CN118291767A - Method for deeply separating arsenic and antimony from high-antimony smoke dust - Google Patents

Abstract

The invention discloses a method for deeply separating arsenic and antimony from high-antimony smoke dust. The invention reacts high antimony smoke dust with phosphoric acid solution; the reacted slurry is subjected to solid-liquid separation, the reaction product is antimony phosphate, the reacted liquid is used for treating a new batch of materials after being supplemented with phosphoric acid, the enriched arsenic is extracted after repeated circulation, and the liquid returns to the front-end working procedure after being supplemented with phosphoric acid after arsenic removal. The invention has the advantages of simple treatment process, convenient operation, low cost, no wastewater generation and the like, ensures the deep separation of arsenic and antimony in the smoke dust, and realizes the recycling of the arsenic. Solves the problems of high treatment cost, low efficiency, difficult separation of arsenic and antimony, large antimony loss, difficult recycling of arsenic and the like in the deep separation of arsenic and antimony from the current high-antimony smoke dust.

Description

A method for deep separation of arsenic and antimony from high-antimony smoke

Technical Field

The invention relates to the technical field of hydrometallurgical arsenic removal, and in particular to a method for deeply separating arsenic and antimony from high-antimony smoke.

Background technique

The traditional nonferrous metal smelting system inevitably produces a large amount of high antimony dust every year. Such dust generally contains 20% to 60% antimony and 20% to 40% arsenic. Antimony and arsenic mainly exist in the form of antimony trioxide and arsenic trioxide, respectively. The arsenic in high antimony dust hinders the comprehensive recycling of antimony and is not conducive to the green and sustainable development of the antimony industry.

At present, the arsenic removal treatment technologies for high arsenic antimony dust are mainly divided into two categories: pyrometallurgy and hydrometallurgy.

The basic idea of pyrometallurgy is to utilize the volatility difference between arsenic compounds and antimony compounds to volatilize the arsenic compounds in the material, while the antimony compounds remain in the material in a non-volatile form. However, this method is difficult to achieve deep separation of arsenic and antimony.

Compared with pyrometallurgy, hydrometallurgy has more cost advantages. Its basic idea is to use the different properties of arsenic compounds and antimony compounds, such as oxidizability and water solubility, to separate arsenic and antimony by controlling the pH, oxygen potential, temperature and other conditions of the leaching system. For example, the alkaline leaching process uses the properties of arsenic salts with high solubility and antimony salts with low solubility to separate arsenic and antimony, but it is extremely difficult to reduce the arsenic in the alkaline leachate to metallic arsenic. The acid leaching process uses various acidic solutions to leach and remove arsenic, such as hydrochloric acid, sulfuric acid and nitric acid, and then reduces the arsenic in the leachate to metallic arsenic for resource recovery. However, leaching under the acidic system has always had problems such as large antimony loss, high antimony concentration in the leachate, and difficulty in separating arsenic and antimony, which makes it difficult to reduce arsenic alone in the subsequent arsenic acid solution.

Therefore, the industry is in urgent need of a method that can efficiently separate arsenic and antimony in high-antimony smoke, and achieve arsenic enrichment and reduction in the leaching solution and a significant reduction in the antimony ion concentration.

Summary of the invention

The invention relates to a method for deeply separating arsenic and antimony from high-antimony smoke, which realizes the purpose of deeply separating arsenic and antimony from high-antimony smoke and enriching and reducing arsenic in leaching solution.

To achieve the above object, the present invention discloses a method for deep separation of arsenic and antimony from high-antimony smoke, comprising the following steps:

1) Leaching high-antimony dust with phosphoric acid to separate arsenic and antimony to obtain antimony phosphate and arsenic-containing solution;

2) The arsenic-containing solution is supplemented with phosphoric acid to continue leaching high-antimony dust, and the arsenic in the leaching solution is enriched after multiple cycles;

3) The arsenic-enriched liquid is subjected to arsenic reduction treatment to obtain metallic arsenic and de-arsenicated liquid, and the de-arsenicated liquid is supplemented with phosphoric acid to continue leaching high-antimony dust.

Preferably, the high antimony smoke is an antimony-rich and arsenic-containing material produced during the non-ferrous metal smelting process.

Preferably, the step 1) is:

A phosphoric acid solution is placed in a reaction container, and the phosphoric acid concentration is controlled to be 1-6 mol/L;

Add high antimony smoke to phosphoric acid solution at a liquid-to-solid ratio of 10:1 to 60:1 and stir, while controlling the reaction temperature to 30 to 90°C and reacting for 1 to 5 hours;

After the reaction, antimony phosphate and arsenic-containing solution are obtained by filtration and separation.

Preferably, the step 2) is:

When the phosphate ion concentration in the arsenic-containing solution is lower than 1 mol/L, the phosphate ion concentration is supplemented to be higher than 1 mol/L, and then the high antimony dust is continuously leached;

After multiple cycles, when the arsenic ion concentration in the arsenic-containing solution is higher than 0.15 mol/L, the circulation to enrich arsenic is stopped.

Preferably, the step 3) is:

The reaction temperature of the arsenic reduction condition in the arsenic enriched solution is 30-190° C., the reaction time is 1-5 hours, and the reducing agent includes one or more of zero-valent iron, zero-valent aluminum and hypophosphite.

Through the above technical scheme, arsenic and antimony in high-antimony smoke can be efficiently separated in depth, and arsenic reduction can be achieved to recover its resources; at the same time, the liquid after arsenic removal is a phosphoric acid solution, which can be returned to the front-end process for continued leaching after replenishing phosphoric acid, thereby achieving reusability.

The technical principles of the present invention are as follows:

When high antimony smoke is leached in an acidic system, Sb ₂ O ₃ and As ₂ O ₃ in the smoke react with the acid and dissolve into the solution, existing in the form of free As(Ⅲ) and Sb(Ⅲ). However, a large number of research documents show that the two are very easy to combine to form solid solutions in the form of (As,Sb) ₂ O ₃ and SbAsO _3. The solubility of these two solid solutions is low, making it extremely difficult to separate arsenic and antimony. Therefore, the reactions that may occur in the system are shown in the following equations (1)-(7):

As ₂ O ₃ + 3H ₂ O = 2H ₃ AsO ₃ (1)

2SbO ⁺ +2H ₃ AsO ₄ =Sb ₂ O ₃ ·As ₂ O ₅ +2H ₂ O+2H ⁺ (2)

SbO ⁺ +H ₃ AsO ₄ =SbOH ₂ AsO ₄ +H ⁺ (3)

4HAsO ₂ +H ₃ AsO ₄ +HSb(OH) ₆ =As ₄ ^III As ^Ⅴ Sb ^Ⅴ O ₁₁ ·7H ₂ O(4)

4SbO ⁺ +H ₃ AsO ₄ +HSb(OH) ₆ =Sb ₄ ^III As ^Ⅴ Sb ^Ⅴ O ₁₁ ·3H ₂ O+4H ⁺ (5)

_{Sb2O3 + 2HAsO2} ＝ _2SbAsO3 + _H2O (6)

SbO ⁺ +HAsO ₂ =SbAsO ₃ +H ⁺ (7)

Phosphorus, which is in the same family as arsenic and antimony, competes with arsenic. The concentration of phosphate in phosphoric acid solution is much higher than that of arsenic. Phosphate will preferentially combine with antimony in high-antimony dust to form insoluble antimony phosphate, thereby reducing or avoiding the formation of antimony arsenate products and achieving deep separation of arsenic and antimony in high-antimony dust. The reaction that may occur in the system is shown in the following formula (8):

_{Sb2O3 + 2H3PO4} ＝2SbPO4 _{+ 3H2O (} 8)

After leaching, the deep separation of arsenic and antimony in high-antimony smoke is achieved. After adding some phosphoric acid, the arsenic-containing solution can be returned to the front end for leaching until the arsenic ion concentration of the solution is enriched to a certain value. The arsenic is then reduced and the de-arsenicated phosphoric acid solution is recycled.

Based on the above technical ideas, the inventors proposed a method for deep separation of arsenic and antimony from high-antimony smoke.

Compared with the prior art, the present invention has the following advantages:

(1) The present invention is clean and efficient, low cost, simple to operate, low in energy consumption, requires no special equipment, is convenient for subsequent processing, and is easy to realize industrialization.

(2) The technical solution of the present invention uses phosphoric acid to directly leach high-antimony smoke, which can efficiently and deeply separate arsenic and antimony in the smoke.

(3) The arsenic-containing solution after leaching and the arsenic-removed solution of the present invention can be returned to the front-end process for further leaching after being supplemented with phosphoric acid, thereby realizing recycling. Therefore, it is environmentally friendly and does not generate waste gas, waste water, or waste residue.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG1 is a schematic flow diagram of a method for deep separation of arsenic and antimony from high-antimony smoke proposed by the present invention;

FIG2 is a SEM image of antimony phosphate obtained in Example 2;

FIG. 3 is an EDS graph of antimony phosphate obtained in Example 2.

Detailed ways

The present invention will be further described below in conjunction with the accompanying drawings. It should be noted that the following embodiments are based on the present technical solution and provide detailed implementation methods and specific operating processes, but the protection scope of the present invention is not limited to these embodiments.

The contents of the main components of different high antimony smoke vary greatly. The samples of Examples 1-2 were collected from a non-ferrous metal smelter in my country, and their main components are shown in Table 1:

Table 1

Embodiment 1:

Take 50g of high antimony smoke, add phosphoric acid solution at a liquid-solid ratio of 30:1, control the concentration of phosphoric acid solution to 1mol/L, 2mol/L, 3mol/L, 4mol/L, 5mol/L, and 6mol/L, respectively, maintain the solution temperature at 90℃, and stir for 3h at normal pressure. The arsenic concentrations of the liquid samples taken for testing were 4.237g/L, 5.144g/L, 5.315g/L, 5.316g/L, 5.316g/L, and 5.316g/L, and the leaching rates of arsenic were 79.70%, 96.75%, 99.97%, 99.99%, 99.99%, and 99.99%, respectively; the antimony concentrations were 96.47mg/L, 60.59mg/L, 45.71mg/L, 38.78mg/L, 39.97mg/L, and 40.68mg/L, and the leaching rates of antimony were 0.45%, 0.23%, 0.21%, 0.18%, 0.19%, and 0.19%, respectively.

Embodiment 2:

Take 50g of high antimony smoke, add 4mol/L phosphoric acid solution at a liquid-solid ratio of 30:1, control the reaction temperature to 30℃, 45℃, 60℃, 75℃ and 90℃, and stir for 3h at normal pressure. The arsenic concentrations of the liquid samples tested were 1.877g/L, 3.342g/L, 3.927g/L, 4.880g/L, 5.316g/L, and the arsenic leaching rates were 35.31%, 62.85%, 73.87%, 91.78%, and 99.99%, respectively; the antimony concentrations were 54.12mg/L, 59.21mg/L, 48.23mg/L, 41.86mg/L, and 38.78mg/L, and the antimony leaching rates were 0.25%, 0.28%, 0.23%, 0.20%, and 0.18%, respectively. When the reaction temperature is 90°C, the SEM image of the obtained leached residue is shown in FIG2 , and the EDS analysis result is shown in FIG3 .

Embodiment 3:

The sample is high antimony smoke phosphoric acid leaching solution, and its main components are shown in Table 2:

Table 2

Take 100ml of leaching solution, use iron as a reducing agent, control the iron-arsenic molar ratio to 0.8, 1.6, 2.4, 3.2, 4.0, and react at a reaction temperature of 150°C for 5h. The arsenic concentrations of the liquid samples tested were 7.012g/L, 4.167g/L, 0.258g/L, 0.052g/L, and 0.006g/L, and the arsenic reduction rates were 52.91%, 72.02%, 98.27%, 99.65%, and 99.96%, respectively.

For those skilled in the art, various corresponding changes and modifications can be made according to the above technical solutions and concepts, and all of these changes and modifications should be included in the protection scope of the claims of the present invention.

Claims (5)

1. A method for deep separation of arsenic and antimony from high-antimony smoke, characterized in that it comprises the following steps: 1) Leaching high-antimony dust with phosphoric acid to separate arsenic and antimony to obtain antimony phosphate and arsenic-containing solution; 2) The arsenic-containing solution is supplemented with phosphoric acid to continue leaching high-antimony dust, and the arsenic in the leaching solution is enriched after multiple cycles; 3) The arsenic-enriched liquid is subjected to arsenic reduction treatment to obtain metallic arsenic and de-arsenicated liquid, and the de-arsenicated liquid is supplemented with phosphoric acid to continue leaching high-antimony dust. 2. A method for deep separation of arsenic and antimony from high-antimony smoke according to claim 1, characterized in that the high-antimony smoke is an antimony-rich arsenic-containing material produced in the process of non-ferrous metal smelting. 3. The method for deep separation of arsenic and antimony from high-antimony smoke according to claim 1, characterized in that the step 1) is: A phosphoric acid solution is placed in a reaction container, and the phosphoric acid concentration is controlled to be 1-6 mol/L; Add high antimony smoke to phosphoric acid solution at a liquid-to-solid ratio of 10:1 to 60:1 and stir, while controlling the reaction temperature to 30 to 90°C and reacting for 1 to 5 hours; After the reaction, antimony phosphate and arsenic-containing solution are obtained by filtration and separation. 4. The method for deep separation of arsenic and antimony from high-antimony smoke according to claim 1, characterized in that the step 2) is: When the phosphate ion concentration in the arsenic-containing solution is lower than 1 mol/L, the phosphate ion concentration is supplemented to be higher than 1 mol/L, and then the high antimony dust is continuously leached; After multiple cycles, when the arsenic ion concentration in the arsenic-containing solution is higher than 0.15 mol/L, the circulation to enrich arsenic is stopped. 5. The method for deep separation of arsenic and antimony from high-antimony smoke according to claim 1, characterized in that the step 3) is: The reaction temperature of the arsenic reduction condition in the arsenic enriched solution is 30-190° C., the reaction time is 1-5 hours, and the reducing agent includes one or more of zero-valent iron, zero-valent aluminum and hypophosphite.