Oil well drilling clay conditioner

A high quality chrome lignosulfonate for use as an oil well drilling additive is produced from molecular weight and/or high carbohydrate containing spent sulfite liquor. The additive is obtained by adding boron prior to the oxidation of the lignosulfonate and complexing with chrome. The use of boron allows the raw material spent sulfite liquor source to be less pure and from a wide variety of wood.

BACKGROUND OF THE INVENTION 
The present invention relates to additives or conditioners for oil well 
drilling fluids, and more particularly to a boron-chrome lignosulfonate 
drilling fluid additive or conditioner. 
The most commonly used drilling fluids are aqueous dispersions of clay. The 
drilling fluid or "mud" is pumped down a hollow drill string, through the 
bit at the bottom, and up the annulus formed by the hole or casing and the 
drill string to the surface. After reaching the surface, various 
operations are performed on the drilling fluid to remove the cuttings and 
formation material thereform. The drilling fluid is then treated with 
additives to obtain a desired set of rheological properties, and is then 
pumped back into the well in a continuous circulating process. 
A satisfactory drilling fluid must have various desired functions, such as 
gelling during temporary work stoppage and other functions well known in 
the art, which contribute to the success of the well drilling operation. 
In order to accomplish these various functions, it has been found 
necessary to incorporate certain additives in the drilling fluid. Modified 
lignosulfonates derived from spent sulfite liquor obtained from the 
pulping of woods have proven to be effective additives for obtaining the 
desired properties in drilling fluids. 
In order to improve the effectiveness of the liqnosulfonates as drilling 
fluid additives, King et al. U.S. Pat. No. 2,953,473 recommended the use 
of certain metal salts of liqnosulfonate wherein the metals are chromium, 
aluminum, iron, copper or combinations thereof, which salts may or may not 
be oxidized. Of the metal lignosulfonate salts disclosed in the King et 
al. patent, the chromium salt has been found to be very effective so that 
the chromium salt by itself or in combination with other metals has become 
commonly used as a drilling fluid additive. See for example, Hoyt, U.S. 
Pat. No. 3,035,042 in which the additive is an iron-chromium 
lignosulfonate complex, and Van Dyke et al. U.S. Pat. No. 3,076,758 
wherein the additive is an iron-free chromium lignosulfonate. Chrome-free 
additives are also well known, and Kelley U.S. Pat. No. 4,374,738 is an 
example of such a drilling fluid composition. Additionally, boron has been 
complexed with chrome free lignosulfonates for drilling fluid additives as 
discussed in application Ser. No. 06/372,141 filed Apr. 27, 1982, now U.S. 
Pat. No. 4,457,853, and assigned to the assignee of the present 
application. Boron has also been added to lignosulfonates to increase set 
times for oil well cementing compositions as described in Childs et al., 
U.S. Pat. No. 4,149,900. 
One problem with utilizing lignin containing products such as the spent 
sulfite liquor from pulping processes to produce a chrome complexed 
drilling fluid additive is that such liquor does not contain pure 
lignosulfonate. The spent sulfite liquor generally contains only about 40% 
to 60% by weight lignosulfonates with the remainder being carbohydrates 
and other organic and inorganic constituents dissolved in the liquor. If 
these carbohydrates remain in the liquor, they react with chrome during 
the oxidation-reduction-complexing reaction to form a gel resulting in a 
poor quality oil drilling mud conditioner. As a result, the spent sulfite 
liquor must be subjected to different treatments such as alkaline, acid, 
or heat treatments as well as reacted with other chemicals to modify or 
remove various undesired non-lignin constituents. However, such additional 
processing of the spent sulfite liquor is costly. It is thus desirable to 
provide a high quality chrome lignosulfonate for use as an oil well 
drilling mud conditioner which is produced from less pure spent sulfite 
liquors containing sugar acids and polysaccharide carbohydrates. 
SUMMARY OF THE INVENTION 
A high quality chrome lignosulfonate for use as an oil well drilling 
additive made from high carbohydrate containing spent sulfite liquor. The 
carbohydrates are complexed with boron prior to oxidation of the 
lignosulfonates and complexing with chrome resulting in an oxidized 
complexed chrome lignosulfonate. When used as an additive in an oil well 
drilling fluid, the oxidized complexed chrome lignosulfonate produced from 
boron treated raw material liquor exhibits improved rheological properties 
over other drilling fluid additives. 
The boron complexed chrome lignosulfonate eliminates the necessity of 
purifying spent sulfite liquor and therefore significantly decreases the 
production cost of the additive. 
DETAILED DESCRIPTION OF THE INVENTION 
A boron compound, preferably boric acid, is complexed with a sulfonated 
lignin containing material prior to the oxidation of the lignin containing 
material with chrome. The resulting boron-chrome lignosulfonates provide a 
drilling fluid additive which significantly enhances the rheological 
properties of a drilling fluid. Additionally, the boron-chrome 
lignosulfonates can be obtained from a spent sulfite liquor that is less 
pure having high carbohydrate constituents. The liquor may be available 
from a wide variety of wood, including hardwood. More specifically, the 
boron-chrome lignosulfonates of the present invention exhibit improved 
apparent viscosities, yield points, water loss, and ten minute gel 
strengths, as well as higher temperature stability, compared to chrome 
lignosulfonates without boron. 
The lignin containing starting materials which are useful in making the 
products described herein are well known and, in general, they are 
described in the aforementioned King et al. patent. The desired starting 
lignosulfonates are usually spent lignin liquors obtained from the pulping 
of wood. Lignosulfonates of hard wood or soft wood origin, obtained from 
calcium sulfite spent liquor provide a particularly desirable source of 
starting raw material in the practice of this invention. Preferably, these 
lignosulfonates are treated to remove their reducing sugars by 
fermentation (alcohol or yeast) or by using calcium bisulphite under high 
temperature and high pressure. The spent sulfite liquor and particularly 
the sugar destroyed, calcium based spent sulfite liquors, will hereinafter 
be referred to generally as "sulfonated lignin containing materials". 
The sulfonated lignin containing materials obtained from the pulping of 
wood will generally contain lignins as well as other constituents. For 
example, the spent sulfite liquor generally contains only about 40% to 60% 
by weight of lignosulfontes the remainder being carbohydrates such as 
reducing sugars, sugar acids and polysaccharides and other organic and 
inorganic constituents dissolved in the liquor. Reducing sugars are those 
carbohydrates having up to six or seven carbon atoms such as glucose, 
arabinose and other pentoses and hexoses. These carbohydrates can easily 
react with chrome during the oxidation-reduction-complexing reaction to 
form a gel resulting in a poor quality oil well drilling mud conditioner. 
In order to obtain a more pure starting material the sulfonated lignin 
containing materials are thus generally subjected to different treatments 
such as alkaline, acid or heat treatments as well as being reacted with 
various chemicals to modify or remove some of the non-lignin constituents. 
In particular, the reducing sugars are removed by fermentation or other 
known methods. 
Surprisingly, however, it has been found that the addition of boron prior 
to the reaction with chrome during the oxidation-reduction-complexing 
reaction of the lignosulfonate material enables the lignosulfonate to 
react with chrome and form the proper chrome complex for drilling mud 
conditioning even though the raw material contains carbohydrates. The 
theory is offered, but not bound by, that the boron is complexing with the 
cis-diol groups of the carbohydrates in the spent sulfite liquor in the 
following manner: 
##STR1## 
The boron in accordance with the above example eliminates the possible 
reaction of the carbohydrate portion of the lignosulfonates with chrome 
during the oxidation-reduction-complexing reaction to thereby prevent gel 
formation. The carbohydrate being complexed by boron is believed to be the 
larger molecular weight hemicellulose or polysaccharide that under chrome 
reaction can easily form a gel with the lignosulfonate resulting in a poor 
quality oil well drilling additive. Thus, when using boron in accordance 
with the present invention, it is not necesary to separate the lignin 
containing constituents from the other constituents in the spent sulfite 
liquor. The use of boron allows the raw material source to be less pure 
and from a wide variety of wood, including 100% hardwood. 
The products of the present invention are obtained by adding a boron 
compound to a sulfonated lignin containing material under acidic 
conditions prior to the oxidation of the lignosulfonate with chrome, and 
finally followed by recovering the boron-chrome lignosulfonate. 
Additionally, external oxidation of the sulfonated lignin-containing 
material may also be accomplished with manganese dioxide (MnO.sub.2) or 
any of the oxidizing agents disclosed in the aforementioned King et al 
patent followed by complexing with a chrome compound and recovery of the 
boron-chrome lignosulfonate. King et al discloses that such oxidizing 
agents may be selected from the group consisting of hydrogen peroxide, 
ozone, lead dioxide, chromic acid, chlorine, alkali and alkaline earth 
metal hypochlorites, alkali metal chromate, alkali metal permanganate, 
alkali metal persulfate, alkali metal perborate, and combinations thereof. 
Thus, reduced trivalent chrome compounds may be employed as a complexing 
agent if the sulfonated lignin-containing material has previously been 
oxidized. 
Initially, the sulfonated lignin containing material may optionally be 
activated by heat treatment with an acid, aldehyde polymerization, 
oxidation with an oxidizing agent, ultrasonic energy, or a combination 
thereof. Where such activation step is used, mineral acids such as 
sulfuric acid, nitric acid, phosphoric acid or hydrochloric acid may be 
effectively employed, with sulfuric acid constituting the preferred 
mineral acid. Acid activation may be conveniently carried out at a 
temperature of from about 60.degree. C. to about 90.degree. C. for a 
period of about one hour using from about 10 to about 35 weight percent, 
preferably from about 20 to about 25 percent of acid based on the solids 
content of the lignosulfonates starting material, and depending on the 
particular lignosulfonate starting material. 
The sulfonated lignin containing material, which may have been activated, 
is then reacted with a boron compound, which is, preferably, boric acid 
(H.sub.3 BO.sub.3), followed by oxidation, preferably, with chrome. The 
addition of boron and the oxidation with chrome are both carried out under 
acidic conditions, using any one of the aforementioned mineral acids, 
preferably sulfuric acid. 
Although boric acid is the boron compound of choice in the practice of this 
invention, other compounds of boron may also be used, if desired. Such 
boron compounds include sodium tetraborate pentahydrate, sodium metaborate 
and hydrates, and sodium tetraborate anhydrous and decahydrate (borax). 
Also, the boron halides such as fluorides, chlorides, bromides and iodides 
as well as boron oxide and boron sulfide may be used. 
The amount of boron compound which can be used depends on the type of 
lignosulfonate starting material. Sufficient boron compound is added so 
that the boron content, in the final product is from about 1 to about 3 
weight percent, and is preferably about 2 percent. 
Chromium compounds useful in the practice of this invention may include 
hexavalent oxidizing chrome compounds such as sodium dichromate, potassium 
dichromate and chromic acid (chromium trioxide). With external oxidation 
processing, reduced trivalent chrome compounds can be used alone or in 
combination with hexavalent chrome compounds. Reduced chrome compounds 
could be chrome sulfate and hydrates, chrome nitrate, chrome halides and 
chrome acetate. 
The amount of chromium compound which can be used also depends on the type 
of lignosulfonate starting material. Sufficient chromium compound is added 
so that the chrome content, based on the final product, is from about 2 to 
about 5 weight percent, and is preferably from about 3 to about 4 weight 
percent. 
The addition of the boron to the lignosulfonate is carried out under highly 
acidic conditions at atmospheric pressure at a temperature of from about 
60.degree. C. to about 100.degree. C. The reacton mass is then held at a 
temperature of from about 80.degree. C. to about 100.degree. C. from about 
30 minutes to about one hour. Following this, the reaction mass is cooled 
to between about 55.degree. C. and 60.degree. C. 
The oxidation of the lignosulfonate with the chromium compound is carried 
out under highly acidic conditions at atmospheric pressure and a 
temperature of from about 50.degree. C. to about 70.degree. C. Since this 
oxidation reaction is highly exothermic, the mixture must be cooled with 
agitation so that the temperature does not exceed about 70.degree. C. The 
rate of addition of the chrome depends on its purity and concentration, 
the concentration of the solids in the lignosulfonate and the 
effectiveness of agitation. This rate is usually controlled so that the 
reaction is completed within several minutes to two hours, preferabaly 
within ten minutes to one hour. 
After completion of the oxidation reaction, it is desirable to adjust the 
pH of the resulting mixture by the addition of a suitable base such as an 
alkali metal hydroxide or alkaline earth metal hydroxide to raise the pH 
to about 3.0 to 4.0. These hydroxides include sodium hydroxide, potassium 
hydroxide, calcium hydroxide and lithium hydroxide. The neutralization 
step is usually carried at between 50.degree. C. and 60.degree. C., which 
is the temperature of the mixture upon completion of the oxidation step, 
but may also be carried out at ambient conditions. Due to its low cost, 
sodium hydroxide constitutes the hydroxide of choice and is usually used 
in dilute concentrations, as for example, in a 20% solution. 
The recovered boron-chrome lignosulfonates contain from about 1% to about 
3%, preferably about 2%, boron, and from about 2% to about 5%, preferably 
from about 3% to about 4%, chrome, based on the weight of the boron-chrome 
lignosulfonate product. 
When using sulfuric acid in the activation step, or in the direct oxidation 
of the sulfonated lignin containing materials, calcium sulfate (gypsum) 
will precipitate from the mixture. Thus, after the neutralization step, 
the calcium sulfate precipitate must be removed by any well known method, 
such as rotary vacuum fulters, centrifugation, filtration, settling, and 
the like. 
The resulting filtrate solution, after removal of the precipitated gypsum, 
may be spray dried at 230.degree. F. to 240.degree. F. inlet temperature 
to recover solid powder boron-chrome lignosulfonate. Additionally, the 
resulting filtrate solution may be shipped in liquid form. Whether the 
ultimate product is a liquid or a spray dried powder, the boron-chrome 
lignosulfonates produced by the present invention exhibit all the 
desirable rheological attributes required for a good drilling fluid clay 
conditioner. These properties include apparent viscosity, yield point, 
water loss, and ten minute gel strength.

The following examples will further serve to illustrate the preparation of 
the products of this invention and their advantageous drilling fluid 
conditioning properties. It must be understood, however, that these 
examples are merely illustrative and are not intended to limit the scope 
of the present invention. 
In the following examples, all measures of apparent viscosity, yield point, 
gel strength and Fann degree readings were made in accordance with API 
recommended practice 13B "Standard Procedure For Testing Drilling Fluids", 
Sixth Edition, April, 1976, published by the American Petroleum Institute. 
EXAMPLE I 
This example illustrates the applicability of the invention to spent 
sulfite liquor obtained from softwood with only the reducing sugars 
destroyed. Example I-A exemplifies a drilling fluid additive with no boron 
added while example I-B exemplifies a drilling fluid additive with boron 
added. 
EXAMPLE I-A 
50 grams of a sugar destroyed, calcium base softwood spent sulfite liquor 
(B-41 Lignosol B, available from Reed Lignin Inc.) solids as 25% solution 
in water was heated to 45.degree. C. and treated with 10 grams of sulfuric 
acid (100% ) as a 40% solution in water (25 grams) under mechanical 
agitation. The acidic reaction mixture was heated to 52.degree. C. and 
treated with 5.1 grams of sodium dichromate dihydrate (100%) as a 20% 
solution in water (25.5 grams). The mixture was cooled to 25.degree. C. 
and neutralized from 1.9 pH to 4.0 pH by adding 20 milliliters of 120 
grams per liter calcium oxide slurry (2.4 grams of CaO). The reaction mass 
was heated to 40.degree. C. and filtered to remove precipitated gypsum 
(calcium sulfate dihydrate, 13 grams) which was discarded. The filtrate 
solution, containing approximately 50.9 grams of solids as a 19.2% 
solution (265 grams), was spray dried at 230.degree. F. inlet temperature 
to recover solid powder chrome lignosulfonate. 
EXAMPLE I-B 
Another 50 grams of sugar destroyed calcium base softwood spent sulfite 
liquor, as in Example I-A, was diluted to 25% solids and treated with 10 
grams of sulfuric acid as in Example I-A. The reaction mass was heated to 
70.degree. C. and 7.2 grams of boric acid added. The reaction mass was 
cooled to 57.degree. C. over a 25 minute period and 5.5 grams of sodium 
dichromate dihydrate (100%) as a 20% solution in water (27.5 grams) added 
over a 10 minute period. The resulting reaction mixture was neutralized 
from 2.0 pH to 3.5 pH with 14 milliliters of 120 grams per liter calcium 
oxide slurry (1.68 grams of CaO). The reaction mass was filtered to remove 
precipitated gypsum (calcium sulfate dihydrate, 13 grams) which was 
discarded. The resulting filtrate solution, containing approximately 53.5 
grams of boron-chrome lignosulfonate, was spray dried at 230.degree. F. 
inlet temperature to recover solid powder boron-chrome lignosulfonate. 
The two materials recovered in Examples I-A and I-B were evaluated as an 
additive in calcium montmorillonite clay system and compared to 
commercially available chrome lignosulfonates as well as chrome-free 
lignosulfonate for oil well drilling clay conditioning. The comparative 
results are shown in Table 1. 
The evaluation test is described below using aged 28% Panther Creek calcium 
bentonite prepared in de-ionized water. 
Test Procedure 
(1) Add 1.75 grams of salt to a barrel equivalent (350 cc) of 28% by weight 
Panther Creek bentonite which has been aged for at least seven days. 
(2) Stir for three minutes on a Hamilton Beach mixer at 7500.+-.500 rpm. 
(3) Add 5 grams of the sample to be tested. 
(4) After the sample has been mixed with the mud for one minute, add 
sufficient caustic soda solution (1 ml=0.25 gram sodium hydroxide) so that 
the pH measures 9.5.+-.0.1 after 20 minutes of total stirring time. 
(5) The mud is stirred on a Hamilton Beach Model 30 mixer at 7500.+-.500 
rpm during this 20 minute stirring time. 
(6) Measure the flow properties on a Fann Model 35G viscosimeter. Record 
the values of apparent viscosity (cps), yield point (lbs./100 sq.ft.), 
degree Fann readings (600, 300, 3) and 10 minute gel strength (lbs./100 
sq.ft.). 
(7) Hot roll the sample overnight at 150.degree. F. 
(8) Cool the samples to room temperature. Readjust the pH to 9.5.+-.0.1 
with additional caustic soda solution and stir for five minutes before 
measuring hot roll properties. 
(9) Measure the hot rolled flow properties as described in (6). 
(10) Charge the hot rolled mud system to a high pressure stainless steel 
system, pressurize to 500 lbs./sq.in. with nitrogen gas pressure and roll 
at 300.degree. F. for three hours. 
(11) Cool the samples to room temperature. Readjust the pH to 9.5.+-.0.1 
with additional caustic soda and stir for five minutes before measuring 
Bombed properties. 
(12) Measure the Bombed rheological flow properties as described in Step 
(6) above. 
EXAMPLE II 
This example illustrates the applicability of the invention to spent 
sulfite liquor obtained from hardwood with only the reducing sugars 
destroyed. Example II-A exemplifies a drilling fluid additive with no 
boron added while example II-B exemplifies an additive with boron added. 
Example II-A 
50 grams of sugar destroyed calcium hardwood spent sulfite liquor (B-41 
Norlig 41 available from Reed Lignin Inc.) solids as a 25% solution in 
water was heated to 50.degree. C. and treated with 9 grams of sulfuric 
acid (100%) as a 40.6% solution in water (22.2 grams) under mechanical 
agitation. The acidic reaction mixture was heated to 85.degree. C. and 
held 45 minutes. It was then cooled with air over a 15 minute period to 
57.degree. C. and 6.5 grams sodium dichromate dihydrate (100%) as a 20% 
solution in water (32.5 grams) added slowly with water cooling of the 
exothermic reaction. The reaction mixture was neutralized at 52.degree. C. 
from 1.3 pH to 3.4 pH with 25 milliliters of 120 gram per liter calcium 
oxide slurry (3 grams of CaO) and subsequently filtered to remove 
precipitated gypsum (calcium sulfate dihydrate, 10 grams) which was 
discarded. The filtrate, containing 54.3 grams of chrome lignosulfonate, 
was spray dried at 230.degree.-240.degree. F. inlet temperature to recover 
solid powder chrome lignosulfonate. 
Example II-B 
Another 50 grams of sugar destroyed calcium base hardwood spent sulfite 
liquor was diluted to 25%, as in Example II-A. The solution was heated to 
85.degree. C. and treated with 9 grams of sulfuric acid as in Example II-A 
and 7.2 grams of boric acid. The reaction mixture was held at 80.degree. 
C. for 30 minutes, cooled to 55.degree. C. with air and 6.5 grams of 
sodium dichromate dihydrate (100%) as a 20% solution (32.5 grams) added 
slowly with water cooling. The reaction mixture, cooled to 55.degree. C., 
was neutralized from 1.9 pH to 3.5 pH with 35 milliliters of 120 gram per 
liter calcium oxide slurry (4.2 grams of CaO) and fitered to remove 
precipitated gypsum (calcium sulfate dihydrate, 12 grams) which was 
discarded. The filtrate, containing 58.9 grams of boron-chrome 
lignosulfonate, was spray dried at 240.degree. F. inlet temperature to 
recover solid powder boron-chrome lignosulfonate. 
The two materials of Example II-A and II-B were evaluated as in Example 1. 
Test results are shown in Table 1. 
EXAMPLE III 
This example illustrates the applicability of the invention spent sulfite 
liquor obtained from hardwood without removing the reducing sugars. 
Example III-A exemplifies a drilling fluid additive with no boron added 
while example III-B exemplifies an additive with boron added. 
300 grams of low reducing sugar calcium base hardwood spent sulfite liquor 
(Norlig 41d available from Reed Lignin Inc.) solids as a 35% solution in 
water was heated to 40.degree. C. and treated with 54 grams of sulfuric 
acid (100%) as a 50% solution in water (108 grams) under mechanical 
agitation. The acidic reaction mixture was heated to 70.degree. C. and 24 
grams of manganese dioxide (100%) as a 35% slurry in water was added. The 
exothermic reaction reached a final temperature of 77.degree. C. and was 
held for 25 minutes. The reaction mass at pH 2.6 was filtered to remove 
precipitated gypsum (calcium) sulfate dihydrate, 93 grams) which was 
discarded. The resulting filtrate solution contained 281.7 grams of solids 
as a 31.2% solution in water (903 grams) and was the raw material for 
Examples III-A and III-B. 
Example III-A 
130 grams of filtrate solids (416.7 grams of solution at 31.2%) was heated 
to 45.degree. C. and treated with 16 grams of sulfuric acid (100%) as a 
50% solution in water (32 grams). The reaction batch was heated further to 
52.degree. C. and 16 grams of sodium dichromate dihydrate (100%) added as 
a 35% solution in water (45.7 grams). The exothermic reaction mass at 
58.degree. C. was neutralized from pH 2.3 to pH 3.3 with 34 grams of 5 
normal sodium hydroxide (5.7 grams of 100% NaOH). The resulting reaction 
mass, containing approximately 157.8 grams of manganese-chrome 
lignosulfonate, was spray dried at 240.degree. F. inlet temperature to 
recover solid powder manganese-chrome lignosulfonate. 
Example III-B 
A second 130 grams of filtrate solids (416.7 grams of solution at 31.2%) 
from III above was heated to 45.degree. C. and treated with 16 grams total 
of sulfuric acid (100%) as a 50% solution in water (32 grams). The batch 
was heated further to 70.degree. C. and treated with 14.9 grams of boric 
acid. It was held at 80.degree.-90.degree. C. for 45 minutes, cooled to 
55.degree. C. and reacted with 16 grams of sodium dichromate dihydrate 
(100%) as a 35% solution in water (45.7 grams). The exothermic reaction 
mass at 58.degree. C. was neutralized from pH 2.3 to pH 3.3 with 30 grams 
of 5 normal sodium hydroxide (5 grams of 100% NaOH). The resulting 
reaction mass, containing approximately 161.1 grams of 
boron-manganese-chrome lignosulfonate as a 30% water solution (537 grams) 
was spray dried at 240.degree. F. inlet temperature to recover solid 
powder boron-manganese-chrome lignosulfonate. 
The two products of Example III-A and III-B were evaluated as in Example I. 
Test results are shown on Table 1. 
TABLE 1 
__________________________________________________________________________ 
Chrome Chrome Chrome-Free 
Lignosulfonate 
Lignosulfonate 
Lignosulfonate 
EXAMPLE I 
EXAMPLE II 
EXAMPLE III 
Reference 1 
Reference 2 
Reference 3 
A B A B A B 
__________________________________________________________________________ 
INITIAL 
Apparent Viscosity, cps 
36 24 22 31 19 24 19 44 28 
Yield Point 37 17 13 33 9 19 8 46 17 
(Lbs./100 sq.ft.) 
Fann.degree. 600 
71 47 43 61 37 47 36 88 55 
300 54 32 28 47 23 33 22 67 36 
3 32 12 6 27 4 13 4 38 13 
10 Min. Gel 62 61 57 44 65 55 69 101 121 
HOT ROLLED 150.degree. F. 16 HRS. 
Apparent Viscosity, cps 
47 25 21 32 17 26 18 60 36 
Yield Point 61 15 12 30 6 23 4 56 25 
(Lbs./100 sq.ft.) 
Fann.degree. 600 
93 49 43 64 34 51 36 120 71 
300 77 32 27 47 20 37 20 88 48 
3 46 8 4 20 1 14 1 51 15 
10 Min. Gel 44 26 20 33 16 25 17 63 55 
BOMBED 300.degree. F. 5 HRS. 
Apparent Viscosity, cps 
46 24 33 34 25 27 19 64 38 
Yield Point 56 13 31 34 14 23 9 58 29 
(Lbs./100 sq.ft.) 
Fann.degree. 600 
92 47 65 68 50 53 37 128 75 
300 74 30 48 51 32 38 23 93 52 
3 41 5 24 24 7 16 5 52 15 
10 Min. Gel 36 23 38 26 25 26 20 43 40 
__________________________________________________________________________ 
Reference 1: Contains 3.4% chromium. 
Reference 2: Contains 4.0% chromium. 
Reference 3: Chromiumfree iron complexed manganese lignosulfonate. 
As shown in Table I, the products of examples I-B, II-B and III-B show 
improved rheological properties compared to other chrome lignosulfonates 
and chrome-free lignosulfonates. These improvements are evidenced from a 
comparison of the rheological properties, particularly the yield points of 
the different products. It is important that the comparison without and 
with boron in each example be recognized. It is here that the invention is 
best exemplified. For example, in Example III-B the yield point is 17 
lbs/100 sq.ft. This yield point is identical to that of Reference 2 even 
though the raw sulfonated lignin material from which the additive of 
Example III-B was produced contained reducing sugars as well as 
polysaccharides. 
Various modes of carrying out the invention are contemplated as being 
within the scope of the following claims particularly pointing out and 
distinctly claiming the subject matter which is regarded as the invention.