CN1676637A

CN1676637A - Pollution-free arsenic alkali slage treating technique

Info

Publication number: CN1676637A
Application number: CNA2004100230550A
Authority: CN
Inventors: 仇勇海; 钟宇
Original assignee: Guangxin Smeltery Co Ltd Yunan County; Central South University
Current assignee: Guangxin Smeltery Co Ltd Yunan County; Central South University
Priority date: 2004-03-31
Filing date: 2004-03-31
Publication date: 2005-10-05
Anticipated expiration: 2024-03-31
Also published as: CN100402680C

Abstract

This invention is non-pollution arsenic alkali slag treatment technology. This invention relates to the environmental protection method of colored metal metlting. This invention leads the CO2 gas into the de-antimonization leaching liquor during de-alkali procedure, the carbonate filtered is washed and then returns to antimony melting. The water agent of technique procedure of this invention is looped recycling without waste water; antimony refined ore, carbonate returning antimony melting; arsenic sulfide, barium sulfate are the products to be sold without new slag; the little hydrogen sulfide waste gas during the de-arsenic procedure is absorbed by the NaOH solution and the absorbing agent can return to the de-arsenic system. The antimony recycling ratio is up to 99%; the plumbum recycle ratio is near 100%; arsenic leaching ratio surpasses 90%, alkali leaching ratio surpasses 97%, and sodium sulfate leaching ratio is near 100%. The flow is simple, and the operation is easily controlled, the investment is low and the economic and environmental benefits are apparent.

Description

Pollution-free arsenic alkali residue treatment technology

The invention relates to the environment protection technology of non-ferrous metal smelting, in particular to a technical method for pollution-free treatment of arsenic alkali slag produced by antimony alkali refining.

As alkaline residue produced in antimony alkaline refining in the background art, the main material components are as follows: sodium antimonite, lead oxide, sodium arsenate, sodium arsenite, sodium carbonate, sodium bicarbonate and sodium sulfate. Since sodium antimonite, sodium antimonite and lead oxide are insoluble in water, one can separate them from soluble sodium arsenate, sodium arsenite, sodium carbonate, sodium bicarbonate and sodium sulfate. The problems of recycling and comprehensive utilization of toxic sodium arsenate and sodium arsenite, sodium carbonate, sodium bicarbonate and sodium sulfate have not been solved well for a long time. If the toxic sodium arsenate and sodium arsenite can be separated from other soluble sodium salts, better economic benefit and environmental benefit can be produced.

CN00131557.9 discloses a method for treating arsenic alkali slag in antimony smelting, which adopts SO₂Or treating the alkali liquor by sodium thiosulfate under the condition that the pH value is adjusted to be less than 5 by acid, and precipitating arsenic sulfide with the arsenic content of 20%. In the method, a large amount of sodium carbonate is necessarily converted into sodium sulfate by treating the alkali liquor with sulfuric acid or sulfurous acid. The sodium sulfate has low yield value and high energy consumption for recovering the sodium sulfate; if lime emulsion is adopted to further treat the liquid after arsenic removal, calcium sulfate can be precipitated, and the treatment of a large amount of alkaline liquid after calcium removal is problematic.

Men,taimen, etc. have proposed a method for treating arsenic-alkali residue by using calcium hydroxide to precipitate calcium arsenate [ see: the new technology for treating antimony-arsenic-alkali smelting slag, non-ferrous metal (smelting), 1999(5), 11-14, by men, etc. Because the solubility of calcium carbonate is far less than that of calcium arsenate, a large amount of sodium carbonate in the alkali liquor must be converted into calcium carbonate, and because the calcium-arsenic ratio is up to 10 during treatment, arsenic alkali residue is treated, but a large amount of arsenic-calcium residue is generated at the same time, which is not beneficial to environmental protection.

The invention aims at the problems of the method, provides a pollution-free arsenic alkali residue treatment technology, and improves the economic benefit of enterprises by recycling antimony concentrate and sodium carbonate; the problem of environmental pollution caused by arsenic alkali slag in antimony smelting is solved by recycling arsenic sulfide.

The invention relates to a pollution-free arsenic alkali residue treatment technology, which comprises the working procedures of antimony removal, dealkalization, arsenic removal and sodium removal,

1. in the antimony removal process, arsenic alkali slag is crushed to be below 10 mm, stirring leaching is carried out at the temperature of more than 85 ℃, antimony concentrate produced after filtering is washed by hot water, and the antimony concentrate returns to antimony smelting; and (4) leading the leaching solution to enter a dealkalization process.

2. The dealkalization procedure is to introduce carbon dioxide gas into the antimony-removed leaching solution and stir at the temperature of 20-50 ℃ for dealkalization. Washing the carbonate produced after filtering with warm water, and returning the carbonate to antimony smelting; and (5) leading the dealkalized solution to enter a dearsenization process.

The carbon dioxide gas is dissolved in water to form carbonic acid, the carbonic acid reacts with sodium carbonate to form sodium bicarbonate, and the solubility of the sodium bicarbonate is far less than that of the sodium carbonate, so that the aim of removing most of the sodium carbonate in the alkali liquor can be achieved.

3. In the arsenic removing process, according to the arsenic content, a theoretical amount of sodium sulfide solution is added into the dealkalized solution, sulfuric acid is added, the pH value of the solution is controlled to be 2-5, the solution is stirred at the temperature of 50-60 ℃ for arsenic removal, and sulfide of arsenic is precipitated. Washing the arsenic sulfide produced after filtering with warm water, and drying to obtain an arsenic product raw material; and (5) performing sodium removal on the arsenic removal liquid.

4. Sodium removal procedure supersaturated barium hydroxide solution is added into arsenic removal liquid at normal temperature to separate out barium sulfate precipitate. Washing the barium sulfate produced after filtering with warm water, and drying the barium sulfate to obtain a final product; returning the sodium-removed solution to the antimony-removing process.

The invention has the following advantages: in the technological process of the invention, the aqueous solution iscirculated in a closed loop, and no wastewater is discharged; antimony concentrate and carbonate are returned to antimony for smelting; arsenic sulfide and barium sulfate are sold as products; no new waste residue is generated; a small amount of hydrogen sulfide waste gas generated in the arsenic removal process is absorbed by a sodium hydroxide solution, and the absorption liquid can be returned to an arsenic removal system for use. The recovery rate of antimony reaches 99 percent; the lead recovery rate is close to 100 percent; the arsenic leaching rate exceeds 90 percent, the alkali leaching rate exceeds 97 percent, and the sodium sulfate leaching rate approaches 100 percent. The content of carbonate can reach 96%, and the arsenic content of washed carbonate can be controlled to be about 1%. The arsenic content in the arsenic-removed slag can reach 37 percent, and the arsenic sulfide content is 77 percent. The recovery rate of arsenic in the leaching solution reaches 99 percent. New waste gas, waste water and waste residue are not generated in the arsenic-alkali residue treatment process; the process flow is simple, the operation condition is easy to control, and the equipment investment is low; the economic benefit and the environmental benefit are more obvious.

Description of the drawings fig. 1: the invention is a process flow diagram.

Detailed Description

1. The arsenic alkali slag raw material of a certain smelting plant is adopted to carry out leaching antimony removal industrial test. The results of the raw material analysis are shown in table 1.

TABLE 1 analysis results (%)

Sb	Pb	As	Na₂CO₃	NaHCO₃	Na₂SO₄
Sb	Pb	As	Na₂CO₃	NaHCO₃	Na₂SO₄	19.69	26.43	11.01	17.66	2.88	6.48

Sieving arsenic alkali residue (granularity less than 8 mm) crushed by the mouth of the tiger, and directly feeding into an extraction kettle. The volume of the aqueous leaching kettle solution was 5 cubic meters. 2 tons (dry basis) of arsenic slag are added. The liquid-solid ratio was 2.5. Leaching for 2 hours. The temperature is about 85 ℃.

The results of the industrial tests for leaching arsenic alkali residue are shown in tables 2 and 3.

TABLE 2 Industrial test arsenic slag leach results (g/L)

Na₂CO₃	NaHCO₃	Na₂SO₄	Sb	Pb	As
Na₂CO₃	NaHCO₃	Na₂SO₄	Sb	Pb	As	82.02	3.14	21.54	2.39	0.00	36.71

TABLE 3 antimony concentrate composition analysis results (%)

Sb	Pb	As	Na₂CO₃	NaHCO₃	Na₂SO₄
Sb	Pb	As	Na₂CO₃	NaHCO₃	Na₂SO₄	32.69	53.71	1.06	0.52	0.00	0.00

According to the analysis results of the arsenic alkali slag raw material and the antimony concentrate material in the table 1 and the table 3, the recovery rates of antimony and lead and the leaching rates of arsenic and alkali in the industrial test are shown in the table 4:

TABLE 4 recoveryof antimony and lead and leaching rate of arsenic and alkali (%)

Recovery rate		Leaching rate
Recovery rate		Leaching rate				Sb	Pb	As	Na₂CO₃	NaHCO₃	Na₂SO₄
98	100	91.1	97.1	100	100	Sb	Pb	As	Na₂CO₃	NaHCO₃	Na₂SO₄

Adding the solution after antimony removal leaching into a reaction kettle, and introducing carbon dioxide gas at the temperature of 20-50 ℃. Taking filtrate for analysis of Na₂CO₃、NaHCO₃And (4) content. Na (Na)₂CO₃The content is close to zero as the end point of decarbonation.

The results of the decarbonation roasting of the arsenic caustic sludge leachate are shown in table 5.

Table 5 carbonate baking results (%)

Na₂CO₃	NaHCO₃	As	(Na₂HAsO₄)
Na₂CO₃	NaHCO₃	As	(Na₂HAsO₄)	93.84	2.17	1.60	(4.0)

As can be seen from Table 5, the carbonate content reached 96%.

The washed and dried carbonate can be returned to an antimony smelting plant for alkaline refining of antimony. The arsenic content of the washed carbonate can be controlled to be about 1 percent.

The pH 4 was selected as the end point of the arsenic removal solution, and the results of the analysis of the arsenic content in the arsenic removal solution are shown in table 6:

TABLE 6 dearsenification results (g/L) of the post-dealkalization liquor

As	Sb	Pb	Na₂SO₄
As	Sb	Pb	Na₂SO₄	0.15	0.13	0.0008	113.44

The results of the analysis of the washed arsenic sulfide are shown in Table 7:

TABLE 7 arsenic sulfide analysis results (%)

Sb	Pb	As	Na₂CO₃	NaHCO₃	Na₂SO₄
Sb	Pb	As	Na₂CO₃	NaHCO₃	Na₂SO₄	1.70	0	37.0	0	0	0

The arsenic-rich slag produced by arsenic removal is a popular raw material for professional arsenic smelters.

The treatment of the sodium sulphate solution with barium hydroxide is very easy, and the sodium sulphate is completely converted to barium sulphate in only half an hour.

Claims

1. A pollution-free arsenic alkali residue treatment technology comprises the processes of antimony removal, dealkalization, arsenic removal and sodium removal, and is characterized in that:

in the dealkalization process, carbon dioxide gas is introduced into the antimony-removing leaching solution, stirring is carried out at the temperature of 20-50 ℃ for dealkalization, carbonate produced after filtration is washed and then returned to antimony smelting, and the dealkalized solution enters the dearsenization process;

in the arsenic removing process, adding a theoretical amount of sodium sulfide solution into the dealkalized solution according to the arsenic content, adding sulfuric acid, controlling the pH value of the solution to be 2-5, stirring at the temperature of 50-60 ℃ to remove arsenic, precipitating arsenic sulfide, and allowing the dearsenized solution to enter the sodium removing process.