A collaborative treatment method for low-concentration nickel-containing wastewater

Abstract

The invention discloses a collaborative treatment method for low-concentration nickel-containing wastewater. The nickel-containing wastewater is pumped into a reaction tank, carbide slag is added under uniform stirring to carry out a neutralization precipitation reaction, copper slag is added, and ultrasonic collaborative catalysis is used to break the complex nickel, coal slag and pine sawdust are added and aged, and the pH value of the solution is adjusted to 8-9 with acid. The main components of the precipitated slag are nickel hydroxide and calcium sulfate. The precipitated slag is used as a slag-forming agent in the nickel-iron pyrometallurgy process, and the nickel in the slag is recycled to achieve the effect of no waste residue discharge. The method of the invention can reduce the concentration of nickel ions in the wastewater from 50-1500ppm to below 0.5ppm, with a nickel removal rate of more than 99.9%, and the nickel ion concentration in the wastewater meets the emission standard. The raw materials used in the invention are all general industrial solid wastes, the operation is simple, the running cost is low, and the method is economical and efficient. It complies with the national environmental protection concept of treating waste with waste and comprehensively utilizing solid waste resources, is suitable for removing nickel ions in wastewater, and has good application prospects.

Description

Technical Field

[0001] The present invention relates to a collaborative treatment method for low-concentration nickel-containing wastewater, in particular to a method for collaboratively treating low-concentration nickel-containing wastewater to remove nickel from the wastewater, belonging to the technical field of hydrometallurgy. Background Art

[0002] In the production process of wet nickel smelting, solvent extraction is used to comprehensively separate metallic impurity elements such as Zn, Cr, Cd, Mn, Fe, Mg, and Ca. Organic substances such as extractants and diluent kerosene will remain in the stripping wastewater. These organic substances exist in the stripping solution in the form of oil film, dispersed oil, and dissolved oil. Some organic substances form relatively stable complexes with nickel. The nickel-containing stripping wastewater generated in the wet nickel smelting process is divided into two categories. One is nickel-ion-containing wastewater, mainly nickel sulfate and nickel chloride, and nickel exists in the form of ions; the other is complex nickel wastewater, in which nickel forms stable complexes with organic substances such as extractants and diluent kerosene. Complex nickel is difficult to separate and remove from wastewater, and deep removal is difficult. The method of using only traditional alkaline precipitation to convert nickel ions into hydroxides for removal is inefficient and ineffective, and it is difficult to meet emission standards. In addition, nickel-containing wastewater is extremely harmful to human body and ecology, and is a major problem in wastewater treatment. Numerous methods for treating nickel-containing wastewater have been disclosed in the prior art, but these methods generally suffer from complex processes, poor treatment of complexed nickel, low nickel removal rates, and poor stability. Therefore, developing a method capable of deeply removing complexed nickel from stripping wastewater has become an urgent technical challenge. Summary of the Invention

[0003] In view of the problems and shortcomings of the existing technology, the present invention provides a collaborative treatment method for low-concentration nickel-containing wastewater, which has a simple process, thorough complex breaking, high nickel removal rate, stable effect and low cost.

[0004] The technical solutions of the present invention are as follows:

[0005] A collaborative treatment method for low-concentration nickel-containing wastewater, the specific steps are as follows:

[0006] The nickel-containing wastewater is pumped into the reaction tank, and carbide slag is slowly added under uniform stirring to carry out neutralization and precipitation reaction until the pH value is 10-12 and remains stable for more than 0.5 hours, so that the free nickel ions are neutralized and precipitated into the slag;

[0007] Then copper slag is added and ultrasonic waves are used to catalyze and break the nickel complex, so that the nickel in the wastewater is completely converted into nickel hydroxide precipitation;

[0008] After adding coal slag and pine sawdust and aging for 1 to 2 hours, trace nickel hydroxide suspended particles are adsorbed, and the pH value of the solution is adjusted to 8 to 9 with acid. The main components of the precipitated slag are nickel hydroxide, calcium sulfate, etc., which can be used as a slag-making agent in the nickel-iron smelting process to recycle the nickel in the precipitated slag and achieve the effect of no waste slag discharge. This method can reduce the concentration of free nickel ions in the wastewater from 50 to 1500 ppm to below 0.5 ppm, with a nickel removal rate of more than 99.9%. The removal effect is significant, and one-time removal can be achieved, realizing industrial application, fundamentally avoiding incomplete destruction of complexed nickel, solving the problem of excessive nickel content in discharged wastewater, and ensuring that the free nickel ion content in the discharged wastewater meets the discharge standard.

[0009] Preferably, the concentration of free nickel ions in the nickel-containing wastewater is 50 to 1500 ppm.

[0010] Preferably, the rotation speed of the uniform stirring is 250-300 r / min.

[0011] Preferably, the Ca(OH)2 content (mass fraction) in the carbide slag is greater than 90%, and the Al2O3 content (mass fraction) is greater than 90%.

[0012] 3.5%-5.5%, and the rest are unavoidable impurities; the particle size of the carbide slag is 0.01-2mm.

[0013] Preferably, the composition and mass percentage of the copper slag are: 0.6-1.5% Cu, 2-4% CaO, 2-5% Al2O3, 30-40% Fe, 30-35% SiO2, and the rest are inevitable impurities such as a small amount of zinc and sulfur; its mineral composition mainly includes: magnetite (Fe3O4), fayalite (Fe2SiO4), pyroxene (CaFeAlSi2O6), calcium magnesium pyroxene (CaMgSi2O6), magnesia (Mg3Al2(SiO4)3), zinc iron spinel (ZnFe2O4), etc.; the copper slag particle size is 10-200 mesh.

[0014] Preferably, the amount of copper slag added is 10-30 g / L.

[0015] Preferably, the ultrasonic power of the ultrasonic synergistic catalytic decomposition of the nickel complex is 200-600W, and the ultrasonic synergistic catalytic decomposition of the nickel complex has a stable reaction time of 1 hour.

[0016] Preferably, the composition and mass percentage of the coal slag are: 40-50% SiO2, 30-35% Al2O3, 4-20% Fe2O3, 1-5% CaO, and the remainder is inevitable impurities such as a small amount of magnesium, sulfur, carbon, etc.; its mineral composition mainly includes: anorthite, quartz, mullite, magnetite and pyrite, a large amount of silicon-containing glass (Al2O3·2SiO2) and active SiO2, active Al2O3 and a small amount of unburned coal, etc.; the coal slag particle size is 0.1-2 mm.

[0017] Preferably, the amount of coal slag added is 20-50 g / L.

[0018] Preferably, the particle size of the pine sawdust is 1 to 2 mm.

[0019] Preferably, the amount of pine sawdust added is 10-20 g / L.

[0020] The present invention adopts calcium carbide slag to neutralize and precipitate free nickel ions in wet nickel smelting wastewater, uses ultrasonic copper slag to synergistically catalyze and break down complex nickel, and adds coal slag and pine sawdust to adsorb free trace nickel hydroxide suspended particles to further remove nickel ions in wet nickel smelting wastewater. The method of the present invention can reduce the nickel ion concentration in the wastewater from 50 to 1500 ppm to below 0.5 ppm, with a nickel removal rate of over 99.9%. The removal effect is significant, and one-time removal can be achieved, thereby realizing industrial application, fundamentally avoiding the problem of incomplete complex nickel breaking and excessive nickel content in discharged wastewater. Moreover, the raw materials calcium carbide slag, copper slag, coal slag, pine sawdust, etc. used in the method of the present invention are all general industrial solid wastes, with low operating costs, simple operation, and economical and efficient operation. It complies with the national environmental protection concept of treating waste with waste and comprehensively utilizing solid waste resources, is suitable for removing nickel ions in wastewater, and has good application prospects.

[0021] The beneficial effects of the present invention are:

[0022] 1. The method of the present invention is used to directly remove nickel ions from wet nickel smelting wastewater. The removal effect is significant and can be achieved in one go, making it industrially applicable. It fundamentally avoids the problem of incomplete removal of complexed nickel and excessive nickel content in discharged wastewater, reducing the nickel concentration in the wastewater from 50 to 1500 ppm to below 0.5 ppm, with a nickel removal rate of over 99.9%.

[0023] 2. The raw materials used in the method of the present invention, such as calcium carbide slag, copper slag, coal slag, pine sawdust, etc., are all general industrial solid wastes. The method has low operating cost, simple operation, and is economical and efficient. It conforms to the national environmental protection concept of treating waste with waste and comprehensively utilizing solid waste resources. It is suitable for removing nickel ions in wastewater and has good application prospects.

[0024] 3. The main components of the precipitated slag produced by the present invention are nickel hydroxide, calcium sulfate, etc., which can be used as a slag-forming agent in the nickel-iron smelting process to recycle the nickel in the precipitated slag, achieving the effect of no waste slag discharge.

[0025] 4. The conventional hydrometallurgical equipment used in the present invention has a simple structure, low cost and easy maintenance. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a process flow chart. DETAILED DESCRIPTION

[0027] In order to further understand the present invention, the present invention is described below in conjunction with embodiments. However, it should be understood that these descriptions are only for further illustrating the features and advantages of the present invention, rather than limiting the claims of the present invention.

[0028] The raw materials of the present invention include: calcium carbide slag, copper slag, coal slag, pine sawdust, etc. The materials provided by the present invention have the advantages of good neutralization and precipitation effect, high catalytic efficiency of breaking complex nickel, strong adsorption capacity, etc. Therefore, this scheme has good effect of breaking complex nickel and improving the removal of nickel ions in wet nickel refining wastewater. The removal effect is significant, and it can achieve one-time removal, realize industrial application, and fundamentally avoid the problems of incomplete complex nickel breaking and excessive nickel content in discharged wastewater. The present invention follows the environmental protection concept of treating waste with waste, that is, it treats general solid wastes such as calcium carbide slag, copper slag, coal slag, pine sawdust, etc. generated by the smelting and chemical industries, and realizes the comprehensive utilization of solid waste resources; without increasing the labor intensity of workers, the ability to remove nickel ions in wet nickel refining wastewater is improved, thereby reducing production costs.

[0029] In the present invention, the carbide slag is the carbide slag produced in the acetylene production process well known to those skilled in the art, and is a general solid waste slag. There is no particular limitation on its source in the present invention. However, in order to ensure the neutralization and precipitation removal effect of nickel ions and not affect normal production capacity, the carbide slag used in the embodiment has a Ca(OH)2 content greater than 90%, an Al2O3 content of 3.5%-5.5%, and the rest are unavoidable impurities; the particle size is 0.01-2 mm; the amount of carbide slag added is not limited, and the pH value at the reaction endpoint is controlled to be stable between 10 and 12. The carbide slag plays a role in adjusting the pH value and precipitating Ni 2+ The reaction process is as follows:

[0030] Ni 2+ +Ca(OH)2=Ni(OH)2↓+Ca 2+

[0031] In the present invention, the copper slag is the copper slag produced in the copper pyrometallurgical smelting process well known to those skilled in the art, which is a general solid waste slag and has no special restrictions on its source. However, in order to ensure the catalytic removal effect of the complex nickel and not affect the normal production capacity, the composition and mass percentage of the copper slag used in the embodiment are: 0.6-1.5% Cu, 2-4% CaO, 2-5% Al2O3, 30-40% Fe, 30-35% SiO2, and the rest are inevitable impurities such as a small amount of zinc and sulfur; its mineral composition mainly includes: magnetite (Fe3O4), fayalite (Fe2SiO4), pyroxene (CaFeAlSi2O6), calcium magnesium pyroxene (CaMgSi2O6), magnesia (Mg3Al2(SiO4)3), zinc iron spinel (ZnFe2O4), etc.; the copper slag particle size is 10-200 mesh; the amount of copper slag added is 10-30g / L; the copper slag plays a role in catalytic removal of the complex nickel.

[0032] In the present invention, the coal slag is the coal slag produced in the coal combustion process well known to those skilled in the art, and is a general solid waste residue. There is no special restriction on its source in the present invention. However, in order to ensure the adsorption and removal effect of free trace nickel hydroxide suspended particles and not affect normal production capacity, the composition and mass percentage content of the adsorbent coal slag used in the embodiment are: 40-50% SiO2, 30-35% Al2O3, 4-20% Fe2O3, 1-5% CaO, and the rest are unavoidable impurities such as a small amount of magnesium, sulfur, carbon, etc. Its mineral composition mainly includes: calcium feldspar, quartz, mullite, magnetite and pyrite, a large amount of silicon-containing glass (Al2O3·2SiO2) and active SiO2, active Al2O3 and a small amount of unburned coal, etc.; the coal slag particle size is 0.1-2 mm; the coal slag addition amount is 20-50 g / L; the coal slag plays the role of adsorbing and removing trace nickel hydroxide suspended particles.

[0033] In the present invention, pine sawdust is pine sawdust produced in the wood processing process that is well known to those skilled in the art. It is a general solid waste residue and its source is not particularly limited in the present invention. However, in order to ensure the adsorption and removal effect of free trace nickel hydroxide suspended particles and not affect normal production capacity, the pine sawdust used in the embodiment has a particle size of 1 to 2 mm; the addition amount is 10 to 20 g / L; the pine sawdust plays a role in adsorbing and removing trace nickel hydroxide suspended particles. Because the pine sawdust particles are relatively loose, they can also improve the filtration performance of the solution, shorten the liquid-solid separation filtration time, and improve production efficiency.

[0034] Example 1

[0035] like Figure 1As shown, 1000L of wet nickel smelting wastewater with a nickel concentration of 1000ppm was pumped into a complex breaking reaction tank through a pump, stirring was started, and at a speed of 300r / min, calcium carbide slag with a particle size of 0.01 to 2mm was uniformly added to neutralize and precipitate free nickel ions. The precipitation pH value was controlled to be 11, and the neutralization precipitation stabilization time was 0.5h, so that the free nickel ions in the wastewater were precipitated as nickel hydroxide.

[0036] Then, the ultrasonic wave was turned on and the ultrasonic power was controlled to 500W. About 15kg of copper slag with a particle size of 10-200 mesh was uniformly added to the decomposition reaction tank to carry out a synergistic catalytic decomposition of nickel complexes. The pH value of the decomposition of nickel complexes was 11. The catalytic decomposition reaction was stabilized for 1 hour, so that the nickel in the wastewater was completely precipitated into nickel hydroxide.

[0037] Then, 25 kg of coal slag with a particle size of 0.1 to 2 mm and 12 kg of pine sawdust with a particle size of 1 to 2 mm were added to absorb the trace suspended nickel hydroxide particles in the solution, and the adsorption and aging time was controlled to be 1.5 hours.

[0038] Finally, the endpoint pH value of the solution was adjusted to 8-9 with industrial concentrated sulfuric acid to obtain wastewater that met the discharge standards. The nickel ion content in the wastewater was 0.2ppm, and the nickel removal rate was as high as 99.98%.

[0039] The main components of the separated precipitated slag are nickel hydroxide, calcium sulfate, etc., which can be used as a slag-forming agent in the nickel-iron smelting process to recycle the nickel in the precipitated slag and achieve the effect of no waste slag discharge.

[0040] Example 2

[0041] 1000L of wet nickel smelting wastewater containing 1200ppm of nickel was pumped into a decomposition reaction tank. Stirring was started. At a speed of 250r / min, carbide slag with a particle size of 0.01 to 2mm was first added at a uniform speed to neutralize and precipitate free nickel ions. The precipitation pH was controlled to 12, and the neutralization precipitation was stabilized for 0.5h to precipitate the free nickel ions in the wastewater into nickel hydroxide.

[0042] Then, the ultrasonic wave was turned on and the ultrasonic power was controlled to 450W. About 20kg of copper slag with a particle size of 10-200 mesh was uniformly added to the decomposition reaction tank to carry out a synergistic catalytic decomposition of nickel complexes. The pH value of the decomposition of nickel complexes was 12. The catalytic decomposition reaction was stabilized for 1 hour, so that the nickel in the wastewater was completely precipitated into nickel hydroxide.

[0043] Then, 40 kg of coal slag with a particle size of 0.1 to 2 mm and 15 kg of pine sawdust with a particle size of 1 to 2 mm were added to adsorb the trace amount of nickel hydroxide suspended particles free in the solution, and the adsorption and aging time was controlled to be 2 hours;

[0044] Finally, the endpoint pH value of the solution was adjusted to 8-9 with industrial concentrated sulfuric acid to obtain the wastewater that met the discharge standards. The nickel ion content in the wastewater was 0.3ppm, and the nickel removal rate was as high as 99.98%.

[0045] The main components of the separated precipitated slag are nickel hydroxide, calcium sulfate, etc., which can be used as a slag-forming agent in the nickel-iron smelting process to recycle the nickel in the precipitated slag and achieve the effect of no waste slag discharge.

[0046] Example 3

[0047] 1000L of wet nickel smelting wastewater containing 1500ppm of nickel was pumped into a decomposition reaction tank. Stirring was started. At a speed of 300r / min, carbide slag with a particle size of 0.01 to 2mm was first added at a uniform speed to neutralize and precipitate free nickel ions. The precipitation pH was controlled to 10, and the neutralization precipitation was stabilized for 0.5h to precipitate the free nickel ions in the wastewater into nickel hydroxide.

[0048] Then, the ultrasonic wave was turned on and the ultrasonic power was controlled to 600W; about 30kg of copper slag with a particle size of 10 to 200 mesh was uniformly added to the decomposition reaction tank to carry out a synergistic catalytic decomposition of nickel complexes. The pH value of the decomposition of nickel complexes was 10, and the catalytic decomposition reaction was stabilized for 1 hour, so that the nickel in the wastewater was completely precipitated into nickel hydroxide;

[0049] Then, 50 kg of coal slag with a particle size of 0.1 to 2 mm and 20 kg of pine sawdust with a particle size of 1 to 2 mm were added to adsorb the trace amount of nickel hydroxide suspended particles free in the solution, and the adsorption and aging time was controlled to be 1.5 hours;

[0050] Finally, the endpoint pH value of the solution was adjusted to 8-9 with industrial concentrated sulfuric acid to obtain the wastewater that met the discharge standards. The nickel ion content in the wastewater was 0.1ppm, and the nickel removal rate was as high as 99.99%.

[0051] The main components of the separated precipitated slag are nickel hydroxide, calcium sulfate, etc., which can be used as a slag-forming agent in the nickel-iron smelting process to recycle the nickel in the precipitated slag and achieve the effect of no waste slag discharge.

[0052] Example 4

[0053] 1000L of wet nickel smelting wastewater containing 800ppm nickel was pumped into a decomposition reaction tank. Stirring was started. At a speed of 250r / min, carbide slag with a particle size of 0.01 to 2mm was first added at a uniform speed to neutralize and precipitate free nickel ions. The precipitation pH was controlled to 11. The neutralization precipitation was stabilized for 0.5h, so that the free nickel ions in the wastewater were precipitated as nickel hydroxide.

[0054] Then, the ultrasonic wave was turned on and the ultrasonic power was controlled to 300W; about 20kg of copper slag with a particle size of 10-200 mesh was uniformly added to the decomposition reaction tank to carry out a synergistic catalytic decomposition of nickel complexes. The pH value of the decomposition of nickel complexes was 11, and the catalytic decomposition reaction was stabilized for 1 hour, so that the nickel in the wastewater was completely precipitated into nickel hydroxide;

[0055] Then, 30 kg of coal slag with a particle size of 0.1 to 2 mm and 15 kg of pine sawdust with a particle size of 1 to 2 mm were added to adsorb the trace amount of nickel hydroxide suspended particles free in the solution, and the adsorption and aging time was controlled to be 1 hour;

[0056] Finally, the endpoint pH value of the solution was adjusted to 8-9 with industrial concentrated sulfuric acid to obtain the wastewater that met the discharge standards. The nickel ion content in the wastewater was 0.2ppm, and the nickel removal rate was as high as 99.98%.

[0057] The main components of the separated precipitated slag are nickel hydroxide, calcium sulfate, etc., which can be used as a slag-forming agent in the nickel-iron smelting process to recycle the nickel in the precipitated slag and achieve the effect of no waste slag discharge.

[0058] Example 5

[0059] 1000L of wet nickel smelting wastewater containing 200ppm of nickel was pumped into a decomposition reaction tank. Stirring was started. At a speed of 300r / min, carbide slag with a particle size of 0.01 to 2mm was first added at a uniform speed to neutralize and precipitate free nickel ions. The precipitation pH was controlled to 12. The neutralization precipitation was stabilized for 0.5h, so that the free nickel ions in the wastewater were precipitated as nickel hydroxide.

[0060] Then, the ultrasonic wave was turned on and the ultrasonic power was controlled to 250W. About 15kg of copper slag with a particle size of 10-200 mesh was uniformly added to the decomposition reaction tank to carry out a synergistic catalytic decomposition of nickel complexes. The pH value of the decomposition of nickel complexes was 11. The catalytic decomposition reaction was stabilized for 1 hour, so that the nickel in the wastewater was completely precipitated into nickel hydroxide.

[0061] Then, 25 kg of coal slag with a particle size of 0.1 to 2 mm and 15 kg of pine sawdust with a particle size of 1 to 2 mm were added to adsorb the trace amount of nickel hydroxide suspended particles free in the solution, and the adsorption and aging time was controlled to be 2 hours;

[0062] Finally, the endpoint pH value of the solution was adjusted to 8-9 with industrial concentrated sulfuric acid to obtain the wastewater that met the discharge standards. The nickel ion content in the wastewater was 0.1ppm, and the nickel removal rate was as high as 99.95%.

[0063] The main components of the separated precipitated slag are nickel hydroxide, calcium sulfate, etc., which can be used as a slag-forming agent in the nickel-iron smelting process to recycle the nickel in the precipitated slag and achieve the effect of no waste slag discharge.

[0064] Example 6

[0065] 1000L of wet nickel smelting wastewater containing 50ppm nickel was pumped into a decomposition reaction tank, stirring was started, and at a speed of 250r / min, calcium carbide slag with a particle size of 0.01 to 2mm was uniformly added to neutralize and precipitate free nickel ions. The precipitation pH was controlled to 11, and the neutralization precipitation was stabilized for 1h, so that the free nickel ions in the wastewater were precipitated as nickel hydroxide.

[0066] Then, the ultrasonic wave was turned on and the ultrasonic power was controlled to 200W. About 10kg of copper slag with a particle size of 10-200 mesh was uniformly added to the decomposition reaction tank to carry out a synergistic catalytic decomposition of nickel complexes. The pH value of the decomposition of nickel complexes was 11. The catalytic decomposition reaction was stabilized for 1 hour, so that the nickel in the wastewater was completely precipitated into nickel hydroxide.

[0067] Then, 20 kg of coal slag with a particle size of 0.1 to 2 mm and 10 kg of pine sawdust with a particle size of 1 to 2 mm were added to adsorb the trace amount of nickel hydroxide suspended particles free in the solution, and the adsorption and aging time was controlled to be 2 hours;

[0068] Finally, the endpoint pH value of the solution was adjusted to 8-9 with industrial concentrated sulfuric acid to obtain the wastewater that met the discharge standards. The nickel ion content in the wastewater was 0.05ppm, and the nickel removal rate was as high as 99.9%.

[0069] The main components of the separated precipitated slag are nickel hydroxide, calcium sulfate, etc., which can be used as a slag-forming agent in the nickel-iron smelting process to recycle the nickel in the precipitated slag and achieve the effect of no waste slag discharge.

[0070] The above describes the specific embodiments of the present invention in detail, but the present invention is not limited to the above embodiments. Various changes can be made within the knowledge of ordinary technicians in this field without departing from the scope of the present invention.

Claims

1. A collaborative treatment method for low-concentration nickel-containing wastewater, characterized in that: The specific steps are as follows: The nickel-containing wastewater is pumped into the reaction tank, and carbide slag is added under uniform stirring to carry out neutralization and precipitation reaction until the pH value is 10-12 and remains stable for more than 0.5h; Then, copper slag is added, and ultrasonic synergistic catalysis is used to break down the complexed nickel. Coal slag and pine sawdust are then added and aged for 1-2 hours. The pH value of the solution is then adjusted to 8-9 with acid. The precipitated slag is recycled as a slagging agent in the nickel-iron pyrometallurgical smelting process, and the nickel ion concentration in the wastewater meets the discharge standard. The ultrasonic power of the ultrasonic synergistic catalytic decomposition of the complexed nickel is 200-600W, and the synergistic catalytic reaction time is 1h; The Ca(OH)2 content in the carbide slag is greater than 90%, the Al2O3 content is 3.5%-5.5%, and the rest are unavoidable impurities; the particle size of the carbide slag is 0.01-2 mm; The composition and mass percentage of the copper slag are: 0.6-1.5% Cu, 2-4% CaO, 2-5% Al2O3, 30-40% Fe, 30-35% SiO2, and the remainder is unavoidable impurities; the copper slag particle size is 10-200 mesh; the amount of the copper slag added is 10-30 g / L; The composition and mass percentage of the coal slag are 40-50% SiO2, 30-35% Al2O3, 4-20% Fe2O3, 1-5% CaO, and the remainder is unavoidable impurities; the particle size of the coal slag is 0.1-2 mm; and the amount of the coal slag added is 20-50 g / L.

2. The collaborative treatment method for low-concentration nickel-containing wastewater according to claim 1, characterized in that: The nickel ion concentration in the nickel-containing wastewater is 50 to 1500 ppm.

3. The collaborative treatment method for low-concentration nickel-containing wastewater according to claim 1, characterized in that: The uniform stirring speed is 250-300 r / min.

4. The collaborative treatment method for low-concentration nickel-containing wastewater according to claim 1, characterized in that: The particle size of the pine sawdust is 1-2 mm, and the amount of the pine sawdust added is 10-20 g / L.

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