SU1038278A1 - Method for producing elemenaty sulfur - Google Patents

Abstract

A method for producing sulfur element from aqueous solutions of inorganic sulfur compounds by treating them with hydrogen sulfide in the presence of a catalyst, characterized in that, in order to simplify the process, a solution of oxides or hydroxides of aluminum or silicon in fluorine-hydrofluoric acid with the concentration of these elements 1 "2 10 mol / l and the process is carried out at a pH of 4.0-6.0 and a temperature of 20-8O C.

Description

(L

with

at

v

I

with

a The invention relates to catalytic methods for the neutralization of solutions containing inorganic sulfur compounds in the form of ammonium or alkali metal salts, such as: sulfites, thiosulfates, bisulfites, polythionates formed by absorption of SO, by aqueous sorbents from Clach gas of Claus installations, metal exhaust gases production facilities, energy combustion plants for sulfur-containing fuels, as well as for the disposal of other water streams, which are disposed of in industrial enterprises for the purpose of recycling chamois, and for POSSIBILITY using the purified aqueous stream for the same purposes. Quite a number of methods have been developed for extracting sulfur from solutions of no-absorption 90/2 using as a reducing agent. 1, a method for producing sulfur and sulphite-containing aqueous solutions is known by treating them with an agent. at elevated temperatures with the formation of thiosulfates, which are then reduced, for example with hydrogen sulfide, to polysulfides at 100370 ° С and an elevated pressure of up to 48 atm, followed by their decomposition with the formation of sulfur | 1. The disadvantage of this method is the necessity of carrying out the step of reducing thiosulfates under elevated pressure. The closest to the present invention is a method for treating a thiosulfate solution with hydrogen sulfide, in which ammonium thiosulfate saturated with ammonium (or alkali metal, alkaline earth metal sludge) reacts with hydrogen sulfide (the mole ratio to thiosulfate is chosen from a range of from 3.5: up to 10: 1.0 at 175-350 ° C, a pressure of 7-352 atm and a contact time of 0.6-60 minutes Moreover, the method is carried out both without a catalyst and in the presence of a catalyst, which is used as metal oxide or sulfide variable valence fishing of groups VI and VII, nan Burned on activated carbon or refractory oxides. The stream treated with hydrogen sulfide containing a polysulfide compound and unreacted hydrogen sulfide is rapidly cooled to 25-150 ° C. At the same time, the sulfides are destroyed and elemental sulfur is released.If the temperature of the cooled solution is above the melting point of sulfur V / 11 s , then sulfur is separated in the form of a melt, or if T, then sulfur in the form of a solid phase is separated from the solution by separation without understanding the pressure. Thereafter, the sulfur-free stream is reduced by pressure to atmospheric pressure into an aqueous stream having a substantially reduced thiosulfate content, and a gas stream containing unreacted hydrogen sulfide 23. The disadvantages of the known method include the following: all stages of the process are carried out at a significantly elevated pressure and high temperature, a multi-stage process, i.e. thiosulfate is converted to polysulfides, and then carried out from the destruction to form elemental sulfur. The purpose of the invention is to simplify the process. The goal is achieved by the described method of obtaining, which involves treating aqueous solutions of inorganic sulfur compounds with hydrogen sulfide at 20-80 ° C and pH 4.06, 0 and in the presence of a catalyst, which is a solution of oxides or hydroxides of aluminum or silicon in hydrofluoric acid These elements I-lO 210 ol / l and the process is carried out at a pH of 4.0-6.0 and a temperature of 20-80s. The choice of the temperature range is due to the fact that the actual flows formed at the production have a temperature of about 100 ° C, therefore, to maintain the temperature in these limits no additional energy is required to cool the solution (below heating (above 80 ° C; choice of pH range the solution is due to the fact that at a pH of less than 4.0 there are limitations on the choice of material dp manufacturing apparatuses due to severe corrosion in an acidic environment, at pH greater than 6.0, the reaction proceeds according to a different scheme with the formation of polysulfides. and the reaction of reduction of Lenin without a catalyst under the proposed conditions in a solution containing sulphite, bisulphite, thiosulphate and proteion politionates the following main reactions: with 2HSO bisulphite, + - ZHjO.CD with sol-f- H, j, HjO sulphite, (z) with ZHjS + + (3) thiosulfate with S ,, ZN, 2S, (1). + 3S + ZN, 0. (5, etc.) reactions, 1,2,4 and 5 pass quickly high speed, and reaction 3 is slow, and is limiting, i.e. the main problem in reducing the compounds listed above is the reduction of thiosulfate. In connection with this, a proposed effective homogeneous catalyst has been developed. The catalyst solution is prepared from silicon or aluminum oxides or hydroxides by dissolving them in plasmic acid as follows. Sample A. 100 ml of 35% hydrofluoric acid are placed in a fluoroplastic or polyethylene container and cooled to O ° C. Then SiO-j is added in small portions. so that the temperature of the solution does not exceed. After adding 0.1092 g С1.82 10 mol) SiOa capacity is hermetically sealed and the solution is left to stand without cooling for at least 12 hours. The solution thus obtained has a silicon concentration of 1.8210 mol / l. Sample B. 0.1420 g (1.82-10 mol of AB (OH) is dissolved. In 100 ml of 35% by the procedure described for the preparation of sample A. The resulting solution of the catalyst has an aluminum concentration of 1 , 82 10 mol / l. In a similar way, catalyst solutions were prepared from aluminum oxide and silicon hydroxide. The concentration of the main component in the catalyst solution (silicon, aluminum V should not exceed 0.35 mol / l. The solutions thus obtained are used as catalytic additions to contact solutions containing sulfur compounds that are reconstituted hydrogen sulfide recovery The recovery of solutions containing inorganic sulfur compounds with hydrogen sulfide is studied in a bulk static installation with an oscillating thermostatted glass reactor at atmospheric pressure. P aa oroRoS due to the instability of the reduction rate during the experiment due to a decrease in the concentration of the starting sulfur containing compounds in the solution , as a measure of catalytic activity, the average absorption rate of hydrogen sulfide is 1 l of the contact solution from the initial moment until the moment, corresponding to 1/3 of the total absorption. Ammonium acetate buffers are used to create the appropriate pH of the solution. Buffer solutions are prepared as follows: 3 n. Acetic acid solution was added. solution H. HE and diluted with distilled water. Table 1 presents the test of contact solutions with different catalysts at their various concentrations. The experiments were carried out under the following conditions: Top BO-S, 0 P. 660 mm Hg. Table 2 presents the test of contact solutions at different temperatures. In all examples, pH 5.0. Table 3 presents the test of contact solutions at various pH values of the solutions. The experiments were carried out at a temperature of 50 ° C at 660 mmHg. Table 4. shows the test solutions, which include various inorganic sulfur-containing compounds. Thus, as can be seen from Tables 1-4, it follows that the catalytic reduction of sulfur-containing compounds in solution takes place: in one stage without the formation of polysulfide intermediates; at a temperature substantially below the temperature of the prototype process and does not require additional energy costs at the atmospheric pressure, which significantly simplifies instrumentation in an environment close to neutral, which also does not impose additional requirements on the materials used for the manufacture of devices; in the presence of small amounts of the catalyst, which is easy to prepare. and using cheap and available compounds for this purpose (, etc.), whereas in the prototype process, catalysts / including components such as Pt, P1, Cc Mo, etc. are used.

for compare (NH) 0, eni) (NH4.)

SiOj,

HF

(

Af (OH) j

HF

(NH)

for comparison 5

(, five

SiOi

At (OH)

HF

(NH4,

At (OH) j

HF

(S., 0,

Sioj

HF

(NH4) AO

SiO-j

Hf

(NH ,, 0,. (NH), SiO, Si O HF

Table

To

9,6vlO 30,8-101-10

si

55,4aor

AE

2.0-1050, 6-100,

Si + AP

0,

five,

-3

Aft

no

4.68 .10. 10Si

, g

4.9 10

uh

-ten

Si

table 2

0.85-10

20 2,710

20

(NH4.) 2.SjO

(m)

SiOa HF

(NH4) 4SaO (NH) S.O

.

HF

(U (NH) SiOi HF

(NH, 4)

(Nn4)

Sio

HF

 ° i

Nai

SiOi

HF

Continued table. 2

2.0 .10

50 6.2-10

50

-S

18,6-10

80

-4 73,210

80

T a b L H C a

1.1-10

6.0 6.0-10

6.0

9.6-105, 0 30.810

5.0

3.0. ten

4.0 12.0. 10 4,0

ъ

.Table 4

Claims (1)

METHOD FOR PRODUCING ELEMENTARY SULFUR from aqueous solutions of inorganic sulfur compounds by treating them with hydrogen sulfide in the presence of a catalyst, characterized in that, in order to simplify the process, a solution of oxides or hydroxides of aluminum or silicon in hydrofluoric acid with a concentration of these elements 1 · 10 is used * 4-2'U '^ mol / l and the process is carried out at pH = 4.0-6.0 and a temperature of 20-80 ° C. 1Λ 00 b * 4 os>