SU1720692A1 - Process for cleaning gases from sulfur dioxide - Google Patents

Abstract

The invention relates to the technology of utilization of S02 from gases, used in the metallurgical industry for the purification of gases containing up to 70% of S02, and allowing an increase in the degree of purification. Gases containing S02. treated with an aqueous suspension of products from hydrometallurgical processing of concentrates derived from copper-nickel ore. Purification is carried out at 25-100 ° C, the solid content in the suspension is 10-50 wt.% And the pH is 1.5-4. Products from hydrometallurgical processing from a series are used: oxidized pulp after autoclave leaching of pyrrhotite concentrate or matte, sulfur sulfide concentrate, sulfide concentrate, ferrous tailings of serosulfide flotation. The degree of purification from S02 is 99.6-100%. Spent sorbent used in the main production. 1 hp f-ly. 1 tab.

Description

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The invention relates to the utilization of sulfur dioxide from gases and can be used in the metallurgical industry for the purification of gases with a sulfur dioxide content of up to 70%.

Closest to the invention is a method of purifying gases from sulfur dioxide by treating it with a suspension, which is a mixture with water of crushed bake solid waste from the processing of copper-nickel ores in the form of slags or autoclave leaching tails with carbonates of alkaline earth elements. The latter is obtained, the specimen of these products at 870-1190 ° C and the mass ratio of waste and carbonates 1: (0.75-4). The ratio of liquid to solid in suspension is (14-30): 1.

The method has the following disadvantages:

-special preparation of the absorbent due to sintering with alkaline-earth elements, which entails significant energy costs for their extraction, transportation, sintering, grinding, preparation of the suspension;

-high intensity of the equipment due to the strong dilution of the suspension (g: t 14:30: 1);

- absorption of sulfur dioxide from a gas with a content of not more than 1.1% sulfur dioxide;

-absorbent is not used after utilization of sulfur dioxide;

-absorption absorption capacity depends largely on the ratio of the constituents in the sinter; without the addition of carbonates of alkaline earth elements, the degree of absorption is “7.9%;

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- The maximum degree of absorption of sulfur dioxide is 99.3%.

The purpose of the invention is to increase the degree of gas purification.

 Example. Cleaning is subjected to gas. containing 4.6% sulfur dioxide and 7.4% oxygen, the rest is nitrogen. As an absorbent of sulfur dioxide, a pulp of sulfur sulfide concentrate is used, which is a middling oxidative autoclave technology for the processing of pyrrhotite concentrate and contains,%: nickel sulfide 9.1: copper sulfide 1.4, iron sulfide 14.1, iron oxides 18.4, sulfur 50.6. The gas is passed at a rate of 3 l / min through an absorber (reactor) filled with absorbent pulp: 2 l of water and 800 g of solid (40%). The cleaning is carried out at a pulp temperature of 70 ° C. The degree of gas purification from sulfur dioxide at pH 2 is vl00%. During the purification process, the yield of the absorbent decreases and amounts to 624 g (78%) with the content,%: nickel sulphide 11.6, copper sulphide 1.8, iron sulphide 14.4, sulfur 69.4. The results of the experiment are presented in the table (experiment 1). The spent absorbent is sent to the technology from which it was borrowed, thereby increasing the productivity of the redistribution.

In experiments 2-4, gas cleaning is carried out similarly to experiment 1 at 25, 50 and 100 ° C, experiments 5-8 are similar to experiment 1 with a solid content of 50, 25, 10 and 5% in the pulp.

Experiments 9-13 were carried out similarly to experiment 1 with the content in the gas: op, 9 - 1.0% S02 and 21.7% 02, op. 10 - 6.2% S02 and 2% 02, op. 11 - 12% S02 and 4.4% 02, op. 12 - 22.7% 802. and 4.5% 02.op. 13-70.8% 50% 1.5% 02.

From the table it can be seen that with the help of the absorbent according to the invention, a high gas purification efficiency is achieved - 99.5-100% in the temperature range leading to the purification of 25-100 ° C from gas containing from 1 to 70% sulfur dioxide, when the solids content in the console is 10- 50 May. % and at pH values of 1.5-4. A decrease in the purification temperature below the specified limit reduces the productivity of the process due to a decrease in the absorption capacity of the absorbent, an increase (over 100 ° C) will require the use of special equipment operating under pressure and consequence, the appreciation of the process. When the content of solid in the pulp of the absorbent is less than 10 wt.%, The efficiency of gas cleaning decreases, and its increase by more than 50% is eco-. it is not profitable because it requires additional costs for thickening the products - the absorbents produced in

hydrometallurgical schemes. In addition, the transportation of the absorbent with a content of more than 50% solid causes certain difficulties associated with its settling in the pipeline. Decrease in size. A cleaning pH of less than 1.5 reduces the efficiency of gas cleaning, and an increase of more than 4 increases the cost of the process due to an increase in the amount of absorbent used and, accordingly, a decrease in its performance.

PRI me R 2. Cleaning is subjected to a gas containing 8.4% sulfur dioxide and 4.3% oxygen. Sulfide concentrate of oxidative autoclave technology from the processing of pyrrhotite concentrates and containing,%: nickel sulphide 15.4, copper sulphide 3.1, iron sulphide 47, iron oxides 18.0 is used as the sulfur dioxide absorbent. sulfur 4.9. The pulp of the concentrate containing 2 l of water and 500 g of solid (25%) with a temperature of 90 ° C is passed through an absorber (conditions are similar to example 1). The degree of gas purification from sulfur dioxide at pH 1.5 is 99.8%, the yield of absorbent is 81% (test 14). Spent absorbent material is sent to pyrometallurgy to release non-ferrous metals.

PRI me R 3. Purify is subjected to a gas containing 6.0% sulfur dioxide and 1.5% oxygen. Oxidized pulp from leaching of pyrrhotite concentrate, containing,%: nickel sulfide 1, copper sulfide 0.3, iron sulfide 15, iron oxides 56, sulfur 19, is used as the absorbent of sulfur dioxide. The solid pulp content is 800 g (40%). Gas cleaning temperature - 90 °. The degree of gas purification from sulfur dioxide at a pH of 1.5 is l / 100%, the yield of the absorbent is 49% (test 15). The spent absorbent is leached along with the starting pyrrhotite concentrate.

PRI me R 4. Purify gas containing 4.6% sulfur dioxide and 2% oxygen. As a sulfur dioxide absorbent, the flotation tails of the oxidative autoclave technology for the processing of pyrrhotite concentrates are used, containing,%: nickel sulfide 0.5, copper sulfide 0.15, iron sulfide 4.8, iron oxides 47.2, sulfur 2.5. The pulp content is 400 g (20%), the gas cleaning temperature is 100 ° C. The degree of purification of gas containing 4.6% of CO2 and 2% of 02 from sulfur dioxide at pH 1.5 is 99.6%, and the yield of absorbent is 14% (run 16). The spent absorbent is directed to co-leaching with the starting pyrrhotite concentrate.

PRI me R 5. Cleaning is subjected to gas. containing 5% sulfur dioxide and 2.5% oxygen. Pulp from oxidative autoclave leaching of matte, containing in solid,%: nickel sulfide 0.4, copper sulfide 0.1, iron sulfide 6.1, iron oxides 59, sulfur 1.9, is used as the absorbent D1 of sulfur oxides. g (30%). Gas cleaning temperature - 70 ° С. The degree of gas purification from sulfur dioxide at pH 1.5 is 400%, the yield of absorbent is 16% (experiment 17). The spent absorbent is fed to the leaching together with the original matte.

The proposed method allows to increase the degree of purification of gases from sulfuric anhydride to 99.6-100% versus 7.9% in the original method when using a slurry of the autoclave leaching tails. In addition, an absorbent is used, which is a middling of the technology and after applying it for disposal it is returned to the technology, from where

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Claims (2)

1. A method for purifying gases from sulfur dioxide by treating it with an aqueous suspension of products from hydrometallurgical processing of concentrates obtained from copper-nickel ore, characterized in that, in order to increase the degree of purification of gases, oxidized pulp is used as a specified product after leaching pyrrhotite concentrate or matte, or serosulfide concentrate, or sulfide concentrate, or iron tails of serosulfide flotation. 2. The method according to claim 1, wherein the gases are cleaned at a temperature of 25-100 ° C, the solid content in the suspension is 10-50% by weight and the pH value is 1.5-4. .f.