CA1037468A - Soil conditioners and fertilizers from spent sulfite liquor - Google Patents

Abstract

Soil Conditioners and Fertilizers from Spent Sulfite Liquor Abstract of the Disclosure Spent sulfite liquor is converted into a nitrogen containing water insoluble product useful as a soil condi-tioner and fertilizer. The spent sulfite liquor is heated at a temperature of 170 to 260°C to form a partially pyrolyzed water insoluble material and the water insoluble material is then reacted with ammonia at a temperature of 170 to 260°C.

Description

. ~. D. Sears/F. W. Herrick 4-18 .

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This invention relates to nitrogen containing, water insoluble products prepared from spent sulfite liquor and to a process for their preparation.
Many attempts have been made to convert spent sulfite liquor, essentially a waste by-product from the preparation of wood pulp by the sulfite process, into useful products. Many of these attempts have involved investigations of the utility of these materials as soil additives to improve plant growth. Th~ investiga-tions have included pressure ammoniation of ~pont sulfite liquor at elevated terllperature to gi~e products with up to about 10~ nitrogen. ~ second route that has been investigated i~ the heatlng of spent sul~ite liquox~
with an alkaline substance such as calcium hydroxide to produce a soluble desulfonated lignin which is then am-moniated to obtain products containing 8 o 10% nitrogen which are utilizable as a fertilizer. However, none of these products has pro~ed commercially useful, either for reasons of cost or because of property deficiencies in the product.
It is an object of the present invention to pro-vide a nitrogen containing, water insoluble product rom ; spent sulfite liquors which is useful as both a soil ; conditioner and a fertiliæer.
It is an additional object of this invention to provide an economical process Eor convertin~ spent sul-fite liquor into a useful product.

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K. D. Sears/F. W. Herrick 4-18 ;
~3~7~6l~

The foregoing and other objects of the invention are achieved by heating spent sulfite liquor at a temper-ature of 170 to 260C to form a partially pyrolyzed water insoluble material and reacting said water insoluble material with ammonia at a temperature of 170 to 2~0C.
The products of the invention have been found to be use~ul both as soil conditioners and as slow release fertilizers.
"spent sul~ite li~uor" ISSL) as used hereln re~ers to spent sulfite llquor derived from the pulping of wood with a solution containing sul~urous acid and sodium or ammonium bisulfite. Such spent sul~ite liquors have a relatively low pH le.g. 1.5 to 4.0) and the lignin con-tained therein is considered to be in the fonm of ligno~
sulfonic acids and lignosulfonic acid salts of ammonium ; ox sodium. Such liquors also contain large quantities of reducing sugars, predominantly ma~nose and glucose, derived through hydrolysis of ~he carbohydrate fraction of the wood by the acidic cooking liquor. The spent sulfite liquors also include ammonium and sodium-base spent sul-fite liquors which were originally obtained by the acid-sulfite pulping o~ wood with sul~urou~ acid - bi~ul~ite solutions of other bases but which were subsequently converted to ammonium - or ~odium-base. Examples of the latter include ammonium - and sodium-base spent sulfite liquors prepared from calcium-base spent ~ulfite liquor by (1) treatment with ammonium or sodium ~ulfate or sul-fite under pH conditions such that the calcium i5 substantially precipitated, or 12) cation exchange.

K. D. Sears/F. W. Herrick 4-18 ~;37~i8 The process is carried out by first heating the SSL to form a partially pyrolyzed water insoluble material.
The semi-pyrolysis reaction is carried out at temperatures ranging from 170 to 260C in the open atmosphere with ap-propriate venting for times as little as 1/2 hours to as long as 12 houxs. Preferred operating conditions are temperatures from 220 to 240C and reaction times for from 1 to 6 hours. The semi-pyrolyzation produces a reaction product which is rom 75 to 97~ water insoluble. The water soluble portion may be leached away with water prior to the second 3tep of the process.
The insolubilized SSL resulting from the partial pyrolyzation is then reacted with ammonia at temperatures ranging from 170 to 260C for from 0.25 to 6 hours. Re-actions at 215 to 235C gave the highest organically com-bined nitrogen levels - from 6.3 to 9.1% for the product prepared from insolubilized ammonia-base SSL and from 3~2 to 6.5~ for the sodium-base counterpart. The reaction is carried out using weight ratios of ammonia to SSL solids of 0.25-2.0:1.0 (0.25 to 2 parts ammonia for each one part of 5SL solids). ~ighest nitrogen contents in the final product occur at ratios of 1.0-1.5:1, with a pre-ferred ratio being 1.1:1. There is normally excess ammonia present in the ammoniated product, and thus an excess o~ ammonia is desirable to force as much nitrogen as possihle into the product by the mass action effect.
The reaction may be carried out using either ammonia gas or a concentrated solution of ammonium hydroxide. The .. .. . . .

K. D. Sears/F. W. Herrick 4 18 ~3~
-- 5 ~

reaction with ammonia gas is somewhat more efficient than ammoniation with ammonium hydroxide solution. ~imes of reaction lower than 0.25 hours do not produce sufficient nitrogen incorporation while times in excess oE 6 hours incxease nitrogen content only slightly.
The foregoing reaction conditions are applicable to insolubilized SSL prepared from both ammonia- and sodium-base SSL. Somewhat higher organically combined nitrogen levels are obtained with ammonia-base SSL, un-doubtedly because oE khe presence of some organically combined nitrogen in the insolubilized ammonia-base SSL
product before the am~loniation react:Lon.
The ammoniated insolubilized products of the in-vention are useful both as soil conditioners and as ~low release fertilizers. Experiments with tomato plants at additive levels of 1 to 10~ of soil weight in diverse - soil types have indicated substankially increased fruit and tissue yields. The increased growth promotion is believed due principally to a soil conditioning efect ~o although the increased nitrogen availability contributes to the promotion of growth.
The invention will be better understood in con-nection with the following examples in which all parts and percentages are by weight, unless otherwise indicated.

Examples l_to 18 A 55 gallon drum of ammonia-base SSL was concen~
trated to a total solids content of 57~ having a viscosity o~ 6.4 poises. The concentrated SSL had the following analyses:

K. D. Sears/F. W. Herrick 4-18 ~B7~

Nitrogen (total) 2.4 Sulfur (total) 6.7 Sulfite (as S) .4 Sulfate (as S) 0.8 Free sugars (kotal) 28.0%
Total sugars (after hydrolysis) 33,2%
Am~onium lignosulfonate67.0%
~rhe concentrated SSL (60.0g, 34.2 g. ovan dried) was placed in each o~ three shallow aluminum pan3. The pans ware placod in an oven prehea~ed at 170C. Ini~ially there wa~
some foaming and frothing that could be controlled by puncturing the foam surface. At 6, 1~ and 24 hours inter-vals, a pan was removed and cooled. Insolubilized SSL
products were also made by open atmospheric heating at 200C and 230C under identical conditions.
Analyses of the insolubilized produ~ts of each of the heating experiments are set forth in Tables I, II and III for each of ~he temperatures used. Solubilities were determined by stirring 1.0 gram of the product in 100 ml of water for 1 hour and then filtering and drying.

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K. S. Sears/F. W. Herrick 4-18 ~3'7~

- TABLE I

Heating Time at Wt. Loss on Sol %N,S %S
ExampIe Condition Temp. ~r. Heating, ~ % of Product Loss *
1 open 6 6 20 2.5,5.3 26

2 " 12 15 13 2.5,5.2 33

3 " 24 1~ 10 2.6,5.0 36 * Corrected for weight shrinkage during heating.

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T~LE II

~Ieating Time at Wt. Loss on Sol %N,S %S
Example Condition Temp. Hr. ~Ieatin~ of Product Loss *

4 Open 6 13 10 2.6,4.7 39

5 " 12 18 5 2.7,4.0 51 ;6 " 24 19 5 2.9,3.5 5 * Corrected for weight shrinkage during heating.

TABLE III
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Heating Time at Wt. Loss on Sol %N,S ; %S
Example Condition Tem~ Hr. Heatin~! % % of Produat Loss *
7 Open 6 21 5 2.~,3.5 59 8 " 12 25 6 2.8,3.1 65 9 " 24 29 3 3.0~3.7 61 * Corrected for weight shrinkage during heating.

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- K. D. Sears/F. W. Herrick 4-18 7~

' It may be seen from Tables I to III that weight loss increased and water solubility decreased, with the use of increasingly more drastic conditions. The bulk of the weight loss is due to loss of carbohydrate mate-rial. Analysis of the Example 8 product (230~C for 12 hours) showed complete absence of sugars. The hea~ing process also ~erves to demethoxylate and desulfonate the SSL. The sulfur content is seen to become successively lower as temperature is increased. The % los~ of sulfur by weight is seen to be as high as 6S~ for Example 8.

Example~ 10 to 17 Insolubilized ammonia-base SSL prepared as set forth in Example 9 was placed in a stainless steel ve~sel and concen~rated NH40H was added (125 ml, 32.2g NH3~. ~he vessel was ~ealed and placed in an oven maintained at 210C.
The sealed vesse} was removed and cooled at time i~tervals ' of from 0~25 to 6 hours. Insoluble product was removed by ; filtration. The insoluble product was then disper~ed in 500 ml. of water and stirred for 1.5 hours before removal by filtration and thorough rinsing. The filtrates were discarded. The solid was dried in a vacuum oven at 50C
overnight. The same reaction was repeated at various time intervals at 200C and at 260C. Analyse~ were obtained o~
each of the reaction product~ and these are set forth in Table IV.

-- R. D, Sear~/FO WD Herrick ~-18 ~e;137~

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T~BLE IV

Solid Product __ _ a Temp., Time, Wt., ~ N % N
Example ~C hr. ~ b ~ N as NH3 Org. Comb.

230 - 6 72 9.4 0.3 9.1 11 230 3 75 8.4 0.5 7.9 12 Z30 1 7~ 7.8 0.7 7.1 13 230 0.5 80 7~7 0.8 G~9 1~ 230 0.25 77 6.6 0.3 6.3 1~ 200 3 80 7.3 1.0 6.3 16 200 1 84 7.5 0.7 6.~
17 260 oc 72 7.6 0.3 7.3 a Water insoluble.
b Based on weight of starting material (30 gO).
c As soon a~ 260C was reached, solution was cooled;
time to temperatureo 1O17 hour.

Table IV shows that the amount of organ cally com-bined nitrogen generally decreased with decreased reaction times, although the reaction pro~uct obtained by just heat-ing to 260C gave quite a substantial combined nitrogen level - 7.3%. On the other hand, yields of reaction product increased with decreasing time and thus short reaction times are desirable from a yield ~tandpoint. All factors considered, reactions at about ~2S to 235nC for relatively short times of from 1/4 to 1 hour would be the optimum time and temperature to prepars a high organically combined product ~about 7.0%
organically combined nitrogen).

K. D. Sears/F. W. Herrick 4-18 , - 10-.:

Exampl es 18 to 2 4 Additional reactions were carried out to determine the ef~ect of ammonia concentration on yield and nitrogen i~corporation. Examples 18 to 24 were repeated except that the ratio of ammonia concentration to SSL solids was varied.
- The reactions were carried out at 200 and 230C for 0.5 hours. Table V shows the analyses of these reaction products.
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T~BLE V

Solid Product , NH3 Wt. ~atio ~ N ~ N
Temp. Conc., of NH3:SSL Wt., as Org.
Example Cg. solids % % N NH3 Comb.
.' --- -- . . _ _ 18 23032.6 1.09:1.00 80 7.7 0.8 6.9 19 23016.3 0.5~:1.00 83 6.5 0.2 6.3 23010.9 0.36:1.00 88 6.0 0.3 5.7 - 21 2308.2 ~.27:1.0~ 88 6.2 0.4 5.8 22 2~016.1 0054:1.00 87 5.6 0.5 5.1 23 20010.7 0.36:1.00 86 5.6 0.5 5.1 24 2008.0 0.27:1.00 87 5.~ 0.5 4.9 Table V shows that at the lower ratios - Examples 19 through 24 - the amount of organicall~ combined nitrogen does not significantly vary. However, at levels above a ratio of about 1:1, a substantially higher combined nitrogen level occurred, principally because of the mass action effect.
Thus, best results are achieved with an excess of ammonia.

K. D. Sears/F. W. Herrick 4~18 ~03746B

Exam~le 25 The example illu~trate~ the preparation of gas ammoniated insolubilized ammonia~base SSL material.
Insolubilized ammonia-base material was prepared by heating concentrated ammonia-base SSL (110 g., 550 g.
o.d.) in a large metal pan for 6 hours at 230C. Initially ; there was frothing that could be controlled by puncturing the foam surface~ After 6 hours, the pan was removed and cooled. The product weighed 405 g. The insolubilized SSL
product w~s reduced ~o a more unifo~m particle ~ize in a Waring Blendor, The insolubilized product (200 g.) was placed in a stainless steel rocking autoclave that was sealed. Am-monia(93.5 g.), obtained from a large cylinder as liquid ammonia, was added to the autoclave (ratio of NH3: insolu-bilized SSL product of 0.47:1qO0). The unit was heated to 220C and maintained in the 220 to 230C ranqs for 1 hour;
a pressure of 1750 psi was a tained during the reaction.
After coo}ing and venting the excess gases, the solids were removed and placed in the hood and allowed to ~enti-later ~urther overnight. Weight o~ product recovered, 214 g. (108~ yield). The particle size of the material was furth~r refined in a Waring BlendorO

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- . K. D. Sears~F. W. Herrick 4-18 .-~93'7 The reaction product had khe following analysis:

,: , %
; Carbon 59.41 Hydrogen 5.11 Oxygen 21.7~
l~itrogen 9.31 Nitrogen (as Ammonia) 1.00 Nitrogen (Oxganically Bound) 8.31 Sul~ur 3.66 ; 10 Solubility ~Cold water, 1 g. in 100 ml.) 15.6 Density (g./cc.) 0.56 ... .
The.se results indicate a higher amount of immediately available nitrogen (as ammonia) and a higher water solubility than is normally obtained by reaction for equivalent times with aqueous ammonium hydroxide. Thus ~ the gas ammoniated pxoduct has more nitrogen in a readily available form for plant growth and would lead, for example, to a more immediate "greening-up" response after application to lawna.

Exam~les 26 to 29 Sodium-base SSL was used in these examples. The liquor was concentraked to a total solids content of 50.7~
and a viscosity of 2~4 poises. The concentrated sodium-base SSL had the following analyses:
., , ,: , . . . . . . . .

K. D~ Sears/F. W. Herrick 4-13 ' ~L~3 .: .

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Sodium 4.4 Sulfur (total) 5.1 Sulfite (as S) 0.03~
Sulfate (as S~ 0.09%
Total Sugars (after hydrolysis) 28.5~
Sodium ~ignosulfonate 64.0%

The concentrated sodium-base liquor ~59.2 g,, 30 g. O.D.) was placed in each oE two shallow aluminum pans after adjust~
ment of one o~ the lignin solutions to pH 1.9 with concen-trated sulfuric acid. The pans were allowed to sit one day to allow ~or some evaporation of moisture so foaming would be prevented during heating. The pans were placed in an oven preheated to 200C for 12 hours. Initially, there was some foaming and frothing that could be controlled by puncturing the foam surface~ After cooling, th~ remaining solids weighed 18.7 and 20.9 g. for the produc~ts derived from the unadjusted and adju ted pH solutions, respectively.
The solubilities of these two products was determined by stirring 2.000 g. in 200 ml. of water for 1 hours. The freeze dried flltrates were found to be light cream colored solids. An iclentical reactic)n was carried out at l2 hours for 230C. The results of these reactions are seen in Table VI.

K. D, SearsfF. W. ~errick 4-18 TABLE VI

% Na Wt. and S in Loss on ~ Na, % S Sol. Leached Example ~ Temp. ~leating ~total) % Fraction 26 1.9 230 28 6.0 5.1 221.5, 2.1 27 5.1 230 36 6~1 5.2 211.8, 2.Q
28 5.1 200 32 5.~ ~.8 22- , -29 1.9 200 24 5.3 4O~ 22- , -~xem~ 10 eo 36 A series o~ reactions of insolubilized sodium-base SSL products with ammonia were carried out by the same pro-cedure, varying only time and temperature.
Insolubilized product (30 g.) prepared by open atmospheric heating at 230C for 12 hours and leached with water to remove the soluble fraction (sodium sulfate~ was placed in a stainless steel vessel and concentrated ammoni~m hydroxide ~125 ml. 9 32.6 g7 NH3) was added. The vessel was sealed and placed in an oven and heated for 3 hours at 230~.
After cooling, the insoluble product was removed by filtra-tion~ It was then dispersed in water (500 ml.) and stirred for an additional 1.5 hours before remo~al by ~iltration and thorough rinsing. The filtrates w~re di~carded. The solid was dried in a vacuum oven ~50C) overnight. The results at various times and temperature are set forth in Table VII.

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K. D. Sears/F. W. Herrick 4-18 .

TABLE VI I

Solid Producta Temp., Time, Wt. % N % N
Example C hr. 96 b % N as NH3 Org. Comb.
.
230 6 75 6.80O3 6~5 31 230 3 76 6~90.7 6.2 32 230 1 77 5.00.7 4.3 . 33 230 0.5 75 5.20.7 4.S
34 230 0.25 73 ~.1 0~3 3.
200 3 70 3.80.6 3.2 36 260 oc 73 4.90.3 406 a. Water insoluble.
b. Based on weight of ~tarting material ~30 g.).
: c. As soon as 260C was reached, solution was cooled;
: 15 time to temperature: 1.17 hours.

Table VII indicates that higher levels of organically com-bined nitrogen occur when the reaction i~ carried out at 230~C ~han at 200C. The comblned nitrogen levels are lower for the product produced from sodium-base SSL than Prom the ammonium-base SSL. This undoubtedly can be at-tributed to the fact that about 3~ organically combined nitrogen i9 present in the insol~ilixed ammonia-base SSL
product before ammoniation. Table VII shows that the ef-fect of temperature on yield i~ only slight. All Pactors considered, optim~ times and temperatures for the ammonia-tion reaction with sodium-base product are seen to occur at from 3 to 6 hours at about 230C.

K. D. Sears~F. W. Herrick 4-18 .

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Examples 37 to 44 . . .
The same procedure as Examples 30 to 36 was followed at temperature of 200 to 230C for 0.5 hours, varying th~l~
amounts o ammonium hydroxide. The results are set forth in Table VIII.
TABLE VIII

Solid Product Wt. Ratio ~ N
Temp, Conc., of NH3:SSL Wt. ~ N Orcl.
Example C g Solids ~ ~ N ~ Comb.
.
10 37 230 32.6 1~09:1.00 75 5.2 0.7 ~.5 38 230 21.7 0.7~:1.00 7~ 3.g 0.3 3.~
39 230 16.3 0.54:1.00 74 4.0 0.3 4.1 ~0 230 10.9 0.36:1.00 72 3.3 0.3 3.0 41 230 8.2 0.27:1.00 73 3.1 0.4 2.7 15 42 200 16.3 0.54:1.00 71 2.8 0.4 2.4 ~3 200 10.9 0.36:1.00 71 2.6 0.4 2.~
44 200 8.2 0~27:1.00 71 2.3 -0.4 1.9 Table VIII indicates (as did Table V) that at the same tem-peratures, organically combined nitrogen levels do not differ a great deal at varying ammonia ratios below 1:1. However, at levels of about 1.1 to 1, the re~ulting product (Example 37) had a substantially larger combined nitrogen level than that obtained at ammonia ratlos o le~s than lsl~ The use of an excess o~ ammonia is therefore preferred, particularly if it is in a orm which may be recycled.

K~ D. Sears~F. WO Herrick 4-18 ~L03~46B
: - 17 -Tests were conducted to determine the ability of the products of the invention to promote growth of tomato plants. Experiments were carried out in two diverse soil types. Soils containing 5 and 10% by soil weight of ammoni-ated insolubilized ammonia-base SSL gave substantially increased fruit and tissue yields; soils containing 10%
gave fruit yields of 410 and 250~ over the controls and tissue yields of 152 and 184~ over the controls. The ef~
fect of the additives appears to be the promotion of a more favorable chemical interaction betwe~n th~ ~oil medium and the plant. ~ests hav~ ~hown that the SSL reaction pro-ducts of the invention release nitrogen slowly - slower than urea~orm fertilizers~ Since small amounts of nitro gent were released from the SSL products during the tomato plant tests, it is probable that pH reduction, improvement in soil physical characteristics and general soil condi-tioning eff~cts were the principal cause of enchanced growth. Increased nitrogen availability played a secondary role.

Claims (10)

We Claim

1. A process for preparing a nitrogen containing water insoluble product useful as a soil conditioner comprising heating spent sulfite liquor at a temperature of from 170 to 260°C to form a partially pyrolyzed water insoluble material, and reacting ammonia with said water insoluble material at a temperature of from 170 to 260°C.

2. The process of claim 1 in which the spent sul-fite liquor is ammonia-base.

3. The process of claim 1 in which the spent sul-fite liquor is sodium-base.

4. The process of claim 1 in which the heating step is at a temperature of 220 to 240°C.

5. The process of claim 1 in which the reaction with ammonia is at a temperature of from 215 to 235°C.

6. The process of claim 1 in which the reaction with ammonia is carried out with a ratio by weight of am-monia to water insoluble material of from 0.25 to 2 parts ammonia for each one part of water insoluble material.

7. The process of claim 6 in which said ratio in excess of ammonia is used.

8. The process of claim 1 in which the ammonia is in the form of aqueous ammonium hydroxide.

9. The process of claim 1 in which the ammonia is in the form of gaseous ammonia.

10. The product produced in accordance with the pro-cess of claim 1.