Resource utilization method of copper-containing waste slag

Abstract

The present invention provides a method for resource utilization of copper-containing waste slag, which relates to the field of waste slag treatment. The method involves adding copper-containing waste slag to mine acidic water, slurrying, flocculation, and thickening to obtain an iron removal underflow and an iron removal overflow. The iron removal underflow is mixed with the neutralization overflow and washed, and then dehydrated by filtration to obtain a first press filtrate and a first press filtrate residue that meets the requirements of general industrial solid waste. The first press filtrate and the iron removal overflow are then subjected to a sulfidation copper collection treatment to obtain a sulfidation overflow, a second press filtrate, and a second press filtrate residue that can be collected as copper slag. The sulfidation overflow and the second press filtrate are then neutralized to obtain a neutralization overflow that meets emission standards and a third press filtrate, as well as a third press filtrate residue that meets the requirements of general industrial solid waste. In this way, the present invention can utilize mine acidic water to treat copper-containing waste slag, and while performing harmless and resourceful treatment on the copper-containing waste slag, achieve deep purification of mine acidic water.

Description

Technical Field

[0001] The present invention relates to the technical field of harmless treatment of waste slag, and in particular to a method for resource utilization of copper-containing waste slag. Background Art

[0002] Sulfur-rich deposits in non-ferrous metal mines contain a large number of sulfide minerals. Under the influence of air, water, and microorganisms, these minerals undergo a series of physical, chemical, and biochemical reactions, including weathering, leaching, oxidation, and hydrolysis, gradually forming acidic water containing sulfuric acid, which seriously pollutes the surrounding environment. To treat this acidic water, simple neutralization methods are commonly used. However, this causes a large amount of valuable substances, such as copper, to enter the neutralization precipitate. This not only prevents the effective recovery of valuable metals, but also poses a risk of leaching toxicity exceeding the requirements for general industrial solid waste, creating a potential environmental pollution risk. Therefore, the harmless treatment and resource utilization of this copper-rich neutralization slag (copper grade greater than 1%) is a common challenge in the treatment of acidic water in older mines.

[0003] Patent publication number CN114737062A provides a method for recovering valuable elements from neutralized slag produced by treating acidic mine wastewater. This patent uses several steps, including acid leaching of the neutralized slag → neutralization to remove iron and arsenic → sulfidation to collect copper → evaporation and crystallization, to comprehensively recover the copper, iron, and small amounts of arsenic and zinc enriched in the slag. The recovery rate of copper and iron is over 95%, and the arsenic removal rate is over 90%. However, when conducting acid leaching, this patent uses a mixture of acidic wastewater from the original mine and concentrated sulfuric acid as the leaching agent. The additional concentrated sulfuric acid not only increases the treatment cost, but also requires increasing the temperature of the leaching reaction, increasing the difficulty of wastewater treatment. At the same time, when conducting acid leaching, this patent controls the leaching pH value within a relatively low range, so that after the harmful substances such as iron and arsenic in the neutralized slag are dissolved, secondary iron and arsenic removal is required, which increases the complexity of the entire process and there is a risk that the iron-arsenic slag will be a hazardous waste (the toxic copper concentration of the iron-arsenic slag leached exceeds the standard). Finally, this patent only provides the control process parameter ranges for related processes such as acid leaching and sulfide copper recovery, and fails to establish an internal logical control relationship. There is a risk that the process parameters cannot be effectively controlled during the technical engineering application.

[0004] In view of this, it is necessary to design an improved method for resource utilization of copper-containing waste slag to solve the above problems. Summary of the Invention

[0005] In view of the above-mentioned defects of the prior art, the purpose of the present invention is to provide a method for resource utilization of copper-containing waste slag. According to the pollution endowment characteristics of copper-containing waste slag, mine acidic water is used for waste treatment, and through combined treatment with physical and chemical methods, the environmental pollution risks of copper-containing waste slag are reduced, the valuable substance copper in the waste slag is effectively recovered, and comprehensive treatment of acidic water is achieved.

[0006] To achieve the above object, the present invention provides a method for resource utilization of copper-containing waste slag, comprising the following steps:

[0007] S1. Adding copper-containing waste slag to acidic water from a mine, and fully stirring and slurrying in a slurry mixing tank to obtain a copper-containing waste slag liquid; adding a flocculant to the copper-containing waste slag liquid, and obtaining a deironing underflow and a deironing overflow after solid-liquid separation in a deironing thickener; mixing at least a portion of the deironing underflow and the neutralization overflow in a predetermined mass ratio for washing, and performing a filter press dehydration operation after washing to obtain a first filter press residue and a first filter press liquid;

[0008] S2, inputting the iron removal overflow obtained in step S1 and the first press filtrate into a sulfidation reaction tank, adding a sulfiding agent to adjust the ORP value, and obtaining a sulfided copper-collecting turbid liquid; adding a flocculant to the sulfided copper-collecting turbid liquid, and obtaining a sulfided underflow and a sulfided overflow after solid-liquid separation in a sulfidation thickener; and subjecting at least a portion of the sulfided underflow to a filter press dehydration treatment to obtain a second filter press residue and a second filter press liquid;

[0009] S3. Inputting the sulfide overflow and the second press filtrate obtained in step S2 into a neutralization reaction tank, adjusting the pH value to obtain a neutralized turbid liquid; adding a flocculant to the neutralized turbid liquid, and obtaining a neutralization underflow and a neutralization overflow after solid-liquid separation in a neutralization thickener; and subjecting at least a portion of the neutralization underflow to a filter press dehydration treatment to obtain a third filter press residue and a third press filtrate.

[0010] As a further improvement of the present invention, in step S1, the mass concentration of the solid phase in the copper-containing waste liquid is 10% to 40%, and the pH value of the liquid phase in the copper-containing waste liquid is 3.4 to 3.6.

[0011] As a further improvement of the present invention, in step S1, the sufficient stirring time is more than 1 hour; the proportional relationship between the volume of the mine acidic water and the mass of the copper-containing waste slag is determined according to the following formula:

[0012]

[0013] Among them, α1 is the first correction factor, and its value range is 0.015~0.050; pH1 is the pH value of the mine acidic water, V is the volume of the mine acidic water, pH2 is the pH value of the copper-containing waste slag, m is the mass of the copper-containing waste slag, and ρ is the density of the copper-containing waste slag.

[0014] As a further improvement of the present invention, in step S1, the iron removal underflow and the neutralization overflow are mixed in a mass ratio of 1:5 to 15 for washing, and the obtained first filter press residue meets the general requirements of industrial solid waste and can be safely stored and disposed of.

[0015] As a further improvement of the present invention, in step S2, the method of adjusting the ORP value is: adding a sulfiding agent to react for 0.25~0.5h to adjust the ORP value to 0~200mv; the sulfiding agent is one of sodium sulfide, sodium hydrosulfide, and hydrogen sulfide gas.

[0016] As a further improvement of the present invention, in step S3, the pH is adjusted by adding a pH regulator and reacting for 0.8 to 1.2 hours to adjust the pH to 8.2 to 8.8; the pH regulator is lime or carbide slag.

[0017] As a further improvement of the present invention, the flocculants added in step S1, step S2 and step S3 are all non-ionic flocculants; the amount of the flocculant added in step S2 is 1-5 g / m 3 The amount of flocculant added in step S1 and step S3 is 1~15g / m 3 .

[0018] As a further improvement of the present invention, in step S1, 2% to 20% of the iron removal bottom flow is refluxed into the slurry adjustment reaction tank.

[0019] As a further improvement of the present invention, in step S2, 2% to 10% of the sulfidation underflow is refluxed into the sulfidation reaction tank.

[0020] As a further improvement of the present invention, in step S3, 70% to 90% of the neutralization bottom flow is refluxed into the neutralization reaction tank.

[0021] As a further improvement of the present invention, in step S1, before adding the copper-containing waste slag to the mine acidic water, the copper-containing waste slag is first crushed and screened, and then the crushed and screened copper-containing waste slag is added to the mine acidic water.

[0022] As a further improvement of the present invention, in step S1, the mine acidic water is acidic wastewater produced by non-ferrous metal mines under the action of air, water and microorganisms, and the pH value of the mine acidic water is 1-3.

[0023] The beneficial effects of the present invention are:

[0024] 1. The resource utilization method of copper-containing waste slag provided by the present invention adopts mine acidic water to treat waste with waste according to the pollution endowment characteristics of copper-containing waste slag. Through the combined treatment technology of physical and chemical methods, copper-containing waste slag is first added to the mine acidic water for slurry preparation, and then the iron removal underflow is washed with the neutralization overflow after flocculation and thickening treatment. After washing, the iron removal underflow is sequentially subjected to sulfidation treatment and neutralization treatment. The first filter press residue obtained after the washing treatment can meet the requirements of general industrial solid waste; the second filter press residue obtained after the sulfidation treatment can be sold as copper slag, thereby realizing efficient recovery and resource utilization of the valuable substance copper; at the same time, the third filter press residue obtained after the neutralization treatment can also meet the requirements of general industrial solid waste, realizing the harmlessness and resource utilization of the copper-containing waste slag; and the target heavy metals in the neutralization overflow and the third filter press liquid obtained after the neutralization treatment meet the emission standards, thereby realizing efficient treatment of high-copper acidic water.

[0025] 2. The method for resource utilization of copper-containing waste slag provided by the present invention can improve the recovery rate of valuable substance copper and the grade of the obtained copper slag by first subjecting the copper-containing waste slag to slurry treatment, and then subjecting the waste slag to harmless treatment, sulfidation treatment, and neutralization treatment after the slurry treatment; on this basis, the parameters such as the slurrying ratio, ORP value, pH value, reflux ratio, etc. are further regulated, and the copper-containing waste slag can be efficiently processed into resource-utilizable copper slag and harmless waste slag that meets the requirements of solid waste with a simple process, and at the same time, the mine acidic water can be treated into water bodies that meet the discharge standards.

[0026] 3. The method for resource utilization of copper-containing waste slag provided by the present invention has a simple process, safe and reliable operation, and uses common and inexpensive reagents. While rendering the copper-containing waste slag harmless and recycling it, it can also achieve deep purification of mine acidic water, with significant economic, environmental and social benefits, providing a new approach for the treatment of copper-containing waste slag and mine acidic water. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is a schematic diagram of the process flow of the method for resource utilization of copper-containing waste slag provided in Example 1. DETAILED DESCRIPTION

[0028] In order to make the objectives, technical solutions and advantages of the present invention more clear, the present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0029] It should also be noted here that, in order to avoid obscuring the present invention due to unnecessary details, only structures and / or processing steps closely related to the solutions of the present invention are shown in the drawings, while other details that are not closely related to the present invention are omitted.

[0030] In addition, it should be noted that the terms "comprises", "includes" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or apparatus that includes a series of elements includes not only those elements, but also includes other elements not explicitly listed, or also includes elements inherent to such process, method, article or apparatus.

[0031] The present invention provides a method for resource utilization of copper-containing waste slag, comprising the following steps:

[0032] S1. Adding copper-containing waste residue to acidic water from a mine, and fully stirring and slurrying in a slurry mixing tank to obtain copper-containing waste liquid; adding a flocculant to the copper-containing waste liquid, and obtaining a deironing underflow and a deironing overflow after solid-liquid separation in a deironing thickener; a portion of the deironing underflow is returned to the slurry mixing tank, and the other portion is mixed with the neutralization overflow in a predetermined mass ratio for washing, and after washing, a filter press dehydration operation is performed to obtain a first filter press residue and a first filter press liquid, wherein the first filter press residue meets the requirements of general industrial solid waste and can be safely stored and disposed of;

[0033] S2, inputting the first press filtrate and the iron removal overflow obtained in step S1 into a sulfidation reaction tank, adding a sulfiding agent to adjust the ORP value, and obtaining a sulfided copper-collecting turbid liquid; adding a flocculant to the sulfided copper-collecting turbid liquid, and obtaining a sulfided underflow and a sulfided overflow after solid-liquid separation in a sulfidation thickener; a portion of the sulfided underflow is refluxed into the sulfidation reaction tank, and the other portion is subjected to a press filter dehydration treatment to obtain a second press filter residue and a second press filter liquid; wherein the second press filter residue can be sold as copper slag;

[0034] S3. The sulfide overflow and the second filter press liquid obtained in step S2 are input into a neutralization reaction tank, and the pH value is adjusted to obtain a neutralized turbid liquid; a flocculant is added to the neutralized turbid liquid, and after solid-liquid separation by a neutralization thickener, a neutralization underflow and a neutralization overflow are obtained; a part of the neutralization underflow is returned to the neutralization reaction tank, and the other part is subjected to filter press dehydration treatment to obtain a third filter press residue and a third filter press liquid; wherein, the neutralization overflow and the third filter press liquid meet the emission standards, a part of the neutralization overflow is used to wash the iron removal underflow in step S1, and the remaining neutralization overflow can be discharged after being tested to meet the standards; the leaching toxicity and toxic substance content of the third filter press residue meet the requirements of general industrial solid waste, and can be stored in compliance as general industrial solid waste.

[0035] More specifically, in step S1, the copper-containing waste slag is first crushed and screened using a spiral feeding system, arch breaking equipment, ball milling equipment and other devices to obtain copper-containing waste slag with a particle size of less than 5 mm; then, the mine acidic water is injected into the slurry mixing tank, and the copper-containing waste slag after the crushing and screening treatment is quantitatively fed into the slurry mixing tank using the spiral feeding system, and is fully stirred for more than 1 hour to perform slurry mixing.

[0036] Among them, the mine acidic water is acidic wastewater produced by non-ferrous metal mines under the action of air, water and microorganisms, and the pH value of the mine acidic water is 1~3; the equipment material of the slurry mixing tank needs to be anti-corrosion material such as 316 L.

[0037] During the slurry adjustment treatment, the slurry adjustment ratio is preliminarily adjusted so that the mass concentration of the solid phase in the copper-containing waste liquid is between 10% and 40%. The slurry adjustment ratio is further adjusted according to the pH value of the liquid phase in the copper-containing waste liquid so that the pH value of the liquid phase in the copper-containing waste liquid is between 3.4 and 3.6.

[0038] Specifically, when the slurry adjustment ratio is further regulated according to the pH value of the liquid phase in the copper-containing waste slag liquid, the proportional relationship between the volume of the mine acidic water and the mass of the copper-containing waste slag is determined according to the following formula:

[0039]

[0040] Among them, α1 is the first correction factor, with a value range of 0.015~0.050, which is determined based on parameters such as the type, content, and density of the acidic and alkaline substances in the acidic water and neutralized slag; pH1 is the pH value of the mine acidic water, V is the volume of the mine acidic water, pH2 is the pH value of the copper-containing waste slag (i.e., the pH value of the solution obtained by mixing the copper-containing waste slag with pure water in a mass ratio of 1:1), m is the mass of the copper-containing waste slag, and ρ is the density of the copper-containing waste slag; pH1 and pH2 are both obtained by taking the average of the measured data of multiple pH online monitors installed in the reaction tank (each control detection point has no less than 3).

[0041] In step S2, the ORP value is adjusted by adding a sulfiding agent to a value between 0 and 200 mV to chemically precipitate heavy metal ions (primarily copper, etc.), with a reaction time of 0.25 to 0.5 hours. The sulfiding agent is selected from sodium sulfide, sodium bisulfide, or hydrogen sulfide gas. When a portion of the sulfidation underflow is returned to the sulfidation reaction tank, the reflux ratio is controlled to 2% to 10%, thereby maintaining the solid phase concentration in the sulfidation underflow at 10% to 20% during the circulation process, thereby reducing the processing pressure in the sulfidation underflow filter press section.

[0042] Among them, the ORP1 value of the first press filtrate before sulfidation, the flow rate Q1 of the first press filtrate before sulfidation, the ORP2 value of the sulfidation underflow returned to the sulfidation reaction tank, the reflux rate Q2 of the sulfidation underflow returned to the sulfidation reaction tank, the ORP3 value of the sulfidation copper-collecting turbid liquid after sulfidation, the flow rate Q3 of the sulfidation copper-collecting turbid liquid after sulfidation, the dosage Q4 of the sulfiding agent, and the ORP4 value of the sulfiding agent meet the following relationship:

[0043] Q4×ORP4=(ORP3×Q3-ORP1×Q1+ORP2×Q2)×α2

[0044] Among them, α2 is the second correction factor, with a value range of 0.008~0.035, which is determined according to the content and type of different substances in the acidic water. If the copper content in the acidic water is relatively high and the content of other base metals is relatively low, the second correction factor is smaller. ORP1, ORP2, and ORP3 are all obtained by taking the average of the measured data of multiple ORP online monitors set in the reaction tank (each control detection point is no less than 3). The ORP online monitor is set at a height of 0.5 times the tank depth or 50 cm below the liquid surface. The ORP4 value of the sulfiding agent is related to the type and concentration of the sulfiding agent. A 20% sodium sulfide solution is preferred. Under this condition, the ORP4 value is -480mV.

[0045] In step S3, the pH is adjusted by adding a pH adjuster to a range of 8.2-8.8, converting most heavy metals (especially manganese) and other harmful substances into precipitates. The reaction time is 0.8-1.2 hours. The pH adjuster is lime or carbide slag. When a portion of the neutralization underflow is returned to the neutralization reaction tank, the reflux ratio (the ratio of the mass of the neutralization underflow returned to the neutralization reaction tank to the mass of the sulfide overflow input to the neutralization reaction tank) is controlled to 1:4-5. This ensures that the mass concentration of the solid phase in the neutralization underflow is controlled at 15%-30% during the circulation process, thereby reducing the processing pressure in subsequent stages.

[0046] The flocculants added in steps S1, S2 and S3 are all nonionic flocculants; more preferably, the amount of flocculant added in step S2 is 1-5 g / m 3 The amount of flocculant added in steps S1 and S3 is 1-15 g / m 3 .

[0047] The method for resource utilization of copper-containing waste slag provided by the present invention is described below with reference to specific embodiments.

[0048] Example 1

[0049] This embodiment provides a method for resource utilization of copper-containing waste slag, which is targeted at copper-containing waste slag with a copper grade of about 1.5% and a pH value of mine acidic water of about 2.4. The process flow diagram is shown in FIG. Figure 1 As shown in the figure (the dotted line in the figure represents the bottom flow in a sludge state), the specific steps include the following.

[0050] S1. Slurry preparation of copper-containing waste slag

[0051] A certain amount of mine acidic water is injected into the slurry mixing tank, and then copper-containing waste slag is quantitatively fed into the slurry mixing tank using a spiral feeding system, so that the mass concentration of the solid phase in the obtained copper-containing waste slag liquid is between 10% and 40%, and the mixture is fully stirred for 2 hours. The end point of the mass concentration control is that the pH value of the liquid phase in the copper-containing waste slag liquid is about 3.5. The proportional relationship between the volume of the mine acidic water and the mass of the copper-containing waste slag is determined according to the following formula:

[0052]

[0053] Wherein, α1 is the first correction factor, and its value range is 0.015~0.050. In this embodiment, it is determined to be 0.024 according to the properties of acidic water and neutralized slag; pH1 is the pH value of the mine acidic water. In this embodiment, four pH online monitors are set in the acidic water buffer tank, and the average value is used as the pH1 of the mine acidic water, which is measured to be approximately 2.45; pH2 is the pH value of the copper-containing waste slag. In this embodiment, three pH online monitors are set in the copper-containing waste slag pH monitoring tank (copper-containing waste slag and pure water are mixed in a ratio of 1:1), and the average value is used as the pH2 of the copper-containing waste slag, which is measured to be approximately 9.10; ρ is the density of the copper-containing waste slag, which is measured to be 1.5 t / m 3 Substituting the corresponding data into the above formula can determine the proportional relationship between the volume V of the mine acidic water and the mass m of the copper-containing waste slag, so that the pH value of the obtained copper-containing waste slag liquid is around 3.5.

[0054] Then the copper-containing waste liquid is fed into the iron removal flocculation reaction tank and the 3 A non-ionic flocculant is added to the copper-containing waste slag liquid in an amount of 1:1, and then the liquid is fed into a deironing sedimentation tank, and is thickened by a deironing thickener to obtain a deironing overflow and a deironing underflow in a sludge state; 10% of the deironing underflow is returned to the slurry mixing tank, and the remaining deironing underflow enters the iron slag harmless treatment process, and is mixed with the neutralization overflow obtained in the subsequent step S3 at a solid-liquid mass ratio of 1:6 and then washed, and after washing, a filter press dehydration operation is performed to obtain a first filter press residue and a first filter press liquid; the first filter press residue meets the requirements of general industrial solid waste and can be safely stored and disposed of; the first filter press liquid and the deironing overflow enter the sulfidation treatment section.

[0055] S2, sulfide copper

[0056] The first press filtrate obtained in step S1 and the iron removal overflow are input into the sulfidation reaction tank, and a 20% sodium hydrosulfide solution is used as a sulfiding agent. The sulfiding agent enters the sulfidation reaction tank through the sulfidation mud mixing tank, and is fully reacted for 0.5 hours. The ORP value is adjusted to 0mv to chemically precipitate heavy metal ions (mainly copper, etc.) to obtain a sulfidation copper-collecting turbid liquid. The sulfidation copper-collecting turbid liquid is input into the sulfidation flocculation reaction tank and the sulfidation flocculation reaction tank is heated at 5g / m 3A non-ionic flocculant is added to the sulfide copper recovery turbid liquid in an amount of 1000mg / L, and then the liquid is fed into a sulfide sedimentation tank. Solid-liquid separation is performed in a sulfide thickener to obtain a sulfide overflow and a sulfide underflow in a sludge state. A portion of the sulfide underflow is refluxed to the sulfide reaction tank through a sulfide slurry mixing tank, and the reflux ratio is controlled to be 10%. The other portion is subjected to filter press dehydration treatment to obtain a second filter press residue and a second filter press liquid. The second filter press residue can be sold as copper slag (its copper grade is measured to be 35%, and the copper recovery rate is 99.3%). The second filter press liquid and the sulfide overflow enter a neutralization section.

[0057] Specifically, when adjusting the ORP value, the ORP1 value of the first press filtrate before sulfidation, the flow rate Q1 of the first press filtrate before sulfidation, the ORP2 value of the sulfidation underflow returned to the sulfidation reaction tank, the reflux rate Q2 of the sulfidation underflow returned to the sulfidation reaction tank, the ORP3 value of the sulfidation copper-collecting turbid liquid after sulfidation, the flow rate Q3 of the sulfidation copper-collecting turbid liquid after sulfidation, the dosage Q4 of the sulfidizing agent, and the ORP4 value of the sulfiding agent meet the following relationship:

[0058] Q4×ORP4=(ORP3×Q3-ORP1×Q1+ORP2×Q2)×α2

[0059] Wherein, α2 is the second correction factor, and its value range is 0.008~0.035. In this embodiment, it is determined to be 0.012 according to the properties of mine acidic water. In this embodiment, an ORP online monitor is set in the filter press buffer tank before the sulfidation reaction, and a flow meter is set after the first filter press delivery pump. The measured ORP1 value is about 600 mv, and Q1 is about 330 m 3 / h, an ORP online monitor and flow meter were set on the sulfide bottom flow return pipeline, and the measured ORP2 value was about 50 mv and Q2 was about 30 m 3 / h, an ORP online monitor is set in the sulfidation reaction tank to control the ORP3 value at 0 mv and Q3 at about 360 m 3 / h, the ORP4 value of the sulfiding agent 20% sodium sulfide solution is -480 mV. Substituting the corresponding data into the above formula can determine the dosage of the sulfiding agent Q4 so that the ORP3 value of the sulfided copper sulfide turbid solution after sulfidation is controlled at 0 mV.

[0060] S3, neutralization

[0061] The sulfide overflow obtained in step S2 and the second press filtrate are fed into the neutralization reaction tank, and 20% lime milk solution is added to the neutralization reaction tank through the neutralization slurry mixing tank, and the pH value is adjusted to above 8.5 to chemically precipitate heavy metal ions (mainly iron, arsenic, zinc, lead, manganese, nickel, etc.) so that they can be removed in the form of solid heavy metal precipitates. After reacting for 1 hour, a neutralized turbid liquid is obtained. The neutralized turbid liquid is fed into the neutralization sedimentation tank and the precipitate is heated at 12 g / m 3 A nonionic flocculant is added to the neutralized turbid liquid in an amount of 1000 nm. Solid-liquid separation is then performed in a neutralization thickener to produce a neutralization overflow and a sludge-like neutralization underflow. A portion of the neutralization underflow is returned to the neutralization reaction tank via a neutralization slurry mixing tank, with the reflux ratio controlled at 80%. The remaining portion is subjected to filter press dehydration to produce a third filter press residue and a third filter press liquid. The target heavy metals in the neutralization overflow and the third filter press liquid meet the direct emission limit values specified in the Class I emission standard of the Integrated Wastewater Discharge Standard (GB 8978-1996) and the Copper, Cobalt, and Nickel Industrial Pollutant Discharge Standard (GB 25467-2010). A portion of the neutralization overflow is directly discharged, while the remaining portion is fed into the iron slag harmless treatment process for treating the iron removal underflow in step S1. The third filter press residue meets the requirements for general industrial solid waste and can be stored in compliance with regulations as general industrial solid waste.

[0062] The water quality of the inlet and outlet water of this embodiment was tested, and the results are shown in Table 1:

[0063] Table 1 Acidic water inlet and outlet water quality

[0064]

[0065] Note: pH is dimensionless. The unit of other indicators in the table is "mg / L". Indicators such as pH, Cu, Pb, Zn, Cd, Cr, As, Ni, Mn, COD, and ammonia nitrogen adopt the requirements of the first-level standard of the "Integrated Wastewater Discharge Standard" (GB 8979-1996).

[0066] Application Example Referring to the relevant requirements of the "General Standard for Identification of Hazardous Wastes" (GB 5085.7-2019), the first filter press residue obtained after the harmless treatment in step S1 is pre-identified for solid waste properties. The specific method is as follows.

[0067] 1) Flammability analysis

[0068] Pyrophoric substances are items that readily undergo oxidation reactions in air, releasing heat and spontaneously combusting. As the definition indicates, the primary characteristic of these items is their ability to spontaneously generate heat and combust in air. In this project, the primary filter press residue consisted primarily of ferric hydroxide and metal precipitates. Preliminary analysis indicates that the residue is not flammable.

[0069] 2) Reactivity analysis

[0070] The first filter press residue produced by the normal process of this project is stable and non-explosive at room temperature and pressure. It does not undergo drastic changes in the absence of detonation. At standard temperature and pressure (25°C, 101.3 kPa), it does not undergo detonation or explosive decomposition reactions, and preliminary analysis indicates that it is non-explosive. The first filter press residue produced by the normal process of this project does not produce flammable gases or trace amounts of toxic gases when in contact with water. When mixed with water, it does not produce toxic gases, vapors, or fumes that are harmful to human health or the environment. Under acidic conditions, it does not decompose to produce hydrogen cyanide or H2S gas. The first filter press residue is not considered a waste oxidant or organic peroxide. Therefore, preliminary analysis indicates that it is non-reactive.

[0071] 3) Initial screening analysis of acute toxicity

[0072] The main components of the first filter press residue produced by the normal process of this project are iron hydroxide and metal precipitates. Preliminary analysis shows that the first filter press residue does not have acute toxicity.

[0073] 4) Corrosion analysis

[0074] According to the "Identification of Corrosiveness of Hazardous Waste Identification Standard" (GB 5085.1-2007), the leachate of the first filter press residue was prepared. After analysis and testing, the pH value of the leachate of the first filter press residue was 3.25, which did not meet the conditions of pH ≥ 12.5 or ≤ 2.0. Preliminary analysis showed that the first filter press residue was not corrosive.

[0075] 5) Leaching toxicity analysis

[0076] The toxicity leaching test of the first filter press residue was carried out in accordance with the requirements of "Solid Waste Leaching Toxicity Leaching Method Sulfuric Acid and Nitric Acid Method" (HJ / T 299-2007). The specific results are shown in Table 2.

[0077] Table 2 Results of leaching toxicity analysis of the first filter press residue

[0078]

[0079] Note: The unit of Hg in the table is μg / L, and the units of other indicators are mg / L. “L” means below the detection limit.

[0080] From the results in Table 2, it can be seen that, by comparing with the “Identification Standard for Hazardous Wastes - Leaching Toxicity Identification” (GB 5085.3-2007), it is preliminarily determined that the first filter press residue is general industrial solid waste.

[0081] 6) Toxic substance content

[0082] The components of the first filter press residue were analyzed in accordance with the requirements of the "Hazardous Waste Identification Standard - Identification of Toxic Substance Content" (GB 5085.6-2007). The specific results are shown in Table 3.

[0083] Table 3 Analysis results of the first filter press residue components

[0084]

[0085] Note: The indicator unit in the table is mg / kg, and “L” means below the detection limit.

[0086] The first filter press residue is mainly composed of iron hydroxide and metal hydroxide precipitate. By comparing with the "Identification Standard of Hazardous Waste - Identification of Toxic Substance Content" (GB 5085.6-2007), it is preliminarily judged that the toxic substances that may exist in the first filter press residue are "arsenic acid and its salts" and "elemental manganese".

[0087] Table 4 Analysis results of harmful substances in the first filter press residue

[0088]

[0089] According to Table 4, the toxic substance content of the first filter press residue is lower than the hazardous waste standard limit, and it is preliminarily judged that it meets the general industrial solid waste standard requirements.

[0090] Application Example Referring to the relevant requirements of the "General Standard for Identification of Hazardous Wastes" (GB 5085.7-2019), the solid waste properties of the third filter press residue obtained after the neutralization in step S3 are pre-identified. The specific method is as follows.

[0091] 1) Flammability analysis

[0092] Pyrophoric substances are items that readily undergo oxidation reactions in air, releasing heat and spontaneously combusting. As the definition indicates, the primary characteristic of these items is their ability to spontaneously generate heat and combust in air. In this project, the third filter press residue primarily consists of calcium sulfate and metal precipitates. Preliminary analysis indicates that the third filter press residue is not flammable.

[0093] 2) Reactivity analysis

[0094] The third filter press residue produced by the normal process of this project is stable and non-explosive at room temperature and pressure. It does not undergo drastic changes in the absence of detonation. At standard temperature and pressure (25°C, 101.3 kPa), it does not undergo detonation or explosive decomposition reactions, and preliminary analysis indicates that it is non-explosive. The third filter press residue produced by the normal process of this project does not produce flammable gases or trace amounts of toxic gases when in contact with water. When mixed with water, it does not produce toxic gases, vapors, or fumes that are harmful to human health or the environment. Under acidic conditions, it does not decompose to produce hydrogen cyanide or H2S gas. Third filter press residue is not considered a waste oxidant or organic peroxide. Therefore, preliminary analysis indicates that it is non-reactive.

[0095] 3) Initial screening analysis of acute toxicity

[0096] The main components of the third filter press residue produced by the normal process of this project are calcium sulfate and metal precipitates, without any acute toxic substances. Preliminary analysis shows that the third filter press residue does not have acute toxicity.

[0097] 4) Corrosion analysis

[0098] According to the "Identification of Corrosiveness of Hazardous Waste Identification Standard" (GB 5085.1-2007), the leachate of the third filter press residue was prepared. After analysis and testing, the pH value of the leachate of the third filter press residue was 7.98, which did not meet the conditions of pH ≥ 12.5 or ≤ 2.0. Preliminary analysis showed that the third filter press residue was not corrosive.

[0099] 5) Leaching toxicity analysis

[0100] The toxicity leaching test of the third filter press residue was carried out in accordance with the requirements of "Solid Waste Leaching Toxicity Leaching Method Sulfuric Acid and Nitric Acid Method" (HJ / T 299-2007). The specific results are shown in Table 5.

[0101] Table 5 Leaching toxicity analysis results of the third filter press residue

[0102]

[0103] Note: The unit of indicators in the table is μg / L, and “L” means below the detection limit.

[0104] From the results in Table 5, we can see that, by comparing with the “Identification Standard for Hazardous Wastes - Leaching Toxicity Identification” (GB 5085.3-2007), it is preliminarily determined that the third filter press residue is general industrial solid waste.

[0105] 6) Toxic substance content

[0106] The third filter press residue was analyzed for components according to the "Hazardous Waste Identification Standard - Toxic Substance Content" (GB 5085.6-2007). The third filter press residue was primarily composed of calcium sulfate and metal hydroxide precipitate. By comparing this with the "Hazardous Waste Identification Standard - Toxic Substance Content" (GB 5085.6-2007), the potential toxic substances present in the third filter press residue were initially determined to include "arsenic acid and its salts" and "elemental manganese."

[0107] Table 6 Analysis results of harmful substances in the third filter press residue

[0108]

[0109] According to Table 6, the toxic substance content of the third filter press residue is lower than the standard limit for hazardous waste, and it is preliminarily judged that it meets the standard requirements for general industrial solid waste.

[0110] As can be seen from the table above, after the treatment method for high-copper acidic water treatment and slag harmlessness provided in this embodiment is used, the effluent water quality and the generated solid waste meet the corresponding requirements. And the overall treatment process can treat 500m3 of high-copper acidic water. 3 / h, and the iron slag output after harmless treatment is about 18t / d, which realizes the efficient treatment of high-copper acidic water and achieves the effect of harmless slag production.

[0111] Comparative Examples 1-3

[0112] Comparative Examples 1 to 3 respectively provide a method for resource utilization of copper-containing waste slag. Compared with Example 1, the difference is that the pH value of the liquid phase in the copper-containing waste slag solution after adjustment in step S1, the mass ratio of the iron removal underflow and the neutralization overflow, and the pH value in step S3 are respectively changed. The corresponding parameters corresponding to each comparative example are shown in Table 7. The remaining steps and parameters are consistent with Example 1 and are not repeated here.

[0113] Table 7 Process parameters in Comparative Examples 1 to 3

[0114]

[0115] After treating the high-copper acidic water according to the methods provided in Comparative Examples 1 to 3 above, the copper recovery rate, effluent water quality and generated solid waste were tested, and the results are shown in Table 8.

[0116] Table 8 Test results in Comparative Examples 1 to 3

[0117]

[0118] As can be seen from Table 8, controlling the pH value of step S1 above 3.6 directly affects the copper recovery rate. Failure to wash the underflow of iron removal in step S1 or insufficient washing ratio will directly affect the solid waste properties of the first filter press residue, making it unable to meet the requirements of general industrial solid waste and affecting the copper recovery rate. If the pH value of step S3 cannot be controlled at around 8.5, it is impossible to ensure that various pollutants in the acidic water are effectively treated to meet the standards, especially Mn, whose concentration after treatment is still as high as 4.67 mg / L, far exceeding the limit of 2 mg / L required by the standard.

[0119] In summary, the present invention provides a method for resource utilization of copper-containing waste slag. The method comprises the following steps: adding copper-containing waste slag to acidic water of a mine, fully stirring and slurrying to obtain copper-containing waste slag liquid; adding a flocculant to the copper-containing waste slag liquid, and performing solid-liquid separation in an iron removal thickener to obtain an iron removal underflow and an iron removal overflow; mixing the iron removal underflow and a neutralization overflow in a predetermined mass ratio and washing them, wherein the mass ratio is controlled between 1:5 and 15; performing a filter press dehydration operation after washing, and generating a first filter press residue that meets the requirements of general industrial solid waste and can be safely stored and disposed of; then, inputting the first filter press liquid and the iron removal overflow obtained after the filter press dehydration treatment of the copper-containing waste slag solution into a sulfidation reaction tank, adding a sulfiding agent to adjust the ORP value, and performing a sulfidation copper collection treatment to obtain a sulfidation overflow, a second filter press liquid, and a second filter press residue that can be collected as copper slag; then, inputting the sulfidation overflow and the second filter press liquid into a neutralization reaction tank and performing a neutralization treatment to finally obtain a neutralization overflow and a third filter press liquid that meet the emission standards, and a third filter press residue that meets the requirements of general industrial solid waste. Through the above-mentioned method, the present invention can utilize mine acidic water to treat copper-containing waste slag with waste treatment. While rendering the copper-containing waste slag harmless and recycling it as a resource, it can also achieve deep purification of mine acidic water, which has significant economic, environmental and social benefits.

[0120] The above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention.

Claims

1. A method for resource utilization of copper-containing waste slag, characterized in that: The steps include: S1. Add copper-containing waste slag to mine acidic water, fully stir and prepare the slurry in a slurry mixing tank to obtain copper-containing waste slag liquid; add a flocculant to the copper-containing waste slag liquid, and obtain a deironing underflow and a deironing overflow after solid-liquid separation in a deironing thickener; mix at least a portion of the deironing underflow and the neutralization overflow in a predetermined mass ratio for washing, and perform a filter press dehydration operation after washing to obtain a first filter press residue and a first filter press liquid; the pH value of the liquid phase in the copper-containing waste slag liquid is 3.4-3.6; the mine acidic water is acidic wastewater generated by non-ferrous metal mines under the action of air, water and microorganisms, and the pH value of the mine acidic water is 1-3; the proportional relationship between the volume of the mine acidic water and the mass of the copper-containing waste slag is determined according to the following formula: Wherein, α1 is the first correction factor, and its value range is 0.015~0.050; pH1 is the pH value of the mine acidic water, V is the volume of the mine acidic water, pH2 is the pH value of the copper-containing waste slag, m is the mass of the copper-containing waste slag, and ρ is the density of the copper-containing waste slag; The iron removal underflow and the neutralization overflow are mixed in a mass ratio of 1:5-15 for washing, and the obtained first filter press residue meets the requirements of general industrial solid waste and can be safely stored and disposed of; S2, inputting the iron removal overflow obtained in step S1 and the first press filtrate into a sulfidation reaction tank, adding a sulfiding agent to adjust the ORP value, and obtaining a sulfided copper-collecting turbid liquid; adding a flocculant to the sulfided copper-collecting turbid liquid, and obtaining a sulfided underflow and a sulfided overflow after solid-liquid separation in a sulfidation thickener; and subjecting at least a portion of the sulfided underflow to a filter press dehydration treatment to obtain a second filter press residue and a second filter press liquid; S3. Inputting the sulfide overflow and the second press filtrate obtained in step S2 into a neutralization reaction tank, adding a pH adjuster, and adjusting the pH value to 8.2-8.8 to obtain a neutralized turbid liquid; the pH adjuster is lime or carbide slag; adding a flocculant to the neutralized turbid liquid, and obtaining a neutralization underflow and a neutralization overflow after solid-liquid separation in a neutralization thickener; and subjecting at least a portion of the neutralization underflow to a filter press dehydration treatment to obtain a third filter press residue and a third filter press liquid.

2. The method for resource utilization of copper-containing waste slag according to claim 1, characterized in that: In step S1, the mass concentration of the solid phase in the copper-containing waste slag liquid is 10% to 40%.

3. The method for resource utilization of copper-containing waste slag according to claim 1, characterized in that: In step S1, the sufficient stirring time is more than 1 hour.

4. The method for resource utilization of copper-containing waste slag according to claim 1, characterized in that: In step S2, the ORP value is adjusted by adding a sulfiding agent and reacting for 0.25 to 0.5 hours to adjust the ORP value to 0 to 200 mv; the sulfiding agent is one of sodium sulfide, sodium hydrosulfide, and hydrogen sulfide gas.

5. The method for resource utilization of copper-containing waste slag according to claim 1, characterized in that: In step S3, the pH is adjusted by adding a pH adjuster and reacting for 0.8 to 1.2 hours.

6. The method for resource utilization of copper-containing waste slag according to claim 1, characterized in that: The flocculants added in step S1, step S2 and step S3 are all non-ionic flocculants; the amount of flocculant added in step S2 is 1-5 g / m 3 The amount of flocculant added in step S1 and step S3 is 1~15g / m 3 .

7. The method for resource utilization of copper-containing waste slag according to claim 1, characterized in that: In step S1, 2% to 20% of the iron removal bottom flow is returned to the slurry mixing tank; in step S2, 2% to 10% of the sulfidation bottom flow is returned to the sulfidation reaction tank; in step S3, 70% to 90% of the neutralization bottom flow is returned to the neutralization reaction tank.

8. The method for resource utilization of copper-containing waste slag according to claim 1, characterized in that: In step S1, before adding the copper-containing waste slag into the mine acidic water, the copper-containing waste slag is first crushed and screened, and then the copper-containing waste slag after the crushing and screening process is added into the mine acidic water.

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