Method for cooperatively treating fluorine-containing waste acid by using copper smelting tailings and calcium hydroxide

Abstract

The invention relates to a method for cooperatively treating fluorine-containing waste acid by using copper smelting tailings and calcium hydroxide, and belongs to the technical field of waste acid treatment.The method comprises the steps that smelting slag generated through smelting and blowing procedures in the copper smelting process is taken and subjected to slow cooling, crushing, copper flotation and iron magnetic separation process treatment, and then tailings are obtained; the tailings and water are put into a stirring bin and stirred for 1-3 h at the temperature of 45-50 DEG C and the speed of 60-100 r / min, and slurry is obtained and stored at the constant temperature of 42 DEG C for use; putting the slurry and the waste acid into a stirring bin, stirring for 10-20 minutes at the speed of 10-30 r / min, and stirring for 10-20 minutes at the speed of 10-30 r / min after 30 minutes; and adding calcium hydroxide and detonation oxygen into the prefabricated material, neutralizing until the pH value is 8-8.5, stirring for 1-3 hours at 120-150r / min, and carrying out solid-liquid separation to obtain reuse water with the arsenic content less than or equal to 0.5 mg / L and the fluorine content less than or equal to 5mg / L. According to the method, the industrial waste copper smelting tailings are fully utilized and converted into the fluorine-containing waste acid treating agent, arsenic and fluorine in waste acid can be efficiently removed, and deep removal of arsenic and fluorine in waste acid can be achieved by optimizing the treatment process and parameters.

Description

Technical Field

[0001] The invention belongs to the technical field of waste acid treatment, and specifically relates to a method for collaboratively treating fluorine-containing waste acid by using copper smelting tailings and calcium hydroxide. Background Art

[0002] In the copper smelting process, due to the complex composition of copper ore, a large amount of fluorine-containing waste acid will be produced during the smelting process. If these waste acids are directly discharged, they will not only cause serious pollution to the environment, but also pose a threat to human health. Therefore, the development of an efficient and environmentally friendly waste acid treatment method is of great significance to the sustainable development of the copper smelting industry.

[0003] Copper smelting tailings are the smelting slag produced by the smelting and blowing processes in the copper smelting process, and then processed by slow cooling + crushing + copper flotation + magnetic iron separation. Its main components include iron, silicon and other elements. Copper smelting tailings are qualitatively classified as bulk solid waste;

[0004] The sulfidation method is one of the commonly used waste acid treatment methods in the copper smelting industry. This method converts arsenic and other heavy metals in the waste acid into insoluble sulfide precipitates by adding sodium sulfide (or sodium hydrosulfide) to the waste acid. The precipitate is then separated by filtration and the like, thereby achieving the purpose of removing arsenic and other heavy metals in the waste acid. However, the arsenic content in the waste acid after treatment by this method is 30 mg / L, and the fluorine content is below 1000 mg / L, and it needs to be reused after secondary treatment. Summary of the invention

[0005] The purpose of the present invention is to provide a method for co-treating fluorine-containing waste acid by using copper smelting tailings and calcium hydroxide in order to solve the above problems.

[0006] The present invention achieves the above-mentioned purpose through the following technical solutions:

[0007] The present invention provides a method for synergistically treating fluorine-containing waste acid by using copper smelting tailings and calcium hydroxide, comprising the following steps:

[0008] Step S1, taking the smelting slag produced by the smelting and blowing processes in the copper smelting process, and subjecting it to slow cooling, crushing, copper flotation, and magnetic iron separation processes to obtain tailings;

[0009] Step S2, putting the tailings and water into a stirring bin, stirring at 45-50°C and 60-100 r / min for 1-3 hours to obtain a slurry, and storing it at a constant temperature of 42°C for later use;

[0010] Step S3, placing the slurry and the waste acid into a stirring bin, stirring at 10-30 r / min for 10-20 min, and stirring at 10-30 r / min for 10-20 min after an interval of 30 min to obtain a prefabricated material;

[0011] Step S4, adding calcium hydroxide + explosive oxygen to the prefabricated material to neutralize to pH = 8-8.5, stirring at 120-150r / min for 1-3h, and obtaining recycled water with an arsenic content of ≤0.2mg / L and a fluorine content of ≤5mg / L after solid-liquid separation.

[0012] As a further optimization scheme of the present invention, in step S3:

[0013] The waste acid reacts with the tailings as follows:

[0014] Fe2SiO4+2H2SO4→2FeSO4+H4SiO4

[0015] H4SiO4+6HF→H2SiF6+4H2O.

[0016] As a further optimization scheme of the present invention, in step S4:

[0017] Waste acid arsenic removal reaction:

[0018] Neutralization reaction

[0019] Ca(OH)2+H2SO4=CaSO4↓+2H2O

[0020] Ca(OH)2+H2SO3=CaSO3↓+2H2O

[0021] Main arsenic removal reactions

[0022] 3Ca(OH)2+2AsO4 3一 =Ca3(AsO4)2↓+6OH -

[0023] 2Fe 2+ +1 / 2O2+2H+=2F e3+ +H2O

[0024] 3Ca(OH)2+2Fe 3+ =2Fe(OH)3↓+3Ca 2+

[0025] AsO3 3一 +Fe(OH)3=FeAsO3↓+3OH 一

[0026] AsO4 3一 +Fe(OH)3=FeAsO4↓+3OH 一

[0027] Defluorination reaction:

[0028] Ca(OH)2+H2SiF6→CaSiF6↓+2H2O.

[0029] As a further optimization scheme of the present invention, the tailings are copper tailings with a particle size of ≥325 mesh.

[0030] As a further optimization scheme of the present invention, the mass ratio of tailings to water is 2-5 (g): 100-120 (ml).

[0031] As a further optimization scheme of the present invention, the calcium hydroxide adopts a particle size of ≥200 mesh.

[0032] As a further optimization scheme of the present invention, the mass ratio of calcium hydroxide to water is 20-45 (g): 100-130 (ml).

[0033] As a further optimization scheme of the present invention, the mass ratio of the slurry to the waste acid is 1:(3-5).

[0034] The beneficial effects of the present invention are as follows: the present invention fully utilizes the industrial waste of copper smelting tailings to convert the ferrous silicate therein into a processing raw material for a waste acid treatment agent; the present invention can efficiently remove arsenic and fluorine in the waste acid; by optimizing the treatment process and parameters, the deep removal of arsenic and fluorine in the waste acid can be achieved, and the relevant national emission standards can be met, which not only helps to reduce environmental pollution, but also can improve the resource utilization rate of the waste acid;

[0035] The present invention has significant environmental and economic advantages. By converting tailings into raw materials for waste acid treatment agents, the resource utilization of industrial waste is achieved, and waste discharge is reduced. At the same time, the method has low treatment cost, simple operation, and is easy to promote and apply. DETAILED DESCRIPTION

[0036] The present application is described in further detail below. It is necessary to point out that the following specific implementation methods are only used to further illustrate the present application and cannot be understood as limiting the scope of protection of the present application. Technicians in this field can make some non-essential improvements and adjustments to the present application based on the above application content.

[0037] Material

[0038] Unless otherwise specified, the methods used in the present invention are conventional methods known to those skilled in the art, and the reagents and other materials used are commercially available products unless otherwise specified.

[0039] (1) In the present invention

[0040] The waste acid in the present invention is the liquid of acidic wastewater containing high concentration of sulfuric acid and other impurities produced in the copper smelting process of a certain enterprise after being treated by the sulfidation process. The specific elements are shown in the following table:

[0041] element <![CDATA[H2S04]]> As F Concentration / mg / L 15000-50000 5-30 500-2000

[0042] (2) In the present invention

[0043] The waste acid reacts with the tailings as follows:

[0044] Fe2SiO4+2H2SO4→2FeSO4+H4SiO4

[0045] H4SiO4+6HF→H2SiF6+4H2O.

[0046] Waste acid arsenic removal reaction:

[0047] 3Ca(OH)2+2AsO4 3一 =Ca3(AsO4)2↓+6OH -

[0048] 2Fe 2+ +1 / 2O2+2H+=2F e3+ +H2O

[0049] 3Ca(OH)2+2Fe 3+ =2Fe(OH)3↓+3Ca 2+

[0050] AsO3 3一 +Fe(OH)3=FeAsO3↓+3OH 一

[0051] AsO4 3一 +Fe(OH)3=FeAsO4↓+3OH 一

[0052] Defluorination reaction:

[0053] Ca(OH)2+H2SiF6→CaSiF6↓+2H2O.

[0054] (3) In the present invention

[0055] The tailings are copper tailings with a particle size of ≥325 mesh;

[0056] The particle size of calcium hydroxide used shall be ≥200 mesh.

[0057] Example 1

[0058] The smelting slag produced by the smelting and blowing processes in the copper smelting process is processed through slow cooling, crushing, copper flotation and magnetic iron separation to obtain tailings;

[0059] Put the copper tailings and water into a stirring chamber, stir at 80r / min for 2h at 46℃ to obtain a slurry, and store it at a constant temperature of 42℃ for later use (the mass ratio of tailings to water is 2(g):100(ml));

[0060] The slurry and waste acid were placed in a stirring chamber, stirred at 20 r / min for 15 min, and then stirred at 20 r / min for 20 min after an interval of 30 min to obtain a prefabricated material (the mass ratio of the slurry to the waste acid was 1:3);

[0061] Calcium hydroxide + explosive oxygen is added to the prefabricated material to neutralize to pH = 8-8.5, and stirred at 120 r / min for 1-3 hours to obtain recycled water with an arsenic content of ≤ 0.5 mg / L and a fluorine content of ≤ 5 mg / L.

[0062] Example 2

[0063] The smelting slag produced by the smelting and blowing processes in the copper smelting process is processed through slow cooling, crushing, copper flotation and magnetic iron separation to obtain tailings;

[0064] Put the copper tailings and water into a stirring chamber, stir at 45°C and 60r / min for 1h to obtain a slurry, and store it at a constant temperature of 42°C for later use (the mass ratio of tailings to water is 3 (g): 110 (ml));

[0065] The slurry and waste acid were placed in a stirring chamber, stirred at 25 r / min for 15 min, and then stirred at 25 r / min for 15 min after an interval of 30 min to obtain a prefabricated material (the mass ratio of the slurry to the waste acid was 1:4);

[0066] Calcium hydroxide + explosive oxygen is added to the prefabricated material to neutralize to pH = 8-8.5, and stirred at 120 r / min for 1-3 hours to obtain recycled water with an arsenic content of ≤ 0.5 mg / L and a fluorine content of ≤ 5 mg / L.

[0067] Example 3

[0068] The smelting slag produced by the smelting and blowing processes in the copper smelting process is processed through slow cooling, crushing, copper flotation and magnetic iron separation to obtain tailings;

[0069] Put the copper tailings and water into a stirring chamber, stir at 50°C and 100r / min for 3h to obtain a slurry, and store it at a constant temperature of 42°C for later use (the mass ratio of tailings to water is 5 (g): 120 (ml));

[0070] The slurry and waste acid are placed in a stirring chamber, stirred at 30 r / min for 20 min, and then stirred at 30 r / min for 20 min after an interval of 30 min to obtain a prefabricated material (the mass ratio of the slurry to the waste acid is 1:5);

[0071] Quicklime powder and water were added to the prefabricated material, and stirred at 150 r / min for 3 h to obtain recycled water with an arsenic content of ≤0.5 mg / L and a fluorine content of ≤5 mg / L.

[0072] Performance Testing

[0073] The arsenic and fluorine in the recycled water obtained in Examples 1-3 were tested for elements. The test results are shown in the following table

[0074] project Arsenic content mg / L Fluoride content mg / L Example 1 0.25 4.8 Example 2 0.27 3.8 Example 3 0.28 3.1

[0075] As can be seen from the above table, the use of the methods of Examples 1-3 to remove arsenic and fluorine in waste acid can make the arsenic and fluorine in the waste acid meet the national emission standard of GB25467-2010. The effect of removing arsenic and fluorine in waste acid is good, reaching the reuse standard, and the treatment cost is greatly reduced, which effectively solves the problem of low removal efficiency in traditional treatment methods. This method converts the copper smelting tailings, an industrial waste, into a raw material for preparing a waste acid treatment agent, realizing the resource utilization of waste, which not only reduces the storage and disposal costs of the tailings, but also reduces the cost of waste acid treatment, and has good economic and environmental benefits.

[0076] The above-mentioned embodiments only express several implementation methods of the present invention, and the description thereof is relatively specific and detailed, but it cannot be understood as limiting the scope of the present invention. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention.

Claims

1. A method for synergistically treating fluorine-containing waste acid by using copper smelting tailings and calcium hydroxide, characterized in that: The following steps are involved: Step S1, taking the smelting slag produced by the smelting and blowing processes in the copper smelting process, and subjecting it to slow cooling, crushing, copper flotation, and magnetic iron separation processes to obtain tailings; Step S2, putting the tailings and water into a stirring bin, stirring at 45-50°C and 60-100 r / min for 1-3 hours to obtain a slurry, and storing it at a constant temperature of 42°C for later use; Step S3, placing the slurry and the waste acid into a stirring bin, stirring at 10-30 r / min for 10-20 min, and stirring at 10-30 r / min for 10-20 min after an interval of 30 min to obtain a prefabricated material; Step S4, adding calcium hydroxide + explosive oxygen to the prefabricated material, neutralizing to pH = 8-8.5, stirring at 120-150r / min for 1-3h, and obtaining recycled water with an arsenic content of ≤0.5mg / L and a fluorine content of ≤5mg / L after solid-liquid separation.

2. The method for synergistically treating fluorine-containing waste acid by using copper smelting tailings and calcium hydroxide according to claim 1, characterized in that: In step S3: The waste acid reacts with the tailings as follows: Fe2SiO4+2H2SO4→2FeSO4+H4SiO4 H4SiO4+6HF→H2SiF6+4H2O.

3. The method for synergistically treating fluorine-containing waste acid by using copper smelting tailings and calcium hydroxide according to claim 1, characterized in that: In step S4: Waste acid arsenic removal reaction: Neutralization reaction Ca(OH)2+H2SO4=CaSO4↓+2H2O Ca(OH)2+H2SO3=CaSO3↓+2H2O Main arsenic removal reactions 3Ca(OH)2+2AsO4 3一 =Ca3(AsO4)2↓+6OH - <h2 style=";text-align:left;direction:ltr">2Fe<h2 style=";text-align:left;direction:ltr"> 2+ <h2 style=";text-align:left;direction:ltr"> +1 / 2O2+2H+=2F<h2 style=";text-align:left;direction:ltr"> e3+ <h2 style=";text-align:left;direction:ltr"> +H2O 3Ca(OH)2+2Fe 3+ =2Fe(OH)3↓+3Ca 2+ <h2 style=";text-align:left;direction:ltr">AsO3<h2 style=";text-align:left;direction:ltr"> 3一 <h2 style=";text-align:left;direction:ltr"> +Fe(OH)3 = FeAsO3↓+3OH<h2 style=";text-align:left;direction:ltr"> 一 AsO4 3一 +Fe(OH)3=FeAsO4↓+3OH 一 Defluorination reaction: Ca(OH)2+H2SiF6→CaSiF6↓+2H2O.

4. The method for synergistically treating fluorine-containing waste acid by using copper smelting tailings and calcium hydroxide according to claim 1, characterized in that: The tailings are copper tailings with a particle size of ≥325 meshes.

5. The method for synergistically treating fluorine-containing waste acid by using copper smelting tailings and calcium hydroxide according to claim 1, characterized in that: The mass ratio of tailings to water is 2-5 (g): 100-120 (ml).

6. The method of claim 1, wherein the method comprises: The calcium hydroxide has a particle size of ≥200 meshes.

7. The method for synergistically treating fluorine-containing waste acid by using copper smelting tailings and calcium hydroxide according to claim 1, characterized in that: The mass ratio of calcium hydroxide to water is 20-45 (g): 100-130 (ml).

8. The method for synergistically treating fluorine-containing waste acid by using copper smelting tailings and calcium hydroxide according to claim 1, characterized in that: The mass ratio of the slurry to the waste acid is 1:(3-5).