CN116199320A - Optimized seed crystal for high-acid protein-containing arsenic-containing wastewater and method for stabilizing arsenic by optimized seed crystal - Google Patents

Abstract

An optimized seed crystal for high-acid protein-containing arsenic-containing wastewater and a method for stabilizing solid arsenic thereof belong to the technical field related to environmental protection water pollution treatment. Adding a pH regulator into the high-acid protein-containing arsenic-containing wastewater, regulating the pH value to be 1.5-2.5, carrying out solid-liquid separation, heating and stirring the primary solution, and carrying out solid-liquid separation again to obtain the crystal form scorodite; mixing crystal form scorodite and neutralizer to obtain slurry; and (3) reacting the slurry with high-acid protein-containing arsenic-containing wastewater, performing solid-liquid separation, and pickling, drying and grinding the obtained arsenic slag to obtain the optimized seed crystal. Mixing the optimized seed crystal and the neutralizer, adding the high-acid protein-containing arsenic-containing wastewater seed, and carrying out an arsenic removal reaction to obtain stable arsenic-fixing slag, wherein the arsenic removal rate is up to more than 99.99%. The method has simple process, reduces the arsenic slag quantity to 1/3-1/2 of the prior art, and can realize the recycling of resources.

Description

A kind of high-acid protein-containing arsenic-containing wastewater optimized seed crystal and its method for stabilizing arsenic

technical field

The invention belongs to the related technical field of environmental protection and water pollution control, and relates to a method for purifying waste water produced by high-arsenic refractory gold ore in a biometallurgical process, in particular to an optimized crystal seed of high-acid, protein-containing and arsenic-containing waste water and its stability method of arsenic fixation.

Background technique

Arsenic-bearing gold ore has become the most studied type of ore because of its largest reserves and highest recovery economic value. As a class I pollutant, arsenic widely exists in industrial wastewater, causing great pollution to water resources and soil. The biometallurgical process of high-arsenic refractory gold ores can oxidize the arsenic in the ore to pentavalent arsenic with low toxicity, so the biooxidation method has become a method with broad application prospects. The high-arsenic refractory gold ore will produce a large amount of high-acid protein-containing arsenic-containing wastewater in the biometallurgical process. In addition to the low-toxic pentavalent arsenic, the arsenic in the wastewater still contains a small amount of highly toxic trivalent arsenic and protein-bound arsenic. , if the direct discharge is not dealt with, it will bring serious harm to the environment and human health. Therefore, high-acid, protein-containing, and arsenic-containing wastewater must be treated to meet the standard before it can be discharged.

At present, there are many methods for the treatment of arsenic-containing wastewater, including chemical precipitation, flocculation, extraction, adsorption, and microbial methods, but chemical precipitation is the most widely used and the best effect in engineering practice. Sulfurization and lime neutralization are the most commonly used chemical precipitation methods. The vulcanization method has fast reaction speed, large processing capacity, and simple process, but the change of pH value will cause arsenic to dissolve again into the solution, and will generate toxic gas H ₂ S, which will pollute the atmosphere. At the same time, there are high cost of chemical treatment and large amount of residual sulfur in the effluent. Shortcomings. The lime neutralization method is currently the most widely used method for arsenic removal in industry because of its simple process and easy implementation, obvious cost advantages, and stable wastewater discharge standards.

In addition, in view of the unique water quality of high-acid protein-containing arsenic-containing wastewater (high acid-containing protein), lime neutralization method has also become a method for biometallurgical enterprises to treat high-acid protein-containing arsenic-containing wastewater. Although this method can remove most of the arsenic in high-acid protein-containing arsenic-containing wastewater, the arsenic content in the backwater is still higher than 0.5mg/L. If things go on like this, the gradual accumulation of arsenic will eventually have an adverse effect on the growth of bacteria; at the same time The main phases of the arsenic slag produced by the lime neutralization method are amorphous iron arsenate and calcium arsenate with high solubility, and the amount of slag is very large. The current disposal method for arsenic slag is to transport it to the tailings pond for storage. It is very easy to cause secondary pollution, and there is a great environmental hidden danger.

The patent with the publication number CN111170510A invented a method for treating arsenic-containing wastewater and solidifying arsenic. Although this invention makes the precipitation rate of arsenic in the wastewater reach 99.78%, all the precipitated arsenic is solidified in the form of scorodite, but the process Very cumbersome and difficult to realize industrial application.

Therefore, it is a technical problem to be solved urgently in this field to develop a method with simple process, high arsenic removal efficiency, small amount of arsenic slag, good effect of arsenic fixation, and resource recycling.

Contents of the invention

The purpose of the present invention is to overcome the problems existing in the prior art, and to provide an optimized seed crystal for high-acid, protein-containing, and arsenic-containing wastewater and a method for stably fixing arsenic. /3～1/2, the arsenic removal rate is as high as 99.99%, which can realize resource recycling.

The technical scheme that the present invention solves technical problem adopts is:

An optimized seed crystal of high-acid protein-containing arsenic-containing wastewater of the present invention is prepared by the following steps:

S1: Add a pH adjuster to the high-acid protein-containing arsenic-containing wastewater to adjust the pH value of the high-acid protein-containing arsenic-containing wastewater to 1.5-2.5 to obtain a primary slag mixed solution; solid-liquid separation to obtain a slag phase and a primary solution;

The primary solution is heated and stirred for 100-150 minutes, solid-liquid separation is performed again, and the obtained solid product is acid-washed and dried to obtain scorodite in crystal form;

S2: mixing scorodite in crystal form with a neutralizing agent to obtain a slurry;

reacting the slurry with high-acid, protein-containing, and arsenic-containing wastewater, and separating solid and liquid to obtain filtrate and arsenic slag;

S3: Pickling, drying, and grinding the arsenic slag to obtain optimized seed crystals of high-acid, protein-containing, and arsenic-containing wastewater.

In the above technical solution, the high-acid protein-containing arsenic-containing wastewater refers to arsenic content higher than 3g/L, iron content higher than 18g/L, sulfate radical content 60-120g/L, pH value ≤ 1, bacteria content 10 ³ to 10 ¹² cells/mL, and the protein content accounts for 60% to 70% of the bacterial content.

In the above technical solution, the pH regulator in the step S1 is one or both of calcium oxide and calcium hydroxide mixed with water to form a slurry with a mass fraction of 5% to 15%. The effect of adding the pH regulator is to adjust the pH value while reducing the ratio of iron to arsenic and the content of sulfate in the solution.

In the S1, the slag phase is a mixture of calcium sulfate, iron hydroxide, amorphous calcium arsenate and iron arsenate;

In said S1, the heating temperature is 90°C to 98°C;

In the above S1, the stirring speed is 800-1000 rpm, and the high-speed stirring is for forming scorodite crystal.

In the above technical scheme, in the step S2, the neutralizing agent is calcium oxide and magnesium oxide, or calcium hydroxide and magnesium hydroxide, and the compound of calcium:magnesium in mass ratio is formulated as 1:(10～3) Form an emulsion with a mass concentration of 5% to 30%.

In said S2, the addition amount of crystalline scorodite is 0.0001%-0.05% of the mass concentration of arsenic in high-acid protein-containing arsenic-containing wastewater.

In the S2, the addition ratio of crystal scorodite and neutralizing agent is controlled according to the pH value of the slurry, preferably the pH value is 3.5-4.5;

In S2, the reaction between the slurry and the high-acid, protein-containing, and arsenic-containing wastewater is as follows: the reaction is carried out at a stirring speed of 600-800 rpm and a pH of 3.5-4.5 for 15-40 minutes;

The arsenic content in the filtrate is lower than 0.5 mg/L, the iron content is lower than 50 mg/L, the sulfate content is 30-60 g/L, and the pH value is 3.5-5; the mass percentage of arsenic in the arsenic slag is 25-30% 1. The mass percentage content of iron is 15-25%, and the mass percentage content of sulfur is 4-8%.

In the above technical solution, in said S3, the particle size of the optimized seed crystal after mechanical grinding > 400 mesh accounts for more than 80%;

The optimized seed crystal is a mixture of ferric hydroxide, crystalline ferric arsenate (crystal form scorodite), magnesium arsenate and denatured protein precipitate.

A method for stabilizing arsenic in high-acid protein-containing arsenic-containing wastewater of the present invention by optimizing seed crystals, comprising the following steps:

Mix the optimized seed crystals of high-acid protein-containing arsenic-containing wastewater prepared above with a neutralizer, add high-acid protein-containing arsenic-containing wastewater seeds, and perform arsenic removal reaction to obtain a stable arsenic-fixed slag with arsenic removal rate as high as 99.99%.

In the technical scheme of the above-mentioned high-acid protein-containing arsenic-containing wastewater optimization seed crystal stable arsenic fixation method, the neutralizing agent is calcium oxide and magnesium oxide, or calcium hydroxide and magnesium hydroxide according to the compound of calcium: the quality of the compound of magnesium The ratio is 1:(10-3) to prepare an emulsion with a mass concentration of 5%-30%. Calcium oxide and magnesium oxide, or calcium hydroxide and magnesium hydroxide can adjust the pH value of high-acid, protein-containing, and arsenic-containing wastewater, and calcium oxide and magnesium oxide, or calcium hydroxide and magnesium hydroxide can react with acid to release heat. Improving the reaction rate, magnesium oxide can not only realize the selective separation of arsenic and sulfur in high-acid protein-containing arsenic-containing wastewater, reduce the amount of arsenic slag, but also improve the stability of arsenic slag. In the above-mentioned reaction process, too low concentration of the emulsion (less than 5%) will cause the amount of addition to increase, reduce the reaction efficiency, and increase the cost of water treatment after purification; if the concentration of the emulsion is too high (higher than 30%), it will As a result, the pH value of the reaction cannot be effectively controlled, and the generated calcium sulfate is easy to wrap the medicament, resulting in waste of the medicament.

The optimal seed crystal addition amount of the high-acid protein-containing arsenic-containing wastewater is 0.0005% to 0.1% of the mass concentration of arsenic in the high-acid protein-containing arsenic-containing wastewater.

The addition amount of the optimized seed crystal and neutralizer of the high-acid protein-containing arsenic-containing wastewater is controlled by the pH value of the solution, which is 3.5-5. In the above reaction process, it is very important to control the pH value to provide a reaction environment for the formation of crystalline scorodite with a stable structure.

The arsenic removal reaction condition is that the stirring speed is 600-800 rpm, the pH is 3.5-5, and the reaction is carried out for 40-60 minutes;

The mass percentage of arsenic in the arsenic-fixed slag is 5.5-7.5%, the mass percentage of iron is 25-32%, and the mass percentage of sulfur is 7.5-10%. The content is less than 1.2mg/L, meeting the relevant requirements of GB18598-2019.

The present invention provides a method for stabilizing arsenic in high-acid, protein-containing and arsenic-containing wastewater with optimized seed crystals. Compared with the prior art, the present invention has the beneficial effects of:

(1) High-acid protein-containing arsenic-containing wastewater has fast and complete arsenic removal, and stable arsenic fixation, so that the arsenic content in acidic wastewater with a molar ratio of iron (III) and arsenic (V) of 8 or more is lower than 0.5 mg/L ( The arsenic removal rate is above 99.98%), the iron content is less than 50mg/L (the iron removal rate is above 99.72%), the arsenic content in the toxic elution result of the arsenic-fixed slag is lower than 1.2mg/L, and the arsenic-fixed slag meets the requirements of hazardous waste landfill Relevant requirements of GB18598-2019.

(2) The present invention utilizes arsenic, iron, and protein in high-acid, protein-containing, and arsenic-containing wastewater to synthesize scorodite crystals and optimize seed crystals to produce high crystallinity and good arsenic-fixing effect for the subsequent neutralization and arsenic-removal stable arsenic fixation process The arsenic slag laid the foundation.

(3) The present invention provides a set of simple treatment process with simple equipment, easy operation, mild conditions, low cost, small amount of slag, easy separation of solid and liquid, stable properties of arsenic-fixed slag, selective precipitation of arsenic and sulfur, and high arsenic removal efficiency High, small amount of arsenic slag, good arsenic fixation effect, avoiding secondary pollution.

Description of drawings

Fig. 1 is the XRD of the arsenic-fixed slag obtained in Example 1 of the present invention.

Fig. 2 is the XRD of the arsenic-fixed slag obtained in the comparative example of Example 1 of the present invention.

Fig. 3 is a schematic process flow diagram of the method for stabilizing arsenic in high-acid protein-containing arsenic-containing wastewater of the present invention with optimized seed crystals.

Detailed ways

The specific implementation manner of the present invention will be further described in detail below in conjunction with specific examples. It should be noted that the following examples are used to illustrate the present invention, but not to limit the protection scope of the present invention.

Embodiment one

Take 400mL of high-acid, protein-containing, and arsenic-containing waste water from a biological oxidation smelter and place it in a beaker, wherein the arsenic concentration is 6280mg/L, the iron concentration is 22.3g/L, the sulfate radical is 112.3g/L, and the pH value is 0.9. The number of bacteria is 1000/mL, and the protein accounts for 60% of the bacteria. See Figure 3 for a schematic diagram of the process flow of the method for optimizing the stable arsenic fixation method of the high-acid protein-containing arsenic-containing wastewater, which specifically includes the following steps:

(1) Add calcium oxide slurry with a mass concentration of 5% to the high-acid, protein-containing, and arsenic-containing wastewater, adjust the pH value of the solution to 1.5, filter to remove the slag phase, and heat the remaining solution to 90°C, react at 800rpm for 120min, and then filter , the filtered solid product can be pickled and dried to obtain scorodite in crystal form;

(2) Get the crystal form scorodite obtained in step (1) by 0.05% of the arsenic mass concentration in the high-acid protein-containing arsenic-containing wastewater, and adjust the crystal form scorodite with calcium oxide+magnesia (1+10) A concentration of 5% is added to the high-acid, protein-containing, and arsenic-containing wastewater to adjust the pH of the solution to 4.5, react at 600 rpm for 40 minutes, and then filter to obtain the filtrate and arsenic slag. After testing, the arsenic content in the filtrate is 0.41 mg/L ( The arsenic removal rate is 99.993%), the iron content is 43mg/L (the iron removal rate is 99.807%), the sulfate content is 58.9g/L, the mass percentage of arsenic in the arsenic slag is 25%, and the mass percentage of iron is 25%. The mass percent content of sulfur is 4%. Among them, arsenic exists in the form of arsenate, the iron phase contains ferric hydroxide, sulfur exists in the form of sulfate, and there will be some crystal water, calcium, magnesium, etc.

(3) pickling the arsenic slag obtained in step (2), drying and mechanically grinding it as an optimized seed crystal for high-acid protein-containing arsenic-containing wastewater, with a particle size of +400 mesh, accounting for 80%;

(4) According to 0.0005% of the mass concentration of arsenic in high-acid, protein-containing, arsenic-containing wastewater, the optimized seed crystal of high-acid, protein-containing, and arsenic-containing wastewater obtained in step (3) is mixed with calcium oxide+magnesium oxide (1+10) to form a concentration of 5% slurry is used as a new arsenic removal agent for high-acid, protein-containing, and arsenic-containing wastewater. Adjust the pH of the solution to 5, and react at 600 rpm for 60 minutes to obtain a stable arsenic-fixed slag. The arsenic removal rate is as high as 99.99%. The resulting arsenic slag As shown in Figure 1, the XRD of the arsenic-fixed slag contains 7.5% by mass of arsenic, 32% by mass of iron, and 7.5% by mass of sulfur. It is 0.12mg/L, meeting the relevant requirements of GB18598-2019.

Comparative example one

In contrast, in the treatment process of the high-acid protein-containing arsenic-containing wastewater in Example 1, no optimized seed crystals were added to the high-acid protein-containing arsenic-containing wastewater, and step (4) was directly carried out, and the conditions were consistent with Example 1. The XRD of the obtained arsenic slag is shown in Figure 2, the crystallinity is poor, the mass percentage of arsenic in the arsenic slag is 5.13%, the mass percentage of iron is 29.26%, and the mass percentage of sulfur is 8.51%. The arsenic-containing slag was subjected to a toxicity dissolution test according to HJ766. After testing, the arsenic content was 1.12mg/L. Although the stability of the arsenic slag met the relevant requirements of GB18598-2019, it was close to the limit of 1.2mg/L.

Embodiment two

Take 400mL of high-acid protein-containing arsenic-containing wastewater from a biological oxidation smelter and put it in a beaker, in which the concentration of arsenic is 4160mg/L, the concentration of iron is 18.3g/L, the pH value is 1.0, and the content of sulfate radical is 62.3g/L , the number of bacteria is 10 ¹² /mL, and the protein accounts for 70% of the bacteria.

(1) Add calcium hydroxide slurry with a mass concentration of 15% to the high-acid, protein-containing, and arsenic-containing wastewater, adjust the pH value of the solution to 2.5, filter and remove the slag phase, and heat the remaining solution to 98°C and react for 120 minutes at 1000rpm Filtration, pickling and drying the filtered solid product to obtain scorodite in crystal form;

(2) Get the crystal form scorodite obtained in step (1) according to 0.0001% of the mass concentration of arsenic in the high-acid protein-containing arsenic-containing wastewater, adjust the crystal form scorodite and calcium oxide+magnesium oxide (1+3) into the quality Concentration is the slurry of 30%, joins in the high-acid protein-containing arsenic-containing wastewater, adjusts the pH of the solution to be 3.5, reacts at 800 rpm for 15 minutes and then filters to obtain the filtrate and arsenic slag. After testing, the arsenic content in the filtrate is 0.34 mg/L ( Arsenic rate 99.992%), iron content is 35mg/L (removal rate 99.81%), sulfate radical content is 30.1g/L, the mass percentage content of arsenic in the arsenic slag is 30%, the mass percentage content of iron is 15%, The mass percent content of sulfur is 8%;

(3) pickling the arsenic slag obtained in step (2), drying and mechanically grinding it as an optimized seed crystal for high-acid protein-containing arsenic-containing wastewater, with a particle size of +400 mesh, accounting for 90%;

(4) According to 0.1% of the mass concentration of arsenic in high-acid, protein-containing, arsenic-containing wastewater, the optimized seed crystal of high-acid, protein-containing, and arsenic-containing wastewater obtained in step (3) is mixed with calcium oxide+magnesium oxide (1+3) to adjust the quality The slurry with a concentration of 30% is used as a new arsenic removal agent for high-acid, protein-containing, and arsenic-containing wastewater. The pH of the solution is adjusted to 4.5, and a stable arsenic-fixed slag is obtained after reacting at 600rpm for 40 minutes. The arsenic removal rate is as high as 99.99%. The mass percentage of arsenic in the slag is 5.5%, the mass percentage of iron is 25%, and the mass percentage of sulfur is 10%. .

Embodiment three

Take 400mL of high-acid protein-containing arsenic-containing wastewater from a biological oxidation smelter and put it in a beaker, in which the concentration of arsenic is 3100mg/L, the concentration of iron is 20.3g/L, the pH value is 0.85, and the sulfate content is 78.1g/L , the number of bacteria is 10 ⁵ /mL, and the protein accounts for 65% of the bacteria.

(1) Add calcium hydroxide slurry with a mass concentration of 10% to high-acid, protein-containing, and arsenic-containing wastewater, adjust the pH value of the solution to 2, filter and remove the slag phase, and then heat the remaining solution to 95°C and react at 900rpm for 120min Filtration, pickling and drying the filtered solid product to obtain scorodite in crystal form;

(2) Get the crystal form scorodite obtained in step (1) according to 0.001% of the mass concentration of arsenic in the high-acid protein-containing arsenic-containing wastewater, adjust the crystal form scorodite and calcium oxide+magnesia (1+5) into the quality Concentration is the slurry of 10%, joins in the high-acid protein-containing arsenic-containing wastewater, adjusts the pH of the solution to be 4.0, reacts at 700rpm for 25min and then filters to obtain the filtrate and arsenic slag. After testing, the arsenic content in the filtrate is 0.11mg/L ( Arsenic rate 99.996%), iron content is 23mg/L (removal rate 99.886%), sulfate content is 41g/L, the mass percentage content of arsenic in arsenic slag is 26.9%, the mass percentage content of iron 20%, sulfur The mass percentage content of 5.9%;

(3) Pickling the arsenic slag obtained in step (2), drying and mechanically grinding it as an optimized seed crystal for high-acid protein-containing arsenic-containing wastewater, the particle size is +400 mesh, accounting for 85%;

(4) According to 0.005% of the arsenic mass concentration in the high-acid protein-containing arsenic-containing wastewater, the optimized seed crystal of the high-acid protein-containing arsenic-containing wastewater obtained in step (3) is adjusted to the mass concentration with calcium oxide+magnesium oxide (1+5) 10% slurry is used as a new arsenic removal agent for high-acid, protein-containing, and arsenic-containing wastewater. Adjust the pH of the solution to 3.5, and react at 700 rpm for 50 minutes to obtain a stable arsenic-fixed slag. The arsenic-fixed slag is as high as 99.99%. The mass percentage of arsenic in the medium is 6.1%, the mass percentage of iron is 27.4%, and the mass percentage of sulfur is 8.3%.

Embodiment four

Take 400mL of high-acid protein-containing arsenic-containing wastewater from a biological oxidation smelter and put it in a beaker, in which the concentration of arsenic is 5090mg/L, the concentration of iron is 30.7g/L, the pH value is 0.91, and the sulfate content is 90.1g/L , the number of bacteria was 10 ⁷ /mL, and the protein accounted for 63% of the bacteria.

(1) Add calcium hydroxide slurry with a mass concentration of 7.5% to the high-acid, protein-containing, and arsenic-containing wastewater, adjust the pH value of the solution to 1.8, filter and remove the slag phase, and heat the remaining solution to 93°C and react at 750rpm for 120min Filtration, pickling and drying the filtered solid product to obtain scorodite in crystal form;

(2) Get the crystal form scorodite obtained in step (1) according to 0.01% of the arsenic mass concentration in the high-acid protein-containing arsenic-containing wastewater, and adjust the crystal form scorodite and calcium oxide+magnesia (1+7) into the quality Concentration is the slurry of 15%, joins in the high-acid protein-containing arsenic-containing wastewater, adjusts the pH of the solution to be 3.75, reacts at 650 rpm for 20 minutes and then filters to obtain the filtrate and arsenic slag. After testing, the arsenic content in the filtrate is 0.44 mg/L ( Arsenic rate 99.991%), iron content 49.7mg/L (removal rate 99.83%), sulfate content 37.3g/L, mass percentage of arsenic in arsenic slag 28.6%, mass percentage of iron 18.1% , The mass percent content of sulfur is 5%;

(3) Pickling the arsenic slag obtained in step (2), drying and mechanically grinding it as an optimized seed crystal for high-acid protein-containing arsenic-containing wastewater, the particle size is +400 mesh, accounting for 87%;

(4) According to 0.05% of the mass concentration of arsenic in high-acid, protein-containing, arsenic-containing wastewater, the optimized seed crystal of high-acid, protein-containing, and arsenic-containing wastewater obtained in step (3) is mixed with calcium oxide+magnesium oxide (1+7) to adjust the quality The slurry with a concentration of 15% is used as a new arsenic removal agent for high-acid, protein-containing, and arsenic-containing wastewater. Adjust the pH of the solution to 4.0, and react at 650rpm for 45 minutes to obtain a stable arsenic-fixed slag. The arsenic removal rate is as high as 99.99%. The mass percentage of arsenic in the slag is 6.9%, the mass percentage of iron is 26.8%, and the mass percentage of sulfur is 7.9%. .

Embodiment five

Take 400mL of high-acid protein-containing arsenic-containing wastewater from a biological oxidation smelter and put it in a beaker, in which the arsenic concentration is 3210mg/L, the iron concentration is 21.7g/L, the pH value is 0.7, and the sulfate content is 107.5g/L , the number of bacteria was 10 ⁹ /mL, and the protein accounted for 68% of the bacteria.

(1) Add calcium hydroxide slurry with a mass concentration of 12.5% to the high-acid, protein-containing, and arsenic-containing wastewater, adjust the pH value of the solution to 2.3, filter and remove the slag phase, and then heat the remaining solution to 96.5°C and react for 120 minutes at 950 rpm Filtration, pickling and drying the filtered solid product to obtain scorodite in crystal form;

(2) Get the crystal form scorodite obtained in step (1) according to 0.03% of the mass concentration of arsenic in the high-acid protein-containing arsenic-containing wastewater, adjust the crystal form scorodite and calcium oxide+magnesia (1+9) into the quality Concentration is the slurry of 20%, joins in high acid waste water containing protein and arsenic, adjusts the pH of the solution to be 4.25, reacts at 750rpm for 30min and then filters to obtain the filtrate and arsenic slag. After testing, the arsenic content in the filtrate is 0.17mg/L ( Arsenic rate 99.994%), iron content is 47mg/L (removal rate 99.78%), sulfate radical content is 41.2g/L, the mass percentage content of arsenic in the arsenic slag is 26%, the mass percentage content of iron is 22.5%, The mass percentage of sulfur is 7%;

(3) Pickling the arsenic slag obtained in step (2), drying and mechanically grinding it as an optimized seed crystal for high-acid protein-containing arsenic-containing wastewater, the particle size is +400 mesh, accounting for 83%;

(4) According to 0.01% of the mass concentration of arsenic in high-acid, protein-containing, arsenic-containing wastewater, the optimized seed crystal of high-acid, protein-containing, and arsenic-containing wastewater obtained in step (3) is mixed with calcium oxide+magnesium oxide (1+9) to adjust the quality The slurry with a concentration of 20% is used as a new arsenic removal agent for high-acid, protein-containing, and arsenic-containing wastewater. Adjust the pH of the solution to 4.7, and react at 750rpm for 55 minutes to obtain a stable arsenic-fixed slag. The arsenic removal rate is as high as 99.99%. The mass percentage of arsenic in the slag is 5.7%, the mass percentage of iron is 29.3%, and the mass percentage of sulfur is 9.1%. .

Comparative example two

Same as Example 1, the difference is that in step (1), the stirring rate used is 100rpm, then the optimized seed crystals obtained have large grains, and subsequent crystallization reactions are not easy to carry out in the process of stable arsenic fixation .

Comparative example three

The same as in Example 1, the difference is that in the neutralizer used, the concentration of the emulsion is 2%, which will lead to an increase in the addition amount, reduce the reaction efficiency, and increase the cost of water treatment after purification.

Comparative example four

With embodiment one, the difference is that, in the neutralizing agent that adopts, the concentration of emulsion is 50%, and then can not effectively control reaction pH value, and the calcium sulfate that generates easily wraps medicament, causes the waste of medicament.

Comparative example five

Same as Example 1, the difference is that after adding the neutralizing agent, when the pH value is lower than 3.5, the arsenic content in the filtrate obtained after the reaction is 1310 mg/L (the arsenic removal rate is 79.14%), which is much higher than that of industrial wastewater The emission of arsenic in water is 0.5mg/L.

Claims (10)

1. The optimized seed crystal for the high-acid protein-containing arsenic-containing wastewater is characterized by being prepared by the following steps:

s1: adding a pH regulator into the high-acid protein-containing arsenic-containing wastewater, and regulating the pH value of the high-acid protein-containing arsenic-containing wastewater to be 1.5-2.5 to obtain a primary slag mixed solution; solid-liquid separation is carried out to obtain a slag phase and a primary solution;

heating and stirring the primary solution, performing solid-liquid separation again, and pickling and drying the obtained solid product to obtain the crystal form scorodite;

s2: mixing crystal form scorodite and neutralizer to obtain slurry;

reacting the slurry with high-acid protein-containing arsenic-containing wastewater, and carrying out solid-liquid separation to obtain filtrate and arsenic slag;

s3: and (3) pickling, drying and grinding the arsenic slag to obtain the high-acid protein-containing arsenic-containing wastewater optimized seed crystal.

2. The optimized seed crystal for high-acid protein-containing arsenic-containing wastewater according to claim 1, wherein the high-acid protein-containing arsenic-containing wastewater is characterized in that the arsenic content is higher than 3g/L, the iron content is higher than 18g/L, the sulfate content is 60-120 g/L, pH value less than or equal to 1, and the bacterial content is 10 ³ ～10 ¹² The protein content accounts for 60 to 70 percent of the bacterial content per mL.

3. The optimized seed crystal for the high-acid protein-containing arsenic-containing wastewater according to claim 1, wherein in the step S1, one or two of calcium oxide and calcium hydroxide are mixed with water to prepare slurry with the mass fraction of 5-15%; the slag phase is a mixture of calcium sulfate, ferric hydroxide, amorphous calcium arsenate and ferric arsenate;

the heating temperature is 90-98 ℃; the stirring speed is 800-1000 rpm, and the stirring time is 100-150 min.

4. The optimized seed crystal for the high-acid protein-containing arsenic-containing wastewater according to claim 1, wherein in the step S2, the neutralizing agent is calcium oxide and magnesium oxide or a compound of calcium hydroxide and magnesium hydroxide in mass ratio of calcium: the magnesium compound is 1: (10-3) preparing an emulsion with the mass concentration of 5-30%;

the addition amount of the crystal form scorodite is 0.0001-0.05% of the arsenic mass concentration in the high-acid protein-containing arsenic-containing wastewater;

the adding ratio of the crystal form scorodite and the neutralizer is controlled according to the pH value of the slurry, and the pH value of the slurry is 3.5-4.5.

5. The optimized seed crystal for high acid protein arsenic wastewater according to claim 1, wherein in S2, the slurry and the high acid protein arsenic wastewater react as follows: reacting for 15-40 min at the stirring speed of 600-800 rpm and the pH value of 3.5-4.5.

6. The optimized seed crystal for the high-acid protein-containing arsenic-containing wastewater, according to claim 1, wherein the arsenic content in the filtrate is lower than 0.5mg/L, the iron content is lower than 50mg/L, the sulfate content is 30-60 g/L, and the pH value is 3.5-5; the arsenic slag contains 25-30% of arsenic, 15-25% of iron and 4-8% of sulfur.

7. The optimized seed crystal for high-acid protein-containing arsenic-containing wastewater according to claim 1, wherein in S3, the optimized seed crystal has a grain size of >400 mesh accounting for 80% or more after mechanical grinding; the optimized seed crystal is a mixture of ferric hydroxide, crystalline ferric arsenate, magnesium arsenate and denatured protein precipitate.

8. The method for optimizing seed crystal stabilization of arsenic-containing wastewater containing protein and arsenic with high acid according to any one of claims 1 to 7, comprising the following steps:

mixing the optimized seed crystal of the high-acid protein-containing arsenic-containing wastewater and the neutralizer, adding the seed crystal of the high-acid protein-containing arsenic-containing wastewater, and carrying out an arsenic removal reaction to obtain stable arsenic-fixing slag, wherein the arsenic removal rate is as high as more than 99.99%.

9. The method for optimizing seed crystal stabilization of arsenic-containing wastewater with high acid and protein according to claim 8, wherein the neutralizing agent is calcium oxide and magnesium oxide or calcium hydroxide and magnesium hydroxide according to calcium compound: the mass ratio of the magnesium compound is 1: (10-3) preparing an emulsion with the mass concentration of 5-30%;

the optimized seed crystal addition amount of the high-acid protein-containing arsenic-containing wastewater is 0.0005% -0.1% of the arsenic mass concentration in the high-acid protein-containing arsenic-containing wastewater;

the addition amount of the optimized seed crystal and the neutralizer of the high-acid protein-containing arsenic-containing wastewater is controlled by the pH value of the solution;

the dearsenifying reaction condition is that the stirring speed is 600-800 rpm, and the pH value is 3.5-5, and the reaction is carried out for 40-60 min.

10. The method for stabilizing solid arsenic by optimizing seed crystal for high acid protein-containing arsenic-containing wastewater according to claim 8, wherein the solid arsenic slag contains 5.5-7.5 mass percent of arsenic, 25-32 mass percent of iron and 7.5-10 mass percent of sulfur, and the solid arsenic slag toxic leaching result is less than 1.2mg/L and meets the related requirements of GB 18598-2019.

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