Improvements in the Manufacture of Manganese Peroxide.
Year: 1893

page_text: Date of Application, 9th May, 1893
Complete Specification Left, 9th Feb., 1894-Accepted, 10th Mar., 1894
PROVISIONAL SPECIFICATION.
Improvements in the Manufacture of Manganese Peroxide.
GEORGE STACEY ALBRIGHT of Oldbury in the County of Worcester
Manufacturing Chemist and JOHN JAMES HOOD of 21 Shepherds Bush Road in
the County of Middlesex Chemist do hereby declare the nature of this invention to
be as follows:-
These improvements relate to the manufacture of that form of hydrated
peroxide of manganese known as Weldon mud, and for its suitable preparation
for the absorption of sulphuretted hydrogen in the purification of coal gas and
other chemical operations wherein sulphuretted hydrogen is to be absorbed.
In dealing with native ores of manganese, containing peroxide, we mix the
finely-ground ore with any suitable reducing agent, by preference coal dust or
other carbonaceous substance, and a sufficiency of sulphuric acid to combine with
the manganese, heating the mixture on a bed of a furnace or other suitable heating
arrangement when the reduction of the peroxide takes place with the formation of
sulphate of manganese. The material then lixiviated, and the solution of
sulphate of manganese employed for the preparation of the hydrated peroxide.
In dealing with the spent manganese peroxide from gas works containing
sulphide and other compounds of manganese, as well as free sulphur, we roast the
material for the preparation of sulphuric acid, during which operation much
manganese is converted into sulphate which substance we wash out by lixiviation,
employing the solution as hereafter described.
Or instead of roasting the sulphide of manganese, we treat it with sulphuric
acid, with or without the addition of hydrochloric acid, to form sulphate or a
mixture of sulphate and chloride of manganese, whilst the insoluble residue
consisting of sulphate of lime and free sulphur we press, dry, and distil for the
recovery of sulphur.
we
The solution of sulphate of manganese, obtained by any of the above processes
now employ as follows for the preparation of the hydrated peroxide of
manganese.
The solution is prepared as nearly neutral as possible, and an excess of calcium
chloride is mixed with it, more than sufficient to bring about the reaction,
MnSO4 + CaCl, = MnCl2 + CaSO.
By employing neutral solutions with excess of calcium chloride, and allowing
the solution to stand for some time the sulphate of lime settles out.
If a sufficient excess of calcium chloride has not been added requisite for the
subsequent operation of oxidation, more is added to the manganese chloride and
the solution is then run into an ordinary Weldon mud oxidiser with milk and lime
air blowing through the mixture in the customary manner as is done in chlorine
factories for the preparation and oxidation of the manganese hydrate. The
peroxide of manganese now known as Weldon mud is allowed to settle, washed,
pressed and dried, and is ready for such purposes as gas purification &c.
Calcium chloride obtained is employed again for the preparation of manganese
chloride from the sulphate.
Or instead of treating the manganese sulphate solutions as above described, we
precipitate the manganese with ammonia, previously freed from carbonic acid and
sulphuretted hydrogen gases, either in the form of gas or solution. The solution
is rendered slightly alkaline, with excess of ammonia and air is blown in to oxidise
the manganese, and cause the precipitation of the portion of manganese which is

page_text: held in solution by the sulphate of ammonia. "The sulphate of ammonia formed
during the reaction is drawn off and evaporated to a solid mass, and the hydrated
peroxide of manganese pressed, washed, and dried as before described.
Dated this 9th day of May 1893.
ERNEST SALAMAN,
61 & 62, Chancery Lane, London, Agent for Applicants.
COMPLETE SPECIFICATION.
Improvements in the Manufacture of Manganese Peroxide.
GEORGE STACEY ALBRIGHT of Oldbury in the County of Worcester
Manufacturing Chemist and JOHN JAMES HOOD of 21 Shepherds Bush Road
in the County of Middlesex Chemist, do hereby declare the nature of this invention
and in what manner the same is to be performed, to be particularly described and
ascertained in and by the following statement :-
These improvements relate to the manufacture of hydrated peroxide of
manganese and especially to that form known as Weldon mud, and for the suitable
preparation of such peroxide of manganese materials for the absorption of
sulphuretted hydrogen in the purification of coal gas and other chemical operations
wherein sulphuretted hydrogen is to be absorbed.
In dealing with the native ores of manganese containing peroxide we mix the
finely ground ore with any suitable reducing agent, by preference coal dust or
other carbonaceous substance, and a sufficiency of sulphuric acid to combine with
the manganese, heating the mixture on a bed of a furnace or other suitable heating
arrangement when the reduction of the peroxide takes place with the formation of
sulphate of manganese. The material is lixiviated, and the solution of sulphate of
manganese employed for the preparation of the hydrated peroxide. Manganese
ores which do not contain peroxide such as carbonate or compounds of the
monoxide MnO, are simply treated with sulphuric acid without the addition of
carbonaceous matters and heated on the bed of the furnace so as to decompose and
render insoluble any iron that may be in the ore.
In dealing with the fouled manganese residue, from gas works, containing
sulphide and other compounds of manganese, as well as free sulphur we roast the
material for the preparation of sulphuric acid during which operation much
manganese is converted into sulphate which substance we wash out by lixiviation
employing the solution as hereafter described, and the residue insoluble in water if
it contains an appreciable amount of insoluble oxides of manganese is treated with
sulphuric acid and again lixiviated or the whole of the manganese present may be
rendered soluble by treatment with the necessary quantity of sulphuric acid and
water without previous lixiviation.
Or instead of roasting the fouled manganese material (for instance a fouled
residue from the gas works) we heat with sulphuric acid, with or without the
addition of hydrochloric acid, to form sulphate or a mixture of sulphate and
chloride of manganese, whilst the insoluble residue consisting of sulphate of lime
and free sulphur we press, dry and distil for the recovery of sulphur. The
solution of sulphate of manganese obtained by any of the above processes we now
employ as follows for the preparation of the hydrated peroxide of manganese.
The solution is prepared as nearly neutral as possible and an excess of calcium
chloride is mixed with it, more than sufficient to bring about the reaction
MnSO₁ + CaC₁₂ = MnCl + CaSO̟.
By employing neutral solutions with excess of calcium chloride, and allowing

page_text: free from the manganese chloride, employing a strong solution of calcium chloride
for the washing so as not to dilute the manganese chloride solution by employing
water.
If a sufficient excess of calcium chloride has not been added requisite for the
subsequent operation of oxidation, more is added to the manganese chloride which
may be done as above described by washing the sulphate of lime precipitated with
calcium chloride and the solution is then run into an ordinary Weldon mud
oxidiser with milk of lime, air being blown through the mixture in the customary
manner as is done in chlorine factories for the preparation and oxidation of the
manganese hydrate. As it is essential for the successful performance of this
oxidation process that there should be a large amount of calcium chloride in the
manganese solution, when we find that by washing our residues as above described
with calcium chloride, that there is not sufficient of this body present with the
manganese chloride, we first slake the lime in the usual manner with water and
then add the requisite amount of calcium chloride to the lime in forming milk of
lime, and employ this hydrate of lime plus calcium chloride in the precipitation of
the manganese.
The hydrated peroxide of manganese material is allowed to settle, washed
pressed and dried, and is then ready for use. The calcium chloride obtained is
employed again for the preparation of manganese chloride from the sulphate, so
that by this method of working only sulphuric acid is employed and the calcium
chloride resulting from the operations is used over and over again with the
addition in each cycle of operations of the small amount necessary to make up for
unavoidable losses.
Or instead of treating the manganese sulphate solutions as above described, we
precipitate the manganese with ammonia, previously freed from carbonic acid and
sulphuretted hydrogen gases, either in the form of gas or solution. The solution
is rendered slightly alkaline with excess of ammonia, and air is blown in to oxidise
the manganese, and cause the precipitation of the portion of the manganese which
is held in solution by the sulphate of ammonia. The excess of ammonia which is
blown out during the oxidation process is passed into the ordinary scrubber or
absorber containing water or acid. The sulphate of ammonia formed during the
reaction is drawn off and evaporated, and the hydrated peroxide of manganese
pressed, washed and dried as before described.
By this alternative method of preparation the manganese material is obtained
containing only the oxides MDO, and MnO and no lime CaO and which material
after it has been fouled at the gas works and roasted or treated with acid for the
recovery of the sulphur, will give no insoluble residue of calcium sulphate, but in
this case the further process of regeneration is substantially as above described.
The insoluble residue of calcium sulphate mentioned in the last paragraph may
also be avoided by treating Weldon mud with a sufficient quantity of dilute cold
hydrochloric acid, or other suitable acid, to dissolve the bases present, whereby
the greater part of the bases riz. lime and monoxide of manganese are rendered
soluble and may be removed by pressing and washing from the insoluble hydrated
peroxide. The partially debased or pure form of hydrated peroxide thus
produced after fouling with sulphuretted hydrogen in the gas works may be
subsequently treated with sulphuric acid and regenerated substantially in any of
the manners described.
Having now particularly described and ascertained the nature of our said inven-
tion and in what manner the same is to be performed we declare that what we
claim is
1. The preparation of the hydrated peroxide of manganese or of the mixture of
the peroxide with the monoxide and calcium oxide known as Weldon mud for use
in gas purification from native manganese ores ¡by employing sulphuric acid and
calcium chloride instead of hydrochloric acid so as to avoid the formation of
chlorine gases substantially as above described.

page_text: 2. The regeneration of the spent manganese materials from gas works into the
hydrated form of peroxide of manganese known as Weldon mud by means of
sulphuric acid and calcium chloride substantially as above described.
3. The preparation of brimstone from the spent manganese residues of gas works
by dissolving out the manganese with sulphuric acid and distilling the insoluble
residues substantially as above described.
4. The employment of calcium chloride in washing the insoluble residues and
for making the milk of lime requisite for the preparation of Weldon mud so as to
render it unnecessary to concentrate the solution by boiling substantially as
described.
5. The preparation of the hydrated peroxide of manganese or mixtures of this
oxide with the monoxide by precipitation of sulphate of manganese by means of
ammonia and the recovery of the sulphate of ammonia substantially as described.
6. In the preparation of hydrated peroxide of manganese the removal or partial
removal of the bases lime and manganese monoxide in the manner substantially
described.
7. The preparation of debased hydrated manganese material substantially as
described for use in the removal of sulphuretted hydrogen from coal gas.
Dated this 9th day of February 1894.
ERNEST SALAMAN,
Pinner's Hall, Great Winchester Street, Agent for Applicants.