pretreatment thereof: 
Residue may contain in the range from about 0.01% to about 45% by weight 
(wt) of Co and Mn combined, on a water-free basis, typically from about 2% 
to 10% by wt, and includes small quantities of other metals, particularly 
Ce and Zr, each typically present in an amount less than 1% by wt of dry 
residue, and other metals added deliberately as either catalyst promoters 
or unavoidably present as corrosion products. By "dry residue" is meant 
that the moisture content is less than 1% by wt. Typically, Co and Mn are 
together present in the residue in an amount in the range from 0.1% to 
about 20% by weight, on a water-free basis, and the residue is free of 
metal sulfides, phosphides or nitrides. Mn typically predominates in the 
residue, the weight ratio of Mn/Co being as much as 5:1, though in some 
instances Co predominates being in the range from about 1:1 to about 1:5. 
Plant residue contains a mixture of components. For illustrative purposes, 
a composition of residue drawn from the patent literature is shown in 
table 1. It is understood that the specific residues will vary with the 
feeds and process conditions and the process of this invention is in no 
way limited by this particular example of residue composition. 
TABLE 1 
______________________________________ 
Residue of terephthalic acid manufacture on 
acetic acid and water free basis: 
Component Wt % 
______________________________________ 
Phthalic Acids 19.7 
Benzoic Acid 14.8 
Toluic Acids 26.8 
Methyl Phthalic Acids 
2.6 
Trimellitic and Trimesic Acids 
4.3 
4-Carboxybenzaldehyde 
9.1 
Tolualdehyde 0.4 
Benzaldehyde 0.004 
Terephthaldehyde 0.2 
Methylbenzyl acetate 0.02 
Formyl Acetate 0.1 
Benzyl Benzoate 0.07 
Phthalide 2 
Co-Products 4.2 
Cobalt Acetate 4.5 
Manganese Acetate 8 
Bromine 2.2 
Iron 0.09 
Sodium 0.3 
Trace Metals 0.02 
______________________________________ 
Preferably, this residue is dried to remove water prior to injection into 
the molten Co/Mn or Co bath. The preference for a dried feed is economic, 
in that there is a cost penalty attached to heating water. 
The components of earthy residues from sludge ponds are similar in 
composition to the plant residues from which they come, except for the 
contribution of the earth, if the pond is not lined, or the liner is 
damaged. Sludges will vary widely in composition depending on the age of 
the plant, the time the residue is held in the pond and any treatments to 
which the pond water or process effluent stream is subjected. The earthy 
residue will also contain biomass of varying composition and in general, 
fewer of the organic components described in Table 1. In addition, clays, 
binders, floculants and settling agents may also be present, these being 
determined by local conditions. Unlike other competing processes, recovery 
of Co and Mn in the process of this invention is largely insensitive to 
the additional contaminants introduced by clays, binders and floculants. 
Typical impurities introduced are SiO.sub.2, Al.sub.2 O.sub.3, MgO, and Fe 
in the forms they may be present in clays, binders and floculants. 
SiO.sub.2, Al.sub.2 O.sub.3, and MgO will all partition to the slag under 
the reaction conditions of this process. 
Although not critical to this invention, it is preferable that the sludge 
be dried before addition to molten bath. Drying may take place separately 
from the plant residue stream, or the streams may be consolidated and 
dried. 
The Nature of the Melt and Operating Conditions: 
To operate the process, the reactor is charged with any convenient form of 
Co and Mn metals in proportions to produce a Co/Mn alloy having about the 
same ratio of Co:Mn as is expected to be formed when the melt reaches 
equilibrium with a feed of residue from the Mid-Century process. The 
desired ratio of Co/Mn in the molten alloy is obtained by rejecting a 
desired amount of Mn (i) as manganese oxide (MnO) to slag overlying the 
alloy; and (ii) into an effluent from the bath, the amount of Mn rejected 
being sufficient to yield an alloy containing Mn in the range from about 
0.01 part to about 500 parts per 100 parts (Co+Mn) in the alloy. The 
initial heating of the charge is effected by the induction coils. 
Alternatively, a hot charge may be generated by any other suitable means 
such as in an electric arc furnace from which molten alloy is transferred 
to the reactor. 
Once the charge is melted and reaches a temperature above the melting point 
of the Co/Mn alloy to be formed, residue in combination with oxygen gas is 
injected into the melt. The temperature of the melt is allowed to increase 
until the desired temperature of the melt in the operating range from 
about 1245.degree. C. to about 2500.degree. C., preferably from 
1500.degree. C. to 2350.degree. C., is reached. No additional carbonaceous 
matter is required to be added to the residue to satisfy the chemical 
needs of the thermochemical reaction. 
The heat energy in the molten alloy incites disproportionation of the 
organic moieties in the residue, converting them to CO and H.sub.2 while 
the Br is liberated mainly as HBr and MnBr.sub.2 gases. 
The thermochemical reaction may be either exothermic, endothermic, or 
neutral, depending upon the amount and composition of the carbonaceous 
matter in the residue, when a typical water-free residue is fed to the 
reactor, and the amount of oxygen. If endothermic, additional heat 
required to maintain the temperature of the bath may be supplied by 
electricity in the induction coils, or by introducing a fuel directly in 
the bath for the sole purpose of maintaining its temperature. Such fuel 
may be provided with natural gas, propane or any other sources of heat 
energy from other plant vent or waste streams (such as brominated organic 
compounds derived from vent streams) which are less expensive than 
electricity, and are unrelated to and independent of the chemical 
conversion of residue into Co, Mn and Br compounds. 
Once the reactor is in operation, a wide range of ratios of Mn/Co may be 
fed in the residue without sacrificing the ability to tailor the ratio of 
Mn/Co in the molten bath. If the bath is found to have a higher Mn content 
than is desired, excess oxygen is used to remove as much Mn as is 
necessary. On the other hand, while normally there is no reason to 
increase the Mn content of the bath relative to the Co present, it may be 
done by adding MnO or Mn metal to the residue. 
It is critical that the molten metal in which the residue is to be 
converted to substantially pure Co, be substantially pure Co above 
1495.degree. C., preferably from 1500.degree. C. to 2500.degree. C.; thus, 
in excess of 90% pure Co, and as high as 99.99% pure Co, based on Co/Mn 
content, is recovered. When the molten metal to be recovered is alloy in 
the range from about 1/4 to 9/1 based on Co/Mn content, the molten metal 
is Co/Mn alloy above 1245.degree. C., preferably from 1500.degree. C. to 
2350.degree. C. Thus, depending upon the metal to be withdrawn, the Co/Mn 
content of the molten metal may range from about 1/4 to 9999/1. Typically, 
both Co and Mn are replenished in the bath when sufficient oxygen is fed 
to convert the residue to CO, H.sub.2, HBr, and metal bromides which leave 
the bath in the vapor phase, but without forming oxides of Co in the 
molten metal, and such oxides of Mn as are formed are rejected to the 
slag. A Co/Mn alloy containing essentially no bromine compounds, is 
recovered for reuse. The Co/Mn alloy most typically withdrawn has a ratio 
of Co/Mn is in the range from about 1:1 to about 1:3. 
To recover Co and Mn in an alloy in which the ratio of Co/Mn is the same 
ratio as that in the residue fed to the molten bath, it is not only 
essential that an actual stoichiometric amount of oxygen be used, but also 
that MnBr.sub.2 be recovered from the effluent. If desired, substantially 
pure cobalt may be recovered as described below. 
Since the carbonaceous content of plant residue is converted mainly to 
carbon monoxide and hydrogen and the residue contains less than 1% by wt 
of metals other than Co and Mn, accumulation of slag is slow except when 
conditions are deliberately chosen to reject all or part of the Mn in the 
residue into the slag layer. Accumulation of slag is expected when earthy 
residue is used. 
The reactor may be operated under either atmospheric, or superatmospheric 
pressure in the range from more than 1 up to about 20 bar (atmospheres), 
preferably in the range from 1 to 10 bar, the reactor being designed and 
constructed to operate under the conditions chosen. 
The reaction is run under conditions whereby the reactants are exposed to 
process conditions for sufficient time to ensure complete reaction. A 
numerical criterion for such time is defined as the rate at which cobalt 
is added divided by the total mass of the metal phase of melt. This 
measure corresponds to the standard definition of "weight hourly space 
velocity" and is hereafter referred to as WHSV. Suitable ranges of 
operating conditions are in the range from 0.1 hr.sup.-1 to 
1.times.10.sup.-5 hr.sup.-1, preferably in the range from about 10.sup.-2 
hr.sup.-1 to about 10.sup.-4 hr.sup.-1. 
Stoichiometry: 
Temperature and oxygen feed rates may be used to control the chemical 
composition of the bath and effluent. If, as is generally desired, low 
carbon levels in the melt are to be obtained, higher temperatures are 
preferred, as are higher amounts of oxygen. If all the Mn fed is to be 
retained in either the melt or as vapor phase MnBr.sub.2 then some carbon, 
in the range from 0.1% to 5% by weight, typically 0.5% to 2%, is allowed 
to build up in the metal alloy. If 95+% purity Co is to be removed from 
the molten phase, then sufficient oxygen is used to drive the reaction to 
achieve that purity. Since all desired materials can be recovered 
irrespective of their distribution in the molten alloy, slag and effluent 
vapor, the choice of operating conditions and subsequent product 
distribution is a matter of local economic preference. 
The stoichiometry of oxygen addition takes into account the above 
considerations and balances other needs as well. The stoichiometric amount 
of oxygen is the amount of oxygen that is required to convert all carbon 
present to carbon monoxide only. This stoichiometric amount of oxygen does 
not include oxygen used to convert carbon to carbon dioxide, or, to 
convert metal to metal oxide, or, to convert hydrogen to water. 
This stoichiometric amount of oxygen takes into consideration oxygen, or 
oxygen equivalents, in the incoming residue. The amount of divalent metals 
introduced into the bath, except those which leave the system in the vapor 
phase as bromide compounds, count as oxygen equivalents. The organic 
residues of the Mid-Century process typically contain a large amount of 
oxygen, the carbon to oxygen (C/O) ratio being in the range from 8/4 
(single ring) to 14/1 (fused rings); e.g. benzaldehyde is 7/1; benzoic 
acid is 7/2; methylnaphthaldehyde. The C/O ratio in earthy residues will 
vary widely, depending upon the source of each, and are to be accounted 
for. 
If it is desired to recover Co/Mn alloy with a ratio different from that of 
Co/Mn in the residue fed, part or all of the manganese may be removed 
provided the amount of oxygen is increased sufficiently to react with the 
amount of Mn to be rejected as MnO. 
Finally, if additional fuel is used solely to maintain temperature in an 
otherwise endothermic system, then its carbon and oxygen content is also 
to be accounted for. 
The stoichiometric oxygen required may be expressed in the following 
equation: 
EQU Moles O.sub.2 gas to be added={C.sub.tot --O.sub.tot +Mn.sub.ox --Co.sup.+2 
--Mn.sup.+2 }/2 
where 
C.sub.tot =total moles of carbon fed, including any carbon in added fuel; 
O.sub.tot =total atom equivalents of oxygen in the feed; 
Mn.sub.ox =moles of Mn to be rejected as oxide; 
Co.sup.+2 =divalent Co in the residue; and, 
Mn.sup.+2 =divalent Mn in the residue to be retained in the bath and not 
rejected as either MnO or MnBr.sub.2 in the vapor phase. 
Reactor Design and Construction: 
The design and construction of a suitable reactor for use in this process 
is disclosed in U.S. Pat. Nos. 5,191,154; 5,301,620; 5,358,697; 5,396,850; 
5,433,572; 5,435,982; 5,436,210, and 5,491,279 and in references cited 
therein, which patents are incorporated by reference thereto as if fully 
set forth herein. The design and construction of a reactor to carry out 
the claimed process forms no part of this invention. 
Integration into an Existing Mid-Century Plant: 
This process offers numerous opportunities for integration into existing 
plant operations, both supplying and consuming waste heat through heat 
exchange, and offering CO+H.sub.2 as either fuel for heat recovery, or, 
for a synthesis gas ("syn gas") feed for chemical reactions. Integration 
of this invention into the general operation of an aromatic oxidation 
plant is within the skill of engineers who design and construct chemical 
plants. 
Recovery and Application of Materials from the Molten Bath: 
Catalyst is re-manufactured by first atomizing the molten metal to produce 
a powder metal then reacting the powder metal with glacial or aqueous 
acetic acid or (glacial or aqueous) acetic acid/hydrobromic acid mixtures, 
or appropriate acidic streams containing manganese dibromide, or any 
combinations of the foregoing, at a temperature in the range from 
80.degree. to 200.degree. C. to produce the metal acetates. HBr may be 
added in the amount desired. 
Numerous methods for production of powders of metals are taught in 
"Atomization of Melts" by Andrew J. Yule and John J. Dudley published by 
Oxford Science Publications, Oxford, England. The powder metal is 
preferably produced with a metal powder generating system marketed by 
Atomising Systems Limited, Sheffield, England. An alternative is to 
recover the alloy in the form of ingots of Co/Mn alloy or pure cobalt, 
particularly if earthy residue is being processed for export, or as solid 
particulate free metal, obtained directly from the melt. 
Recovery of MnO from the slag: 
Irrespective of how slag is tapped, either periodically or continuously, 
the MnO is recoverd by conventional leaching. The liquid slag is 
comminuted to produce a powder slag by any conventional means, preferably 
by atomization, in a process analogous to that for atomizing molten alloy. 
The powder slag preferably has an average particle diameter in the range 
from 1 .mu.m to about 500 .mu.m. Acidic leaching of the powder is effected 
by contacting it with either HBr or acetic acid under conditions which 
produce the corresponding salts; basic leaching is effected with ammonium 
hydroxide. 
Recovery of Mn and Br values from the Vapor Phase which contains "Syn Gas": 
The Br and Mn values transported in the vapor phase are preferably 
recovered by any conventional unit operations for removing materials from 
the vapor phase. Such unit operations include condensation, desublimation, 
quenching and scrubbing the effluent gas with water, or dilute acetic acid 
or hydrobromic acid. A scrubber will typically be operated in a 
recirculating mode resulting in a scrubbing solution approaching 
equilibrium concentrations of MnBr.sub.2 and HBr. These operations may be 
carried out under atmospheric or superatmospheric conditions up to 20 bar, 
and elevated temperature up to 250.degree. C., such as are optimum for 
such processes. Volumes and purge rates of such a system will be chosen to 
facilitate recombination of the streams at desired catalyst concentrations 
in the range from about 1 to 20% by wt of metal. 
Depending upon the desired portion of Mn to be retained in the molten 
alloy, the amount of Mn discharged into the slag as MnO and into the 
effluent as MnBr.sub.2, will vary from 0.01 part to 99.99 parts of Mn per 
100 parts of Co/Mn alloy. Essentially all the MnBr.sub.2 in the effluent 
is recovered, preferably quantitatively, and combined with Mn values 
recovered in the slag. 
The thermal energy (BTU content) of the remaining effluent gases, namely CO 
and H.sub.2 (syn gas) after the bromine content is removed may be 
recovered by employing a conventional gas-fed boiler. The energy content 
may also be converted directly to electricity by a device such as a fuel 
cell. If the syn gas is sufficiently free from deleterious impurities, it 
may be used as feed for the synthesis of numerous chemical compounds, 
typically methanol and acetic acid. 
Catalyst Reconstitution: 
The primary source of material to reconstitute catalyst is the molten metal 
withdrawn from the bath. It is preferred to reduce the size of solid metal 
particles as disclosed above, to facilitate conversion to metal salt at a 
relatively lower temperature and pressure than would be required with 
larger particles, because of the higher surface area of the smaller 
particles. While the active catalyst is generally considered as a mixture 
of Co/Mn and HBr or bromide salts, and may be returned as such, the 
bromine value recovered may be managed separately. In these cases the 
reconstituted catalyst will consist essentially of Co and Mn acetates. 
Excess Recovery: 
Since Co, Mn and Br values derived from earthy residue may be in excess of 
that required for catalyst to be immediately re-used, such excess may be 
used to re-manufacture catalyst for storage. Thus, it will now be evident 
that processing of plant residue may proceed as usual, and earthy residue 
may be processed as the need for products for export from the plant 
arises, or, may be processed to clean up the sludge pond site. 
Where earthy residue is to be processed unrelated to the re-manufacture of 
catalyst for the plant, it is necessary to practice only the essential 
steps to recover the economically valuable components of the earthy 
residue. 
Illustrative Examples: 
For the residues treated in the following illustrative examples, the 
average molecular composition corresponds approximately to benzoic acid 
(C.sub.7 H.sub.6 O.sub.2). The residue herein consists essentially of 
acetates of Co and Mn, and HBr, the remaining organics being expressed as 
benzoic acid. Designations of "moles" refers to kilogram-moles (KgMoles). 
The percent by weight of Br and Co in the residue fed to the reactor, is 
maintained the same in each of the examples below, as is the reactor 
pressure of 10 atm. In each case, the recovered melt of metal is atomized 
and converted to re-manufactured catalyst. 
EXAMPLE 1 
Ratio of Co/Mn=1/1 in residue fed; ratio of Co/Mn=1/1 in re-manufactured 
catalyst; Mn in the re-manufactured catalyst is recovered from the alloy 
melt, the MnBr from the scrubber and the MnO from the slag. 
A bath of Co/Mn/MnO/C (609/325/37/29) containing 1000 Kg of molten metal 
and slag is maintained at the given equilibrium composition at 
2200.degree. C. under 10 atm pressure in the reactor. Essentially all the 
MnO is present in the slag which forms an immiscible layer above the Co/Mn 
alloy. 292 Kg/hr of dry plant residue containing 2% Co, 2% Mn and 4% Br by 
wt, is injected into the molten alloy with oxygen. The WHSV based on Co is 
0.0658 hr.sup.-1. The equivalent rates of feed (moles/hr) are as follows: 
C=14.83; O=4.82 (contained in the residue); Co=0.099; and Mn=0.054 
(remaining Mn introduced with the residue is in the slag as MnO, or, 
leaves in the reactor's effluent as MnBr.sub.2). The amount of oxygen 
injected is about 157.9 Kg/hr (4.93 KgMoles) and effluent from the reactor 
is led to a water scrubber. During operation at equilibrium, about 70.4 Kg 
of molten alloy are withdrawn every 8 hr, and atomized to yield a powder 
having an average particle diameter of 100 .mu.m, using a high pressure 
water stream. The composition of the particles is essentially the same as 
that of the melt beneath the slag. 
During the same 8 hour period, 1040L (liters) of scrubber water are 
collected containing 76.2 Kg of MnBr.sub.2 and 36.6 Kg of HBr. MnO 
accumulates in the slag at a rate of about 0.35 Kg/hr. Slag levels are 
adjusted by periodic withdrawals, and the slag withdrawn is atomized to 
100 .mu.m with a stream of water under high pressure. 
The 70.4 Kg of atomized metal, 1040L of scrubber water and 119 Kg of 
glacial HOAc (acetic acid) are combined in a vented heated vessel, and the 
temperature raised to 90.degree. C., resulting in a solution of mixed 
acetates and bromides of Co and Mn in which solution Co and Mn are 4.1% 
and 3.8% by wt, respectively. There is essentially no free acid. In an 
analogous manner, the atomized slag is digested with HOAc at 90.degree. C. 
to yield a solution of Mn(OAc).sub.2. The desired Mn level in the 
re-manufactured catalyst is adjusted to Co/Mn=1/1 by addition of the 
required amount of this Mn(OAc).sub.2. The re-manufactured catalyst is 
filtered to remove suspended carbon in the alloy. 
EXAMPLE 2 
Ratio of Co/Mn=1/2 in residue fed; ratio of Co/Mn=1/1 in re-manufactured 
catalyst; Mn not wanted in the melt is rejected as MnO in slag by using 
enough oxygen to form the MnO. 
A bath of Co/Mn/MnO/C (341/194/463/1.4) containing 1000 Kg of molten metal 
and slag is maintained at the given equilibrium composition at 
2200.degree. C. under 10 atm pressure in the reactor. Essentially all the 
MnO is present in the slag which forms an immiscible layer above the Co/Mn 
alloy. 292 Kg/hr of dry plant residue containing 2% Co, 4% Mn and 4% Br by 
wt, is injected into the molten alloy with oxygen. The WHSV based on Co is 
0.01075 hr.sup.-1. The equivalent rates of feed (moles/hr) are as follows: 
C=14.2; O=4.95; Co=0.099; and Mn=0.06 (remaining Mn is in the slag, or, 
leaves the reactor in the effluent). The amount of oxygen injected is 
about 150.3 Kg/hr (4.7 KgMoles) and effluent from the reactor is led to a 
water scrubber. During operation at equilibrium, about 73.1 Kg of molten 
alloy are withdrawn every 8 hr, and atomized to form a powder metal as in 
Example 1 above. The composition of the particles is essentially the same 
as that of the melt beneath the slag. 
During the same 8 hour period, 1040L of scrubber water are collected 
containing 69.3 Kg of MnBr.sub.2 and 41.2 Kg of HBr. MnO accumulates in 
the slag at a rate of about 7.9 Kg/hr. Slag levels are adjusted by 
periodic withdrawals, and the slag withdrawn is atomized to 100 .mu.m with 
a stream of water under high pressure. 
The 73.1 Kg of atomized metal, 1040L of scrubber water and 122 Kg of 
glacial HOAc are combined in a vented heated vessel, and the temperature 
raised to 90.degree. C., resulting in a solution of mixed acetates and 
bromides of Co and Mn in which solution Co and Mn are 4.1% and 3.9% by wt, 
respectively. There is essentially no free acid. As in Example 1 above, if 
necessary, slag is digested with HOAc to yield a solution of Mn(OAc).sub.2 
and as much of this solution as necessary is added to provide the desired 
1/1 ratio of Co/Mn in the re-manufactured catalyst. Also as before, 
re-manufactured catalyst is filtered to remove suspended carbon in the 
alloy. 
EXAMPLE 3 
Recovery of substantially pure Co; ratio of Co/Mn=1/2 in residue fed. 
Essentially all Mn is rejected to slag by using enough oxygen. 
A bath of Co/Mn/MnO/C (548/11/424/17) containing 1000 Kg of molten metal 
and slag is maintained at the given equilibrium composition at 
1500.degree. C. under 10 atm pressure in the reactor. Essentially all the 
MnO is rejected to slag which forms an immiscible layer above the molten 
metal. 292 Kg/hr of dry plant residue containing 2% Co, 2% Mn and 4% Br by 
wt, is injected into the molten alloy with oxygen. The WHSV based on Co is 
0.01028 hr.sup.-1. The equivalent rates of feed (moles/hr) are as follows: 
C=14.83; O=4.82; Co=0.099; and Mn=0.0022 (remaining Mn is in the slag or 
leaves in the effluent). The amount of oxygen injected is about 163.8 
Kg/hr (5.12 KgMoles) and effluent from the reactor is led to a water 
scrubber. During operation at equilibrium, about 47.6 Kg of essentially 
pure Co (95.sup.+ %) are withdrawn every 8 hr. The molten metal may be 
cast as ingots for export from the plant, or the molten metal may be 
atomized as in Example 1 above to yield a powder. The composition of the 
metal particles is essentially the same as that of the melt beneath the 
slag. 
During the same 8 hour period, 1040L of scrubber water are collected 
containing 68.4 Kg of MnBr.sub.2 and 41.5 Kg of HBr. MnO accumulates in 
the slag at a rate of about 4.5 Kg/hr. Slag levels are adjusted by 
periodic withdrawals, and the slag withdrawn is atomized to 100 .mu.m 
(avg. part. diam.) as in Example 1 above, for recovery of its Mn content, 
if desired. 
EXAMPLE 4 
Ratio of Co/Mn=1/1 in residue fed; ratio of Co/Mn=1/1 in re-manufactured 
catalyst; Mn in the re-manufactured catalyst is recovered from the alloy 
melt and the MnBr.sub.2 from the scrubber (no MnO from the slag is 
converted). The effect of changing temperature and the amount of oxygen 
fed, is illustrated. 
A bath of Co/Mn/MnO/C (662/325/8.9/2.8) containing 1000 Kg of molten metal 
and slag is maintained at the given equilibrium composition at 
2000.degree. C. under 10 atm pressure in the reactor. Essentially all the 
MnO is rejected to slag which forms an immiscible layer above the molten 
metal. 292 Kg/hr of dry plant residue containing 2% Co, 2% Mn and 4% Br by 
wt, is injected into the molten alloy with oxygen. The WHSV based on Co is 
5.886.times.10.sup.-3 hr.sup.-1. The equivalent rates of feed (moles/hr) 
are as follows: C=14.83; O=4.82; Co=0.099; and Mn=0.054 (remaining Mn is 
in the slag or leaves in the effluent). The amount of oxygen injected is 
about 160.8 Kg/hr (5.03 KgMoles) and effluent from the reactor is led to a 
water scrubber. During operation at equilibrium, about 69.6 Kg of molten 
alloy are withdrawn every 8 hr, and atomized to form a powder metal as in 
Example 1 above. The composition of the metal powder is essentially the 
same as that of the melt beneath the slag. 
During the same 8 hour period, 1040L of scrubber water are collected 
containing 90.3 Kg of MnBr.sub.2 and 24.2 Kg of HBr. MnO accumulates in 
the slag at a rate of about 0.08 Kg/hr. Slag levels are adjusted by 
periodic withdrawals, and the slag withdrawn and atomized as in Example 1 
above. 
The 69.6 Kg of powder metal, the scrubber water and 127 Kg of glacial HOAc 
are combined as in Example 1, to produce a solution of mixed acetates and 
bromides of Co and Mn in which solution Co and Mn are 4.1% and 4.0% by wt, 
respectively. There is essentially no free acid. As in Example 1 above, if 
necessary, slag is digested with HOAc to yield a solution of Mn(OAc).sub.2 
and as much of this solution as necessary is added to provide the desired 
1/1 ratio of Co/Mn in the re-manufactured catalyst. Also as before, 
re-manufactured catalyst is filtered to remove suspended carbon in the 
alloy. 
EXAMPLE 5 
Ratio of Co/Mn=1/1 in residue fed; conditions for producing essentially 
pure cobalt (99..sup.+ % pure) by rejecting essentially all Mn from molten 
metal. 
A bath of Co/Mn/MnO/C (485/4.5/509.3/7) containing 1000 Kg of molten metal 
and slag is maintained at the given equilibrium composition at 
1700.degree. C. under 10 atm pressure in the reactor. Essentially all the 
MnO is rejected to slag which forms an immiscible layer above the molten 
metal. 292 Kg/hr of dry plant residue containing 2% Co, 2% Mn and 4% Br by 
wt, is injected into the molten alloy with oxygen. The WHSV based on Co is 
0.0119 hr.sup.-1. The equivalent rates of feed (moles/hr) are as follows: 
C=14.83; O=4.82; Co=0.099; and Mn=0.0001 (remaining Mn is in the slag or 
leaves in the effluent). The amount of oxygen injected is about 190.4 
Kg/hr (5.95 KgMoles) and effluent from the reactor is led to a water 
scrubber. During operation at equilibrium, about 47.1 Kg of essentially 
pure Co (99.sup.+ %) are withdrawn every 8 hr. The molten metal may be 
cast as ingots for export from the plant, or the molten metal may be 
atomized as in Example 1 above to yield a powder. The composition of the 
metal particles is essentially the same as that of the melt beneath the 
slag. 
During the same 8 hour period, 1040L of scrubber water are collected 
containing 65.9 Kg of MnBr.sub.2 and 66 Kg of HBr. These may be stored for 
the re-manufacture of catalyst in the future, or exported for any other 
use. MnO accumulates in the slag at a rate of about 6 Kg/hr. Slag levels 
are adjusted by periodic withdrawals, and the slag withdrawn is atomized 
to 100 .mu.m (avg. part. diam.) as in Example 1 above, for recovery of its 
Mn content, if desired. 
EXAMPLE 6 
Ratio of Co/Mn=1/3 in residue fed; melt recovered is used to re-manufacture 
catalyst with Co/Mn=3/1. 
A bath of Co/Mn/MnO/C (285/694/0/21) containing 1000 Kg of molten metal and 
slag is maintained at the given equilibrium composition at 2000.degree. C. 
under 10 atm pressure in the reactor. 292 Kg/hr of dry plant residue 
containing 2% Co, 6% Mn and 4% Br by wt, is injected into the molten alloy 
with oxygen. The WHSV based on Co is 5.83.times.10.sup.-3 hr.sup.-1. The 
equivalent rates of feed (moles/hr) are as follows: C=13.6; O=5.07; 
Co=0.099; and Mn=0.26 (remaining Mn is in the slag or leaves in the 
effluent). The amount of oxygen injected is about 131.1 Kg/hr (4.10 
KgMoles) and effluent from the reactor is led to a water scrubber. During 
operation at equilibrium, about 160 Kg of molten alloy are withdrawn every 
8 hr, and atomized to form a powder metal as in Example 1 above. The 
composition of the metal powder is essentially the same as that of the 
melt beneath the slag. 
During the same 8 hour period, 1040L of scrubber water are collected 
containing 98.3 Kg of MnBr.sub.2 and 18.6 Kg of HBr. No MnO accumulates in 
the slag. Slag levels are adjusted by periodic withdrawals. 
The 160 Kg of atomized metal, 1040L of scrubber water and 329 Kg of glacial 
HOAc are combined as in Example 1, to produce a solution of mixed acetates 
and bromides of Co and Mn in which solution Co and Mn are 3.6% and 10.6% 
by wt, respectively. There is essentially no free acid. Also as before, 
re-manufactured catalyst is filtered to remove suspended carbon in the 
alloy. 
EXAMPLE 7 
Ratio of Co/Mn=1/3 in residue fed; effect of a 1% increase in gaseous 
oxygen fed in Example 6; result--increases MnO formed in slag and reduces 
carbon in the alloy; re-manufacture of catalyst with Co/Mn=1/3. 
The bath maintained at the same equilibrium composition and under the same 
temperature and pressure conditions as in Example 6, is fed with the same 
amount of dry plant residue (292 Kg/hr) to provide a WHSV based on Co of 
5.96.times.10.sup.-3 hr.sup.-1. The equivalent rates of feed (moles/hr) 
are as follows: C=13.6; O=5.07; Co=0.099; and Mn=0.25 (remaining Mn is in 
the slag or leaves in the effluent). The amount of oxygen injected is 
about 132.8 Kg/hr (4.15 KgMoles) and effluent from the reactor is led to a 
water scrubber. During equilibrium operation, the bath composition is 
Co/Mn/MnO/C (288/683/22/6 by wt). About 157 Kg of molten alloy are 
withdrawn every 8 hr, and atomized to form a powder metal as in Example 1 
above. The composition of the metal powder is essentially the same as that 
of the melt beneath the slag. 
During the same 8 hour period, 1040L of scrubber water are collected 
containing 99 Kg of MnBr.sub.2 and 18.1 Kg of HBr. MnO accumulates in the 
slag at 0.45 Kg/hr. Slag levels are adjusted by periodic withdrawals. 
The 157 Kg of atomized metal, the 1040L of scrubber water and 323 Kg of 
glacial HOAc are combined as in Example 1, to produce a solution of mixed 
acetates and bromides of Co and Mn in which solution Co and Mn are 3.6% 
and 10.5% by wt, respectively. There is essentially no free acid. As in 
Example 1 above, if necessary, slag is digested with HOAc to yield a 
solution of Mn(OAc).sub.2 and as much of this solution as necessary is 
added to provide the desired 1/3 ratio of Co/Mn in the re-manufactured 
catalyst. Also as before, re-manufactured catalyst is filtered to remove 
suspended carbon in the alloy. 
EXAMPLE 8 
Residue fed is a mixture of plant residue and earthy residue from a 
particular sludge pond in which there was no liner in the bottom of the 
pond. 
A bath of Co/Mn/MnO/C (409/244/337/8.8) containing 1000 Kg of molten metal 
and slag is maintained at the given equilibrium composition at 
1900.degree. C. under 10 atm pressure in the reactor. Essentially all the 
MnO is present in the slag which forms an immiscible layer above the Co/Mn 
alloy. A mixture of 292 Kg/hr of dry plant residue containing 2% Co, 2% Mn 
and 4% Br by wt, and 38.9 Kg/hr of dry earthy residue containing 15% Co, 
30% Mn, 26.2% O, 8.3% Al, 8.7% Si, and 10.3% C, by wt, is injected into 
the molten alloy with oxygen. The WHSV based on Co is 0.017 hr.sup.-1. The 
equivalent rates of feed (moles/hr) are as follows: C=15.16; O=5.46; 
Co=0.2; and Mn=0.13 (remaining Mn is in the slag, or, leaves the reactor 
in the effluent). The amount of oxygen injected is about 154.7 Kg/hr (4.83 
KgMoles) and effluent from the reactor is led to a water scrubber. During 
operation at equilibrium, about 149 Kg of molten alloy are withdrawn every 
8 hr, and atomized to form a powder metal as in Example 1 above. The 
composition of the particles is essentially the same as that of the melt 
beneath the slag. 
During the same 8 hour period, 1040L of scrubber water are collected 
containing 95 Kg of MnBr.sub.2 and 21.3 Kg of HBr. MnO accumulates in the 
slag at a rate of about 9.63 Kg/hr. Slag levels are adjusted by periodic 
withdrawals at 8 hr intervals, and the slag withdrawn is atomized to 100 
.mu.m (avg. part. diam.) with a stream of water under high pressure. 
The 149 Kg of atomized metal, the 1040 scrubber water and 323 Kg of glacial 
HOAc are combined in a vented heated vessel, and the temperature raised to 
90.degree. C., resulting in a solution of mixed acetates and bromides of 
Co and Mn in which solution Co and Mn are 7.3% and 6.3% by wt, 
respectively. There is essentially no free acid. As in Example 1 above, if 
necessary, slag is digested with HOAc to yield a solution of Mn(OAc).sub.2 
and as much of this solution as necessary is added to provide a desired 
ratio of Co/Mn in the re-manufactured catalyst. Also as before, 
re-manufactured catalyst is filtered to remove suspended carbon in the 
alloy.