A method for controlling heavy metal pollution of tin polymetallic ore tailings

Abstract

The present application relates to a method for controlling heavy metal pollution of tin polymetallic ore tailings, which can effectively solve the problem of heavy metal pollution of tin polymetallic ore tailings. A stabilizer is provided, including a basic component A and a reinforcing component B; wherein the basic component A is polyaluminum ferric chloride 25%-45%, ferrous sulfate 15%, calcium hydroxide 20%-40%, calcium carbonate 20%-30%, and iron oxide 0.1%-3%; the reinforcing component B is sodium tripolyphosphate and / or sodium silicate, and is prepared into an aqueous solution for use. The polyaluminum ferric chloride, ferrous sulfate, calcium hydroxide, calcium carbonate, and iron oxide are uniformly mixed and activated to obtain the basic component A; the reinforcing component B is prepared into an aqueous solution with a concentration of 0.1-2.0% for use. Using the method of the present application, the heavy metal pollutants in the tin polymetallic ore tailings can be solidified and stabilized, the leaching of heavy metals in the tailings can be significantly reduced, and the diffusion of residual heavy metal pollutants in the tailings to soil, groundwater, and surface water can be prevented.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of tailings treatment, and more particularly to a method for controlling heavy metal pollution of tin polymetallic ore tailings. BACKGROUND

[0002] In addition to containing cassiterite (SnO2), tin polymetallic ore usually also contains jamesite (Pb4FeSb6S 14 ), sphalerite (ZnS), pyrite (FeS2), arsenopyrite (FeAsS) and other metal sulfide minerals, and a small amount of water-soluble heavy metal sulfates and sulfites generated by the oxidation of sulfide minerals. Due to the complexity of geological ore-forming conditions, various metal minerals are intergrown, and some metals enter the crystal lattice of other metal minerals in the form of isomorphism, while some metal minerals are finely disseminated in gangue (non-metallic minerals), making it difficult to separate and recover the minerals. After beneficiation, a variety of heavy metal minerals, such as a small amount of jamesite containing lead and antimony, sphalerite containing cadmium, pyrite containing arsenic and sulfur, and arsenopyrite, are inevitably left in the tailings. Therefore, tin polymetallic ore tailings usually contain water-soluble heavy metal substances and heavy metal sulfide minerals that are difficult to dissolve in water but can be oxidized.

[0003] Due to the presence of these elements such as cadmium, lead, arsenic, zinc and sulfur, the industrial utilization of tin polymetallic ore tailings is limited, and the tailings disposed by stacking in tailings ponds and dry piles in the natural environment will also be oxidized due to the combined action of water and oxygen, especially acid rain erosion, resulting in the oxidation of metal minerals to generate various water-soluble substances such as heavy metal sulfates. At the same time, the oxidation of metal sulfides such as pyrite (FeS2), arsenopyrite (FeAsS) and sphalerite in the tailings will also produce acidic substances, further causing the acidification of the microenvironment in the tailings and exacerbating the leaching of heavy metals. It can be seen that after the tin polymetallic ore tailings are soaked in water, the heavy metals such as arsenic and cadmium in the tailings are transferred to the water phase, and the concentration can exceed the limit value of the "Integrated Wastewater Discharge Standard" (GB8978-1996), which is usually classified as Class II solid waste, or even hazardous waste, causing serious heavy metal pollution to the ecological environment. For a long time, the mining of tin polymetallic ore has resulted in the generation of a large amount of tailings containing heavy metal pollutants, which has had a significant impact on the local ecological environment, especially the soil, groundwater and surface water resources. Therefore, controlling heavy metal pollution of tin polymetallic ore tailings and achieving harmless disposal of tin polymetallic tailings containing multiple heavy metal pollutants such as cadmium, lead, arsenic and zinc have become urgent and important ecological and social problems facing the tin polymetallic mining and beneficiation industry.

[0004] The invention patent with publication number CN115093168A grinds, sieves and dries tin tailings and cement respectively to obtain tin tailings powder and cement powder, uniformly mixes the tin tailings powder and the cement powder to obtain a mixture A, adds water to the mixture A and uniformly mixes to obtain slurry B, pours the slurry B into a mold and seals and stands at room temperature for 24-48 hours, and after demolding, cures at room temperature and humidity of 90-95% for more than 3 days to obtain an arsenic-containing solid. In this method, "cement accounts for 30-60 wt.% and the rest is tin tailings powder". The invention patent with publication number CN112479608B has a solidification stabilizing agent dosage of 3-10%. These tailings solidification and stabilization tailings treatment methods have a significantly large tailings volume increase, and more space is needed for disposal, wasting valuable land resources. SUMMARY

[0005] The technical problem to be solved by the present application is to provide a method for controlling heavy metal pollution of tin polymetallic mine tailings, solving the harmless disposal problem of tin polymetallic mine tailings containing heavy metal pollutants such as cadmium, lead, arsenic and zinc. The heavy metal pollutants in the tin polymetallic mine tailings are solidified and stabilized, the pollution hazards and hidden dangers of the tin polymetallic mine tailings are eliminated, and the high-pollution industry is transformed into a green and low-pollution industry.

[0006] To solve the technical problem, the present application adopts the following technical solution:

[0007] A method for controlling heavy metal pollution of tin polymetallic mine tailings, first provides a stabilizer, the stabilizer comprising: a base component A and a reinforcing component B;

[0008] The base component A comprises polyaluminum ferric chloride, ferrous sulfate, calcium hydroxide, calcium carbonate and iron oxide.

[0009] The polyaluminum ferric chloride is an industrial product, and the main components are aluminum oxide >= 26%. Iron oxide 3%-6%, basicity >= 65%, arsenic <= 0.0003%;

[0010] The calcium hydroxide, ferrous sulfate, calcium carbonate and iron oxide are all industrial products.

[0011] Preferably, the calcium hydroxide, ferrous sulfate, calcium carbonate and iron oxide are analytical pure products.

[0012] The base component A is: polyaluminum ferric chloride 25%-45%, ferrous sulfate 15%, calcium hydroxide 20%-40%, calcium carbonate 20%-30%, and iron oxide 0.1%-3%, based on a total mass of 100%.

[0013] Preferably, the base component A is: polyaluminum ferric chloride 35 kg, ferrous sulfate 15 kg, calcium hydroxide 35 kg, calcium carbonate 14 kg, and iron oxide 1 kg.

[0014] The preparation method of the base component A is that polyaluminum ferric chloride, ferrous sulfate, calcium hydroxide, calcium carbonate and iron oxide are uniformly mixed according to proportions, ground in a grinding device, and finely ground to ≦200 meshes for mechanical activation.

[0015] Preferably, the grinding device refers to a ball mill, a Raymond mill, etc.

[0016] The reinforcing component B refers to industrial-grade sodium tripolyphosphate and / or sodium silicate.

[0017] Preferably, the reinforcing component B refers to analytical pure sodium tripolyphosphate.

[0018] The tin polymetallic ore tailings contain at least one of heavy metals cadmium, lead, arsenic and zinc.

[0019] The application also provides a method for controlling heavy metal pollution of tin polymetallic ore tailings, comprising the following steps:

[0020] Step one: uniformly mixing the base component A with tin polymetallic ore tailings at a mass ratio of 0.5% to 3%;

[0021] Step two: adding a water solution of the reinforcing component B with a concentration of 0.1 to 2.0% to the tin polymetallic ore tailings uniformly mixed in step one to form a solidified and stabilized body with a water content of 15% to 25%;

[0022] Step three: stacking the solidified and stabilized body obtained in step two to form a solidified body of tin polymetallic ore tailings;

[0023] Step four: curing the solidified body to complete the solidification and stabilization of heavy metal pollution of tin polymetallic ore tailings.

[0024] Preferably, in step two, the concentration of the water solution is 0.2%, and the water content is 25%.

[0025] Preferably, the pH of the solidified and stabilized body obtained in step two is controlled to be 7.5 to 9 by controlling the amount of the base component A in step one.

[0026] Preferably, in step four, the curing time is 24 hours.

[0027] Advantages

[0028] Compared with the prior art, the application has the following main advantages:

[0029] The tin polymetallic ore tailings are usually 120 mesh to 200 mesh, and the heavy metals such as arsenic, cadmium, lead and zinc in the tailings have two phases in terms of solubility, one is the easily soluble substance containing one or more of the heavy metals such as arsenic, cadmium, lead and zinc, and the other is the hardly soluble substance containing heavy metal sulfide minerals such as arsenic, cadmium, lead and zinc; the latter heavy metal sulfide minerals containing arsenic, cadmium, lead or zinc are also easy to be oxidized to generate the easily soluble substance under the condition of water and oxygen, which are the main reasons leading to the heavy metal pollution of the tin polymetallic ore tailings to the environment. The present application controls the heavy metal pollution of the tailings from multiple dimensions. The polyaluminum ferric chloride, ferrous sulfate, calcium hydroxide, calcium carbonate and iron oxide used in the present application are compounded and mechanically ground to 200 mesh, and the physicochemical properties are changed. A large amount of data shows that the finer the particle size of the material is, the larger the specific surface area is, and the larger the surface free energy is. The stabilizer is less than 200 mesh, and the heavy metal pollutants are one or more of cadmium, lead, arsenic and zinc. When the content of arsenic in the tailings is less than or equal to 10000 mg / kg, the content of lead is less than or equal to 5000 mg / kg, and the content of zinc is less than or equal to 5000 mg / kg, the stabilizer can be better mixed with the tailings which are also fine and evenly distributed between various minerals. Under the action of the strengthening component and water, the stabilizer first undergoes hydrolysis reaction and immediately undergoes a series of chemical reactions with the heavy metals such as cadmium, arsenic and zinc. XRD test shows that Cd4Al2O6C l2 10H2O is generated with cadmium, Al2(AsO4)(OH)3·3H2O is generated with arsenic, and Zn5(OH)8Cl2·H2O is generated with zinc (see Figure 2 , Figure 3 , Figure 4 example); at the same time, complex agglomeration, polymerization, adsorption and bridging and other physicochemical mineralization effects are generated. Referring to the EDS detection results of the stabilized lead-zinc ore tailings, the heavy metals such as arsenic, copper and lead and the iron and aluminum hydrolysis colloid in the stabilizer generate polynuclear complexes and are fixed together (see Figure 5 example), which greatly reduces the toxicity and leaching rate of the heavy metals. The selection of sodium tripolyphosphate as a reinforcing agent and the synergistic effect with the basic component A make the heavy metal minerals generated in the solidification process more stable. The heavy metal pollutants in the toxicity leaching of the stabilized tin polymetallic ore tailings are far lower than the limit value of the “Integrated Wastewater Discharge Standard” (GB8978-1996). The tin polymetallic ore tailings are changed from Class II solid waste to Class I solid waste, and the concentration of the heavy metal pollutants in the leaching liquid is lower than the limit value of the Class III water standard of surface water, and the environmental pollution risk is very low. It can be seen that the heavy metal stabilizer for tin polymetallic ore tailings of the present application is a kind of heavy metal solidification and stabilization agent which has fast effect and good effect.

[0030] The calcium carbonate and iron oxide in the stabilizer for controlling heavy metal pollution of tin polymetallic ore tailings are difficult to dissolve in water, but can react with acid in an acidic aqueous solution, and the acid generated by oxidation of sulfide minerals in the tailings is immediately neutralized by the calcium carbonate and iron oxide, thereby preventing further oxidation and precipitation of various heavy metal minerals in the tailings. The stabilizer has strong resistance to acid rain and sulfide mineral acidification, and therefore the tin polymetallic ore tailings heavy metal stabilizer of the present application has the function of stabilizing the pH of the tailings solidified body, and the solidified and stabilized tailings has good weather resistance, can be stably and effectively reduced for a long time, and can effectively reduce the leaching of heavy metal pollutants in the tin polymetallic ore tailings.

[0031] The amount of the stabilizer is only 0.5% to 3% of the tin polymetallic ore tailings by mass, the amount is small, and the volume of the treated tailings is increased little; the heavy metal cadmium, lead, zinc and semimetal arsenic in the tailings can be simultaneously solidified and stabilized. BRIEF DESCRIPTION OF DRAWINGS

[0032] Figure 1 The figure is a process flow diagram of the tin polymetallic ore tailings heavy metal pollution control stabilizer and application process of the present application.

[0033] Figure 2 The figure is an XRD graph of the reaction of the stabilizer of the present application with cadmium (Cd).

[0034] Figure 3 The figure is an XRD graph of the reaction of the stabilizer of the present application with arsenic (As).

[0035] Figure 4 The figure is an XRD graph of the reaction of the stabilizer of the present application with zinc (Zn).

[0036] Figure 5 The figure is an EDS detection result of the solidified and stabilized lead-zinc ore tailings. DETAILED DESCRIPTION

[0037] The present application will be further described below in combination with the drawings and specific examples, so that those skilled in the art can better understand the present application and implement it, but the examples are not intended to limit the present application.

[0038] The stabilizing agent of the present application is composed of a basic component A and a reinforcing component B. The basic component A is prepared by mechanically activating the following components: polyaluminum ferric chloride, ferrous sulfate, calcium hydroxide, calcium carbonate, and iron oxide, and has a particle size of ≤200 mesh. The reinforcing component B is sodium tripolyphosphate, which is prepared into an aqueous solution. When the heavy metal pollutants are one or more of cadmium, lead, arsenic, and zinc, and the content of arsenic in the tailings is ≤10,000 mg / kg, the content of lead is ≤5,000 mg / kg, and the content of zinc is ≤5,000 mg / kg, the basic component A of the stabilizer is added to the tin polymetallic ore tailings and mixed evenly. The basic component A can be uniformly distributed between the tailings particles due to its fine particle size. After the addition of the aqueous solution of the reinforcing component B, the stabilizer hydrolysis generates polynuclear hydroxyl ions, chain colloids, etc. On the one hand, it reacts with the free heavy metal ions such as cadmium, arsenic, zinc, and lead in the tailings to generate a series of substances such as Cd4Al2O6Cl2·10H2O, Al2(AsO4)(OH)3·3H2O, and Zn5(OH)8Cl2·H2O (see Figure 2 , Figure 3 , Figure 4 Example), and on the other hand, it simultaneously undergoes a series of bridging, polymerization, adsorption, and other physicochemical reactions with water-soluble heavy metal substances, mineral particles, etc., preventing the oxidation of sulfides and the leaching of heavy metals in the tailings. The EDS detection results of a certain tin polymetallic ore tailings after stabilization show that the heavy metals such as arsenic, copper, and lead are hydrolyzed with the iron and aluminum colloids in the stabilizer to form polynuclear polymers, which are consolidated together. Reference is made to the EDS detection results of lead-zinc ore tailings after stabilization Figure 5 Example.

[0039] Control example (without adding stabilizer)

[0040] In order to better illustrate the effect of the present application on stabilizing heavy metal pollutants, a certain tin polymetallic ore tailings without stabilizer treatment was subjected to leaching toxicity leaching test to investigate the water leaching of heavy metal pollutants in the tailings. The content of arsenic in the certain tin polymetallic ore tailings was 8616 mg / kg, the content of lead was 3523 mg / kg, the content of zinc was 4760 mg / kg, and the content of cadmium was 237 mg / kg.

[0041] The method of this control example (without adding stabilizer) is to take a certain tin polymetallic ore tailings without stabilizer, and perform leaching toxicity test according to the standard requirements of “Solid Waste Leaching Toxicity Leaching Method Horizontal Oscillation Method” (HJ557-2010). The relevant results are shown in Table 1. As can be seen from Table 1, the content of arsenic and cadmium in the leaching solution of the tin polymetallic ore tailings without stabilizer is high, which exceeds the limit value of “Integrated Wastewater Discharge Standard” (GB8978-1996), and according to the judgment of the relevant national standards, the certain tin polymetallic ore tailings belongs to Class II industrial solid waste; the content of cadmium, arsenic, lead, and zinc in the leaching solution all exceeds the national surface water environmental quality standard, indicating that the tin polymetallic ore tailings has a great environmental pollution risk.

[0042] Example 1

[0043] In order to illustrate the effect of the present application on stabilizing heavy metal pollutants, the heavy metal solidification and stabilization agent and the use method according to the application are used to solidify and stabilize the heavy metal ions in the heavy metal standard solution.

[0044] The stabilizer is prepared in this example, and the method for solidifying the heavy metal ions in the heavy metal standard solution is as follows:

[0045] Step (1): Put 35 kg of polyaluminum ferric chloride, 15 kg of ferrous sulfate, 35 kg of calcium hydroxide, 14 kg of calcium carbonate, and 1 kg of iron oxide into a ball mill for grinding, all passing through a 200 mesh sieve to obtain a base component A;

[0046] Step (2): Take 200 ml of arsenic, cadmium, and zinc standard solutions with a mass concentration of 1000 mg / L produced by the National Non-ferrous Metal and Electronic Material Analysis and Test Center into a 1000 ml beaker;

[0047] Step (3): Take 150 g of the base component A obtained in step one and add it to the beaker in step (2), and stir uniformly;

[0048] Step (4): Add 10 mL of the reinforced component B (sodium tripolyphosphate) aqueous solution with a concentration of 0.3% to the material obtained by uniformly mixing the base component A and the heavy metal standard solution in step (3), and stir uniformly to obtain a stabilized body;

[0049] Step (5): Dry the stabilized body of step (4);

[0050] Step (6): Detect the stabilized body dried in step (5) by an X-ray diffractometer (XRD for short), and the results are shown in Figure 2 、 Figure 3 and Figure 4 The analysis chart can be seen from Figure 2 、 Figure 3 and Figure 4 that the stabilizer reacts with cadmium, arsenic, and zinc in the standard solution to generate a series of substances such as Cd4Al2O6Cl2·10H2O, Al2(AsO4)(OH)3·3H2O, and Zn5(OH)8Cl2·H2O.

[0051] Step (7): Perform leaching toxicity test on the stabilized body dried in step (5) according to the standard requirements of “Solid Waste Leaching Toxicity Leaching Method Horizontal Oscillation Method” (HJ557-2010). The related results are shown in Table 1. From the results, it can be seen that the concentration of arsenic, cadmium, and zinc in the leaching solution of the stabilized body is low, indicating that the stabilizer does not dissolve into water after reacting with arsenic, cadmium, and zinc, and the stabilizer has a good solidification and stabilization effect on arsenic, cadmium, and zinc.

[0052] Example 2

[0053] In order to illustrate the practical application effect of the present application, the heavy metal solidification and stabilization agent and the use method according to the present application are used to control the solidification and stabilization of heavy metal pollutants in a tin polymetallic mine tailings. The content of arsenic in the tin polymetallic mine tailings is 8616 mg / kg, the content of lead is 3523 mg / kg, the content of zinc is 4760 mg / kg, and the content of cadmium is 237 mg / kg.

[0054] In combination Figure 1 , the preparation of the solidification agent and the method for treating the tin polymetallic mine tailings are as follows:

[0055] Step (1): Put 35 kg of polyaluminum ferric chloride, 15 kg of ferrous sulfate, 35 kg of calcium hydroxide, 14 kg of calcium carbonate, and 1 kg of iron oxide into a ball mill for grinding, all of which pass through a 200 mesh screen to obtain a basic component A;

[0056] Step (2): Put 2000 g of dry tin polymetallic mine tailings into a blender;

[0057] Step (3): Add the stabilizer basic component A obtained in step (1) to the blender in step (2) and mix and stir the tin polymetallic mine tailings uniformly, and the amount of the basic component A is 1.0% of the mass of the tin polymetallic mine tailings, that is, the amount added is 20 g.

[0058] Step (4): Add 250 mL of 0.2% sodium tripolyphosphate aqueous solution to the material obtained by mixing and stirring the basic component A and the tin polymetallic mine tailings in step (3) uniformly, and the moisture content is about 25%;

[0059] Step (5): Cure the solidification and stabilization body, and the curing time is 24 hours.

[0060] Step (6) samples the cured tin polymetallic mine tailings after curing, and carries out leaching test according to the standard requirements of "Solid Waste Leaching Toxicity Leaching Method Horizontal Oscillation Method" (HJ557-2010). The relevant results are shown in Table 1. The arsenic, cadmium, lead, zinc and other heavy metals in the tin polymetallic mine tailings have two phases in terms of solubility, one is a kind or more of substances containing arsenic, cadmium, lead, zinc and other heavy metals that are easily soluble in water, and the other is a kind of arsenic, cadmium, lead or zinc containing heavy metal sulfide mineral that is difficult to dissolve in water; the latter kind of arsenic, cadmium, lead or zinc containing heavy metal sulfide mineral is also easily oxidized to form easily soluble substances in water under the condition of water and oxygen. After the basic component A of the stabilizer of the present application is uniformly mixed with the tin polymetallic mine tailings, the main role is to be uniformly distributed in the tailings particles. After adding the aqueous solution of the reinforcing component B (sodium tripolyphosphate), aluminum hydroxide, iron hydroxide and other multi-polar colloids are formed, which polymerize arsenic, cadmium, lead, zinc and other heavy metal ions and their easily soluble substances through chemical reactions and physical effects such as adsorption, adhesion, bridging, net trapping, etc. Reference is made to the EDS detection results of the lead-zinc mine tailings after stabilization Figure 5 Example, make arsenic, cadmium, lead, zinc and other heavy metals cannot be precipitated in water, play a stabilizing and solidifying effect; at the same time, the multi-polar colloids of aluminum hydroxide, iron hydroxide and the water-insoluble calcium carbonate and iron oxide in the stabilizer further prevent the arsenic, cadmium, lead or zinc containing heavy metal sulfide minerals in the tailings from being further oxidized to form easily soluble substances in water. As can be seen from Table 1, compared with the control example without adding stabilizer, due to the fine particle size, uniform distribution and fast effect of the stabilizer of the present application, the concentrations of arsenic, cadmium, lead and zinc, which are heavy metal pollutants in the leaching solution after 24 hours of curing, are lower than the limit values of "Integrated Wastewater Discharge Standard" (GB8978-1996) and also lower than the limit values of "Surface Water Environmental Quality Standard" Class III water standard; the solidification and stabilization effect of arsenic, cadmium, lead and zinc heavy metal pollutants is very obvious, which further proves that the mechanism of the stabilizing agent of the present application for solidification and stabilization of heavy metal pollutants in tin polymetallic mine tailings is clear and the effect is outstanding.

[0061] Example 3

[0062] In order to illustrate the practical application effect of the present application, the heavy metal solidification and stabilization agent and the use method according to the present application are used to control the solidification and stabilization of heavy metal pollutants in a certain tin polymetallic mine tailings. The content of arsenic in the certain tin polymetallic mine tailings is 8616 mg / kg, the content of lead is 3523 mg / kg, the content of zinc is 4760 mg / kg, and the content of cadmium is 237 mg / kg.

[0063] In combination Figure 1 , the preparation of the stabilizer and the method for treating the tin polymetallic mine tailings in this embodiment are as follows:

[0064] Step (1): Put polymeric aluminum ferric chloride 35 kg, ferrous sulfate 15 kg, calcium hydroxide 40 kg, calcium carbonate 9 kg, and iron oxide 1 kg into a ball mill for grinding, and pass all through a 200 mesh sieve to obtain a base component A;

[0065] Step (2): Put the tin polymetallic ore tailings with a dry weight of 5000 g into a blender;

[0066] Step (3): Add the base component A obtained in step (1) to the blender in step (2) and mix with the tin polymetallic ore tailings to obtain a mixture, and the amount of the base component A is 1.5% of the mass of the tin polymetallic ore tailings, i.e., 75 g is added.

[0067] Step (4): Add 1500 mL of an aqueous solution containing 0.2% sodium tripolyphosphate and 0.1% sodium silicate to the mixture of the base component A and the tin polymetallic ore tailings obtained in step (3), and stir until uniform, and the water content is about 30%;

[0068] Step (5): Cure the solidified and stabilized product for 24 hours.

[0069] Step (6): Sample the cured and stabilized product after curing, and perform leaching tests according to the standard requirements of "Solid Waste Leaching Toxicity Leaching Method Horizontal Oscillation Method" (HJ557-2010). The test results are shown in Table 1.

[0070] Example 4

[0071] In order to illustrate the practical application effect of the present application, the heavy metal solidification and stabilization agent and the use method according to the present application are used to control the solidification and stabilization of heavy metal pollutants in a certain tin polymetallic ore tailings. The content of arsenic in the certain tin polymetallic ore tailings is 8616 mg / kg, the content of lead is 3523 mg / kg, the content of zinc is 4760 mg / kg, and the content of cadmium is 237 mg / kg.

[0072] In combination Figure 1 , the preparation of the solidification agent and the method for treating the tin polymetallic ore tailings are as follows:

[0073] Step (1): Put polymeric aluminum ferric chloride 30 kg, ferrous sulfate 15 kg, calcium hydroxide 40 kg, calcium carbonate 13 kg, and iron oxide 2 kg into a ball mill for grinding, and pass all through a 200 mesh sieve to obtain a base component A;

[0074] Step (2): Put the tin polymetallic ore tailings with a dry weight of 20 kg into a blender;

[0075] Step (3) the stabilizer base component A obtained in step (1) is added to the blender in step (2) and mixed with the tin polymetallic ore tailings to be uniformly stirred, and the amount of the base component A is 1.5% of the mass of the tin polymetallic ore tailings, that is, the amount of addition is 300 g.

[0076] Step (4) 4000 mL of 0.3% sodium silicate aqueous solution is added to the material after the base component A and the tin polymetallic ore tailings in step (3) are uniformly mixed, and the moisture content is about 20%;

[0077] Step (5) the solidified and stabilized body is cured, and the curing time is 24 hours.

[0078] Step (6) the solidified and stabilized body is sampled, and the leaching test is carried out according to the standard requirements of “Solid Waste Leaching Toxicity Leaching Method Horizontal Oscillation Method” (HJ557-2010). The test results are shown in Table 1.

[0079] Example 5

[0080] In order to illustrate the practical application effect of the present application, the heavy metal solidification and stabilization agent and the use method according to the present application are used to control the solidification and stabilization of heavy metal pollutants in a certain tin polymetallic ore tailings. The content of arsenic in the certain tin polymetallic ore tailings is 8616 mg / kg, the content of lead is 3523 mg / kg, the content of zinc is 4760 mg / kg, and the content of cadmium is 237 mg / kg.

[0081] In combination Figure 1 , the preparation of the solidification agent and the method for treating the tin polymetallic ore tailings in this embodiment are as follows:

[0082] Step (1) 30 kg of polyaluminum ferric chloride, 15 kg of ferrous sulfate, 40 kg of calcium hydroxide, 13 kg of calcium carbonate and 2 kg of iron oxide are put into a ball mill for grinding, and all pass through a 200 mesh sieve to obtain a base component A;

[0083] Step (2) 1000 g of dry tin polymetallic ore tailings is put into a blender;

[0084] Step (3) the stabilizer base component A obtained in step (1) is added to the blender in step (2) and mixed with the tin polymetallic ore tailings to be uniformly stirred, and the amount of the base component A is 1.5% of the mass of the tin polymetallic ore tailings, that is, the amount of addition is 300 g.

[0085] Step (4) 250 mL of 0.3% sodium tripolyphosphate aqueous solution is added to the mixture obtained in step (3) to obtain a solidified and stabilized body, and the moisture content is about 25%;

[0086] Step (5) the solidified and stabilized body is cured, and the curing time is 24 hours.

[0087] Step (6) samples the curing and stabilizing body after maintenance, and carries out leaching test according to the standard requirements of "Solid Waste Leaching Toxicity Leaching Method Horizontal Oscillation Method" (HJ557-2010). The test results are shown in Table 1.

[0088] Table 1 Stabilization test results of tin polymetallic tailings (unit: mg / L)

[0089] .

[0090] The above data and table show that when the heavy metal pollutants are one or more of cadmium, lead, arsenic and zinc, the content of arsenic in the tailings is ≦10000 mg / kg, the content of lead is ≦5000 mg / kg, the content of zinc is ≦5000 mg / kg, and the stabilizer particles are less than 200 mesh, the tin polymetallic tailings can be better mixed and distributed between various minerals, and under the action of the reinforcing component and water, the polyaluminum ferric chloride and calcium hydroxide hydrolyze and immediately react with heavy metals such as cadmium, arsenic, lead and zinc to generate a series of stable substances such as Cd4Al2O6Cl2·10H2O, Al2(AsO4)(OH)3·3H2O and Zn5(OH)8Cl2·H2O, and details are shown in Figure 2 、 Figure 3 、 Figure 4 Examples. At the same time, complex agglomeration, polymerization, physical adsorption and other mineralization effects are generated, and reference is made to the EDS detection results of the lead-zinc tailings after stabilization Figure 5 Examples. Arsenic, copper and lead are generated into multi-core polymers with iron and aluminum, and are solidified together, which greatly reduces the toxicity and leaching rate of heavy metals; sodium tripolyphosphate is selected as a reinforcing agent, which cooperates with the basic component A to make the heavy metal minerals generated in the solidification and stabilization process more stable. The tin polymetallic tailings are changed from Class II solid waste to Class I solid waste, and the environmental pollution risk is greatly reduced. As can be seen from the examples (Table 1), the concentration of heavy metal pollutants in the leaching solution after stabilization is far lower than the limit value of "Integrated Wastewater Discharge Standard" (GB8978-1996), and is also lower than the corresponding limit value of "Surface Water Environmental Quality Standard" Class III water standard. The concentrations of cadmium, lead, arsenic and zinc in the leaching solution are reduced from 3.725 mg / L, 0.31 mg / L, 2.23 mg / L and 1.87 mg / L before solidification and stabilization to 0.0032 mg / L, 0.0023 mg / L, 0.0046 mg / L and 0.041 mg / L or less after stabilization, and the solidification rate reaches 99.91%, 99.26%, 99.79% and 97.81%. It can be seen that the stabilizer for controlling heavy metal pollution of tin polymetallic tailings is a kind of heavy metal solidification and stabilization agent which has quick effect and good effect.

[0091] The above-described embodiments are merely preferred embodiments of the present application, and the protection scope of the present application is not limited thereto. Any equivalent substitutions or transformations made by those skilled in the art based on the present application are within the protection scope of the present application. The protection scope of the present application is subject to the claims.

Claims

1. A method for controlling heavy metal pollution of tin polymetallic ore tailings, characterized in that: it comprises a stabilizer; the stabilizer is composed of a basic component A and a reinforcing component B; polyaluminum ferric chloride 35 kg, ferrous sulfate 15 kg, calcium hydroxide 35 kg, calcium carbonate 14 kg, and iron oxide 1 kg are put into a ball mill for grinding, and all pass through a 200-mesh screen to obtain the basic component A; the polyaluminum ferric chloride is an industrial product, wherein the content of aluminum oxide is >= 26%, the content of iron oxide is 3%-6%, the base degree is >= 65%, and the content of arsenic is <= 0.0003%; the reinforcing component B is 0.5% sodium tripolyphosphate aqueous solution; when the content of arsenic in the tin polymetallic ore tailings is 8616 mg / kg, the content of lead is 3523 mg / kg, the content of zinc is 4760 mg / kg, and the content of cadmium is 237 mg / kg, 20 g of the basic component A is mixed with 2000 g of the tin polymetallic ore tailings and stirred uniformly; 250 mL of 0.5% sodium tripolyphosphate aqueous solution is added to the mixture of the basic component A and the tin polymetallic ore tailings, the moisture content is controlled to be 25%, and the pH is controlled to be 7.5-9; and the solidified and stabilized product is cured for 24 hours.

2. The method according to claim 1, characterized in that: the basic component A is prepared by the following steps: grinding polyaluminum ferric chloride 35 kg, ferrous sulfate 15 kg, calcium hydroxide 35 kg, calcium carbonate 14 kg, and iron oxide 1 kg in a ball mill, and passing all through a 200-mesh screen.

3. The method according to claim 1, characterized in that: the polyaluminum ferric chloride is an industrial product, wherein the content of aluminum oxide is >= 26%, the content of iron oxide is 3%-6%, the base degree is >= 65%, and the content of arsenic is <= 0.0003%.

4. The method according to claim 1, characterized in that: the reinforcing component B is 0.5% sodium tripolyphosphate aqueous solution.

5. The method according to claim 1, characterized in that: the content of arsenic in the tin polymetallic ore tailings is 8616 mg / kg, the content of lead is 3523 mg / kg, the content of zinc is 4760 mg / kg, and the content of cadmium is 237 mg / kg.

6. The method according to claim 1, characterized in that: the moisture content is controlled to be 25%, and the pH is controlled to be 7.5-9.

7. The method according to claim 1, characterized in that: the curing time is 24 hours. ​

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