Comprehensive treatment method for gold-containing copper smelting wastewater

Abstract

The present application provides a comprehensive treatment method for gold-containing copper smelting wastewater, belonging to the technical field of wastewater treatment. The method includes: adding reduced iron powder to the gold-containing copper smelting wastewater, and obtaining a turbid liquid after iron powder replacement through sufficient reaction; adding a first pH regulator to the turbid liquid after iron powder replacement, adjusting the pH value and then adding an oxidant, and obtaining a turbid liquid after iron removal through sufficient reaction; adding a flocculant to the turbid liquid after iron removal, and after sufficient flocculation, obtaining an underflow after iron removal and an overflow after iron removal through solid-liquid separation; performing pressure filtration and dehydration treatment on the underflow after iron removal to obtain gold-copper slag and filtrate after pressure filtration; mixing the overflow after iron removal and the filtrate after pressure filtration, and adding a second pH regulator, adjusting the pH value and then reacting sufficiently to obtain a neutralized turbid liquid. Through the above method, while effectively recovering valuable substances, the present application avoids the impact of harmful metal ions in the wastewater on the production system or the ecological environment, and no hazardous waste is generated throughout the process, achieving the unity of environmental benefits and economic benefits.

Description

Technical Field

[0001] The present invention relates to the technical field of wastewater treatment, and particularly relates to a comprehensive treatment method for gold-containing copper smelting wastewater. Background Art

[0002] Cyanidation gold extraction has the advantages of simple process and high gold recovery rate. It is the mainstream wet gold leaching process in the global gold industry at present and for some time to come. It mainly includes processes such as cyanidation leaching, carbon-in-pulp gold extraction, acid washing of gold-loaded carbon, electrolytic recovery of gold mud, and gold mud smelting. Among them, during the processes of acid washing of gold-loaded carbon and gold mud smelting, a certain amount of smelting wastewater is usually generated. These smelting wastewaters often contain substances such as gold, silver, copper, lead, and arsenic, including both valuable substances and harmful substances. If the smelting wastewater cannot be effectively treated, not only will valuable substances be lost, but the presence of harmful substances will also affect the production system or the ecological environment.

[0003] The traditional treatment method for smelting wastewater is usually to use activated carbon for adsorption, and then recover valuable substances through methods such as acid washing desorption and electrolysis. However, a large amount of acidic wastewater is still generated during this process, and harmful substances such as lead and arsenic cannot be effectively treated. If it is discharged as waste, it will affect the environment. If it is recycled to the gold production system for circulation, it will have a negative impact on the process indicators of gold production. Therefore, how to eliminate the enrichment of other harmful substances in the production system while realizing the recovery of valuable substances is a current research hotspot.

[0004] In the prior art, the sulfide method is mainly used to recover the required substances in smelting wastewater. For example, the patent with the publication number CN113816534A provides a process for deep impurity removal and resource recovery of gold smelting wastewater. By using sulfide agents, valuable substances such as zinc and copper in the wastewater are recovered in the form of sulfide precipitates at different pH values, and other impurity ions are removed through neutralization reactions. However, the neutralization slag obtained after the neutralization reaction belongs to general solid waste, and the neutralized liquid still needs to be aerated. It cannot be directly recycled, and the disposal process is complex and costly. The patent with the publication number CN103145267A provides a method for recovering copper sulfide and iron hydroxide in acidic gold copper mine wastewater by the sulfide method. By adding alkali, iron hydroxide is flocculated and precipitated, then sodium sulfide is added to recover copper sulfide, and finally limestone is added to recover gypsum. This way of stepwise recovering different products not only has a complex process, but in fact, each product will be mixed with more harmful substances and needs to be further processed before it can be sold as valuable substances. Moreover, different recovery methods are usually required for smelting wastewaters with different compositions. The above methods are mainly applicable to the recovery of copper and are difficult to effectively recover gold.

[0005] In view of this, it is necessary to design an improved comprehensive treatment method for gold-containing copper smelting wastewater to solve the above problems. Summary of the Invention

[0006] In view of the technical problems existing in the background art, the present application provides a comprehensive treatment method for gold-containing copper smelting wastewater. By sequentially performing displacement treatment, iron removal treatment, and neutralization treatment on the gold-containing copper smelting wastewater, and precisely controlling parameters such as pH value and chemical agent dosage during the treatment process, while effectively recovering valuable substances such as gold, silver, and copper, it avoids the impact of harmful metal ions in the wastewater on the production system or the ecological environment, and no hazardous waste is generated during the treatment process, achieving the unity of environmental benefits and economic benefits.

[0007] The embodiment of the present application provides a comprehensive treatment method for gold-containing copper smelting wastewater, including the following steps:

[0008] S1. Add a predetermined amount of reduced iron powder to the gold-containing copper smelting wastewater, and obtain a turbid liquid after iron powder displacement through sufficient reaction;

[0009] The dosage of the reduced iron powder satisfies the following conditions:

[0010] m 铁 =α×0.88×(m 铜 +m 金 +m 银 )÷1000

[0011] Wherein, m 铜 、m 金 and m 银 are respectively the mass concentrations of copper ions, gold ions, and silver ions in the gold-containing copper smelting wastewater, with the unit of mg / L; m 铁 is the dosage of reduced iron powder added to the gold-containing copper smelting wastewater per unit volume, with the unit of g / L; α is the reaction coefficient, and the value range is 1.0~1.1;

[0012] S2. Add a first pH regulator to the turbid liquid after iron powder displacement, adjust the pH value, then add an oxidant, and obtain a turbid liquid after iron removal through sufficient reaction; add a flocculant to the turbid liquid after iron removal, and after sufficient flocculation, perform solid-liquid separation to obtain an iron removal underflow and an iron removal overflow; perform pressure filtration and dehydration treatment on the iron removal underflow to obtain gold-copper slag and filtrate after pressure filtration;

[0013] S3. Mix the iron removal overflow and the filtrate after pressure filtration, add a second pH regulator, adjust the pH value, and react sufficiently to obtain a neutralization turbid liquid.

[0014] In some embodiments, in step S1, when the pH of the gold-containing copper smelting wastewater is ≤0 and the total mass concentration of lead ions and arsenic ions in the gold-containing copper smelting wastewater is greater than 200 mg / L, the value range of α is 1.05 - 1.10; otherwise, the value range of α is 1.0 - 1.04.

[0015] In some embodiments, in step S1, the reaction time is 0.5 - 1 h.

[0016] In some embodiments, in step S2, the first pH regulator is used to adjust the pH value of the iron powder replacement turbid liquid to 3.7 - 5.0; the first pH regulator is one or more of lime, sodium hydroxide, and sodium bicarbonate.

[0017] In some embodiments, in step S2, the oxidant is hydrogen peroxide or oxygen; when the oxidant is hydrogen peroxide, the dosage of hydrogen peroxide is more than 0.3 times the dosage of the reduced iron powder; when the oxidant is oxygen, the volume ratio of oxygen added to the volume of the gold-copper smelting wastewater is 0.6 - 1:1.

[0018] In some embodiments, in step S2, the reaction time after adding the oxidant is 1 - 2 h.

[0019] In some embodiments, in step S2, the flocculant is a non-ionic flocculant, and the dosage is 1 - 5 g / m 3 。

[0020] In some embodiments, in step S2, after solid-liquid separation to obtain the iron-removed underflow and the iron-removed overflow, a part of the iron-removed underflow is refluxed to step S1, and the remaining iron-removed underflow is subjected to the pressure filtration and dehydration treatment; the reflux ratio of the iron-removed underflow is 5% - 25%.

[0021] In some embodiments, in step S3, the second pH regulator is used to adjust the pH value to 7.0 - 7.9, and the second pH regulator is lime or carbide slag.

[0022] In some embodiments, in step S3, the reaction time after adjusting the pH value is 0.5 - 1.5 h.

[0023] The beneficial effects of this application are:

[0024] The comprehensive treatment method for gold-containing copper smelting wastewater provided by this application can simply and efficiently recover valuable substances in the gold-containing copper smelting wastewater by sequentially performing displacement treatment, iron removal treatment, and neutralization treatment on the gold-containing copper smelting wastewater, directly performing subsequent iron removal treatment without flocculation after the displacement reaction, and further regulating the dosage of reduction iron powder in the displacement treatment process, the pH value during iron removal treatment, the dosage of oxidant, and the pH value of neutralization treatment. The final products obtained are only gold-copper slag and neutralization turbid liquid. Among them, the gold-copper slag has a high content of gold and copper, can meet the requirements of gold concentrate and copper concentrate products, and has less content of other harmful impurities, and can be directly sold as high-value substances; the content of harmful impurities in the liquid phase of the neutralization turbid liquid is very small, and the main component of the solid phase is calcium sulfate with a low iron content, making the neutralization turbid liquid meet the recovery requirements of the cyanidation gold extraction process, and can be directly reused in the cyanidation leaching process in the cyanidation leaching production process without solid-liquid separation, and does not affect the process indicators. Based on the comprehensive treatment method for gold-containing copper smelting wastewater provided by this application, while effectively recovering valuable substances such as gold, silver, and copper, it avoids the impact of harmful metal ions in the wastewater on the production system or the ecological environment, and no hazardous waste is generated during the entire treatment process, reducing the environmental risk of the storage of waste residues in the conventional water treatment process, and achieving the unity of economic benefits and environmental benefits. Brief Description of the Drawings

[0025] In order to more clearly illustrate the technical solutions of this application, the drawings used in this application will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0026] Figure 1 It is a schematic process flow diagram of the comprehensive treatment method for gold-containing copper smelting wastewater provided in Embodiment 1 of this application. Detailed Embodiments

[0027] The embodiments of the technical solutions of this application will be described in detail below with reference to the drawings. The following embodiments are only used to more clearly illustrate the technical solutions of this application, so they are only examples and cannot be used to limit the protection scope of this application.

[0028] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which this application belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" and any variations thereof in the specification and claims of this application and the above description of the drawings are intended to cover non-exclusive inclusion.

[0029] In the description of the embodiments of the present application, technical terms such as "first" and "second" are only used to distinguish different objects, and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity, specific order or primary-secondary relationship of the indicated technical features.

[0030] Reference to "embodiment" herein means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment of the present application. The phrase appears in various places in the specification and does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0031] For gold-containing copper smelting wastewater, conventional treatment methods not only have complex processes, but also it is difficult to effectively utilize all treatment products. Usually, some slag materials or waste liquids with high harmful substance content will be produced, which will affect the production system or the ecological environment.

[0032] To solve the above problems, the present application provides a comprehensive treatment method for gold-containing copper smelting wastewater. By sequentially performing displacement treatment, iron removal treatment, and neutralization treatment on the gold-containing copper smelting wastewater, and precisely controlling parameters such as the pH value and chemical agent dosage during the treatment process, while effectively recovering valuable substances such as gold, silver, and copper, it avoids the impact of harmful metal ions in the wastewater on the production system or the ecological environment, and no hazardous waste is generated during the treatment process, achieving the unity of environmental benefits and economic benefits.

[0033] Specifically, the embodiments of the present application provide a comprehensive treatment method for gold-containing copper smelting wastewater, including the following steps:

[0034] S1. Add a predetermined amount of reducing iron powder to the gold-containing copper smelting wastewater, and obtain a turbid liquid after full reaction;

[0035] The dosage of the reducing iron powder satisfies the following conditions:

[0036] m 铁 =α×0.88×(m 铜 +m 金 +m 银 )÷1000

[0037] Wherein, m 铜 , m 金 and m 银 are respectively the mass concentrations of copper ions, gold ions, and silver ions in the gold-containing copper smelting wastewater, with the unit of mg / L; m 铁 is the dosage of reducing iron powder per unit volume of the gold-containing copper smelting wastewater, with the unit of g / L; α is the reaction coefficient, and its value range is 1.0 - 1.1;

[0038] S2. Add a first pH regulator to the iron powder displacement turbid liquid, adjust the pH value, then add an oxidant, and obtain an iron-removed turbid liquid after sufficient reaction; add a flocculant to the iron-removed turbid liquid, after sufficient flocculation, perform solid-liquid separation to obtain an iron-removed underflow and an iron-removed overflow; perform pressure filtration and dehydration treatment on the iron-removed underflow to obtain a gold-copper slag and a filtrate.

[0039] S3. Mix the iron-removed overflow and the filtrate, add a second pH regulator, adjust the pH value, and react sufficiently to obtain a neutralized turbid liquid.

[0040] In the technical solution of the embodiment of the present application, by adding reduced iron powder to displace copper ions, gold ions, and silver ions in the gold-copper smelting wastewater, the valuable metal ions in the gold-copper smelting wastewater can be converted into corresponding metal simple substances, realizing the recovery of valuable metals in the wastewater. On this basis, the present application does not perform flocculation and solid-liquid separation on the iron powder displacement turbid liquid obtained after displacement in the conventional manner, but sends the wastewater after displacement treatment and the metal simple substances generated after the displacement reaction into the subsequent iron removal process together. By operating in this way, instead of collecting iron slag with high iron, lead, and arsenic contents that need to be treated as hazardous waste after iron removal treatment, a gold-copper slag with high value is collected. The gold grade in the gold-copper slag can reach more than 5%, and the copper grade can reach more than 20%. It also contains iron hydroxide precipitation and a small amount of lead and arsenic precipitates, effectively reducing the concentration of harmful metal ions in the wastewater, and the small amount of lead and arsenic does not affect the sale of the gold-copper slag with high gold and copper contents as high-value gold concentrate and copper concentrate resources.

[0041] In addition, when adding reduced iron powder in the present application, considering that the content of copper ions in the gold-copper smelting wastewater is very high and copper ions are more difficult to be displaced than gold ions and silver ions, a corresponding calculation formula is designed based on the displacement ratio of reduced iron powder for copper ions, and a reaction coefficient is set to further regulate the dosage of reduced iron powder, which can not only ensure that gold ions, silver ions, and copper ions in the wastewater are displaced into simple substances as much as possible, but also avoid excessive reduced iron powder resulting in too much iron hydroxide precipitation, affecting the gold and copper grades in the gold-copper slag.

[0042] In some embodiments of the present application, the concentration of copper ions in the gold-copper smelting wastewater is not less than 1000 mg / L, the concentration of gold ions is not less than 100 mg / L, the content of silver ions is not less than 10 mg / L, the ionic concentrations of lead and arsenic are not higher than 200 mg / L, the content of zinc ions is not higher than 50 mg / L, and the pH value of the gold-copper smelting wastewater is less than 2. Such wastewater is more suitable for being treated by the method provided in the present application and can achieve better technical effects.

[0043] Further, in some embodiments, the reduced iron powder used is elemental iron with a loose structure, the total iron content ≥ 88%, the particle size is less than 100 μm, and the specific surface area is 0.01 - 2 m 2 / g. This reduced iron powder is more conducive to the full progress of the displacement reaction.

[0044] Further, in some embodiments, in step S1, the lower the pH value of the gold-containing copper smelting wastewater and the higher the total mass concentration of lead ions and arsenic ions, the higher the value of α. Preferably, when the pH of the gold-containing copper smelting wastewater ≤ 0 and the total mass concentration of lead ions and arsenic ions in the gold-containing copper smelting wastewater is greater than 200 mg / L, the value range of α is preferably 1.05 - 1.10; otherwise, the value range of α is preferably 1.0 - 1.04. Among them, the pH value is the negative logarithm of the hydrogen ion concentration. When the hydrogen ion concentration is 1 mol / L, pH = 0, and when the hydrogen ion concentration > 1 mol / L, pH < 0.

[0045] In the technical solution of the embodiment of the present application, the value of the reaction coefficient α is further regulated by combining the pH value of the gold-containing copper smelting wastewater and the concentrations of lead ions and arsenic ions in the wastewater, so as to appropriately increase the dosage when the pH value of the wastewater and other ions may consume more reduced iron powder, and further ensure that gold ions, silver ions, and copper ions in the wastewater can be replaced by elemental substances as much as possible to improve the grades of gold, silver, and copper in the gold-copper slag.

[0046] Further, in some embodiments, in step S1, the reaction time is 0.5 - 1 h to ensure the full progress of the reaction.

[0047] Further, in some embodiments, in step S2, the first pH regulator is used to adjust the pH value of the iron powder displacement turbid liquid to 3.7 - 5.0; the first pH regulator is one or more of lime, sodium hydroxide, and sodium bicarbonate.

[0048] In the technical solution of the embodiment of the present application, by specifically limiting the pH value, iron ions, arsenic ions, lead ions, and a small amount of residual copper ions after the displacement treatment can be removed in the form of chemical precipitation, and it is ensured that the ion concentrations of copper, iron, and arsenic in the treated liquid phase are above 0.5 mg / L, ensuring the effective recovery of copper, further improving the grade of copper in the gold-copper slag, and effectively reducing the contents of iron and arsenic in the wastewater, and preventing iron and arsenic harmful to the cyanidation gold extraction process from affecting the smooth operation of the production system after being recycled.

[0049] Further, in some embodiments, in step S2, the oxidant is hydrogen peroxide or oxygen; when the oxidant is hydrogen peroxide, the dosage of hydrogen peroxide is more than 0.3 times the dosage of the reduced iron powder; when the oxidant is oxygen, the volume ratio of the added oxygen to the volume of the gold-copper smelting wastewater is 0.6 - 1:1.

[0050] In the technical solution of the embodiment of the present application, by adding the oxidant in the above manner, ferrous iron in the wastewater can be oxidized to ferric iron, and ferric hydroxide precipitation can be formed under the adjusted pH value environment, thereby effectively reducing the concentration of various valence iron ions in the wastewater, so as to avoid reacting with cyanide to generate iron cyanide that is difficult to remove when it is recycled to the cyanidation gold extraction process.

[0051] Further, in some embodiments, in step S2, the reaction time after adding the oxidant is 1 - 2 h to ensure that ferrous iron in the wastewater is fully oxidized and forms precipitation.

[0052] Further, in some embodiments, in step S2, the flocculant is a non-ionic flocculant, and the addition amount is 1 - 5 g / m 3 , so as to flocculate the precipitation generated by the reaction and then perform solid-liquid separation. Among them, the non-ionic flocculant is preferably a polymer electrolyte, more preferably one or more of polyoxyethylene, polyether, and polyamide, which can effectively remove suspended solids and colloidal particles in the liquid phase.

[0053] Further, in some embodiments, in step S2, after obtaining the iron-removed underflow and the iron-removed overflow by solid-liquid separation, a part of the iron-removed underflow is refluxed to step S1, and the remaining part of the iron-removed underflow is subjected to the pressure filtration and dehydration treatment; the reflux ratio of the iron-removed underflow is 5% - 25% to reduce the treatment pressure during pressure filtration and dehydration.

[0054] Further, in some embodiments, in step S3, the second pH value regulator is used to adjust the pH value to 7.0 - 7.9, and the second pH value regulator is lime or carbide slag.

[0055] In the technical solution of the embodiment of the present application, by controlling the pH value during the neutralization treatment, lead ions in the wastewater can be further removed, and the solid phase content in the neutralized turbid liquid can be controlled within a relatively low range, and the main component of this solid phase is calcium sulfate, almost free of iron, so that the flocculation and solid-liquid separation treatment can be omitted, and this neutralized turbid liquid can be directly recycled to the cyanidation gold extraction process without affecting the relevant process indexes of cyanidation gold extraction.

[0056] In some embodiments, in step S3, the reaction time after adjusting the pH value is 0.5 - 1.5 h to ensure sufficient reaction.

[0057] Some specific embodiments are listed below. It should be noted that the embodiments described below are exemplary and are only used to explain the present application, and should not be construed as a limitation to the present application.

[0058] Example 1

[0059] This embodiment provides a comprehensive treatment method for gold-containing copper smelting wastewater. The pH value of the gold-containing copper smelting wastewater targeted is -0.44, and the ion concentrations of various substances in the wastewater are shown in Table 1.

[0060] Table 1 Ion Concentrations of Various Substances in Gold-Containing Copper Smelting Wastewater (Unit: mg / L)

[0061]

[0062] The process flow schematic diagram of the comprehensive treatment method for gold-containing copper smelting wastewater provided in this embodiment is as Figure 1 shown (the dotted line in the figure represents the underflow in the sludge state), and specifically includes the following steps:

[0063] S1. Displacement treatment:

[0064] Input the gold-copper smelting wastewater into the displacement reaction tank, and add reduced iron powder (total iron component ≥ 88%, particle size about 50 μm, specific surface area about 1 m 2 / g). After stirring and reacting for 0.5 h, a turbid liquid of iron powder displacement is obtained.

[0065] Among them, the dosage of the reduced iron powder is calculated according to the following formula:

[0066] m 铁 =α×0.88×(m 铜 +m 金 +m 银 )÷1000

[0067] m 铜 、m 金 and m 银 are the mass concentrations of copper ions, gold ions, and silver ions in the gold-copper smelting wastewater, respectively, with the unit of mg / L; m 铁 is the dosage of reduced iron powder per unit volume of the gold-copper smelting wastewater, with the unit of g / L; α is the reaction coefficient.

[0068] In this embodiment, according to the pH value of the wastewater and the mass concentrations of lead and arsenic, the value of α is selected to be 1.08; thus, it is calculated that m 铁 =1.08×0.88×(5970 + 2105 + 10.94)÷1000 ≈ 7.7 g / L.

[0069] After the above replacement treatment, the ionic concentrations of various substances in the liquid phase of the iron powder replacement turbid liquid are shown in Table 2.

[0070] Table 2 Ionic Concentrations of Various Substances in the Liquid Phase of the Iron Powder Replacement Turbid Liquid (Unit: mg / L)

[0071]

[0072] Recovery Rates of Various Metals ρ Are calculated according to the following formula:

[0073] ;

[0074] Where C 0 represents the concentration of metal elements in the liquid phase before treatment, C 1 represents the concentration of metal elements in the liquid phase after treatment.

[0075] According to the data in Table 1 and Table 2, using the above formula, it can be calculated that the recovery rate of gold after the replacement treatment is greater than 99.99%, the recovery rate of silver is greater than 99.9%, and the recovery rate of copper is greater than 99.8%.

[0076] S2. Iron Removal Treatment

[0077] Input the iron powder replacement turbid liquid obtained in step S1 into the iron removal reaction pool. Use sodium hydroxide solution with a mass concentration of 10% as the first pH regulator, and add it to the iron removal reaction pool through the pH regulation system 1 to adjust the pH value of the iron powder replacement turbid liquid to 3.8. Then, add hydrogen peroxide solution with a mass concentration of 30% (density 1.1 g / mL) with a dosing amount of 10 mL / L through the oxidant dosing system. The dosing amount of the oxidant hydrogen peroxide is equivalent to 3.3 g / L, which is 0.43 times the dosing amount of reduced iron powder. Stir and react for 1.5 h to oxidize divalent iron to trivalent iron, and at the same time remove the remaining copper ions, arsenic ions, and part of the lead ions from the wastewater in the form of chemical precipitation. After the reaction, the iron removal turbid liquid is obtained. The ionic concentrations of various substances in the liquid phase of the iron removal turbid liquid are shown in Table 3.

[0078] Table 3 Ionic Concentrations of Various Substances in the Liquid Phase of the Iron Removal Turbid Liquid (Unit: mg / L)

[0079]

[0080] Combining Tables 1 - 3, it can be seen that iron ions, copper ions, and arsenic ions in the wastewater are fully removed, and their concentrations are reduced to above 0.5 mg / L, further increasing the comprehensive recovery rate of copper to above 99.99%.

[0081] Input the iron removal turbid liquid into the iron removal flocculation reaction pool, and through the flocculant dosing system at 1 g / m3 The non-ionic flocculant polyamide is added to the iron removal flocculation reaction tank according to the dosage, and then input into the iron removal flocculation sedimentation tank. The iron removal thickener is used for solid-liquid separation to obtain the iron removal overflow and the iron removal underflow in the form of sludge. Among them, a part of the iron removal underflow is refluxed to the displacement mud mixing tank and flows into the displacement reaction tank through the displacement mud mixing tank, and the reflux ratio is controlled at 20%; the remaining iron removal underflow is subjected to pressure filtration and dehydration treatment to obtain gold-copper slag and filtrate. In this gold-copper slag, the grade of copper reaches 28.6%, and the grade of gold reaches 7.51%, meeting the product requirements of gold concentrate and gold-copper ore, with extremely high utilization value, and can be sold as high-price gold-copper resources.

[0082] S3. Neutralization treatment

[0083] The iron removal overflow and filtrate obtained in step S2 are input into the neutralization reaction tank. Lime is used as the second pH regulator and is added to the neutralization reaction tank through the pH regulation system 2 to adjust the pH value of the liquid phase to 7.5, further removing lead ions in the wastewater. After reacting for 1 h, a neutralization turbid liquid is obtained.

[0084] The ionic concentrations of various substances in the liquid phase of the neutralization turbid liquid are shown in Table 4.

[0085] Table 4 Ionic concentrations of various substances in the liquid phase of the neutralization turbid liquid (unit: mg / L)

[0086]

[0087] It can be seen from Table 4 that the concentrations of various substances in the liquid phase of the neutralization turbid liquid are relatively low, meeting the reuse conditions.

[0088] In addition, the solid content in the neutralization turbid liquid is 2%, and the main component of this solid is calcium sulfate, and the iron content is relatively low, less than 0.5% of the solid content.

[0089] Therefore, the neutralization turbid liquid prepared in this embodiment can be directly reused as a whole in the cyanidation leaching process of cyanide gold extraction without having an adverse impact on the production indexes of cyanide gold extraction. In this way, not only the treatment process is effectively reduced, the treatment efficiency is improved, but also the neutralization turbid liquid can be fully reused, avoiding the generation of waste slag, and improving the resource utilization rate.

[0090] Examples 2-3 and Comparative Examples 1-2

[0091] Examples 2 to 3 and Comparative Examples 1 to 2 respectively provide a comprehensive treatment method for gold-containing copper smelting wastewater. Compared with Example 1, the difference lies in changing the value of the reaction coefficient α in step S1, adding different amounts of reduced iron powder. The addition amounts of reduced iron powder in each example and comparative example are shown in Table 5. At the same time, the addition amount of hydrogen peroxide solution in step S2 in each example and comparative example is also adaptively adjusted according to the addition amount of reduced iron powder, so that the addition amount of the oxidant hydrogen peroxide is 0.43 times the addition amount of reduced iron powder. The remaining steps are the same as those in Example 1 and will not be elaborated here.

[0092] Table 5 Addition amounts of reduced iron powder in Examples 2 to 3 and Comparative Examples 1 to 2

[0093]

[0094] After treating the gold-containing copper smelting wastewater according to the methods provided in Examples 2 to 3 and Comparative Examples 1 to 2, the relevant technical index results are shown in Table 6.

[0095] Table 6 Technical index results of Examples 2 to 3 and Comparative Examples 1 to 2

[0096]

[0097] As can be seen from Table 6, the addition amount of reduced iron powder in step S1 needs to meet the relevant proportional requirements. If it is lower than the specified addition ratio, the comprehensive recovery rates of gold and copper will decrease; if it is higher than the specified addition ratio, the generation amount of gold-copper slag will increase, resulting in a decrease in the grades of gold and copper in the gold-copper slag. At the same time, more oxidant needs to be consumed, increasing the treatment cost.

[0098] Example 4 and Comparative Example 3

[0099] Example 4 and Comparative Example 3 respectively provide a comprehensive treatment method for gold-containing copper smelting wastewater. Compared with Example 1, the difference lies in changing the addition amount of hydrogen peroxide solution in step S2. The addition amounts of hydrogen peroxide solution in Example 4 and Comparative Example 3 are shown in Table 7. The remaining steps are the same as those in Example 1 and will not be elaborated here.

[0100] Table 7 Addition amounts of hydrogen peroxide solution in Example 4 and Comparative Example 3

[0101]

[0102] After treating the gold-containing copper smelting wastewater according to the methods provided in Example 4 and Comparative Example 3, the relevant technical index results are shown in Table 8.

[0103] Table 8 Technical index results of Example 4 and Comparative Example 3

[0104]

[0105] As can be seen from Table 8, when the dosage of the oxidant in Step S2 is less than 0.3 times the dosage of the reduced iron powder, divalent iron ions will enter the neutralization turbid liquid, resulting in a relatively high iron content in the solid phase of the neutralization turbid liquid. The relatively high iron content will increase the consumption of gold extraction agents such as sodium cyanide in the cyanidation production process, which does not meet the requirements of the recycled water for the cyanidation gold extraction process.

[0106] Examples 5 - 6 and Comparative Examples 4 - 5

[0107] Examples 5 - 6 and Comparative Examples 4 - 5 respectively provide a comprehensive treatment method for gold - containing copper smelting wastewater. Compared with Example 1, the difference lies in changing the adjusted pH value in Step S2. The corresponding pH values in each example and comparative example are shown in Table 9. The remaining steps are the same as those in Example 1 and will not be elaborated here.

[0108] Table 9 pH values in Step S2 of Examples 5 - 6 and Comparative Examples 4 - 5

[0109]

[0110] After treating the gold - containing copper smelting wastewater according to the methods provided in Examples 5 - 6 and Comparative Examples 4 - 5, the results of relevant technical indicators are shown in Table 10.

[0111] Table 10 Results of technical indicators of Examples 5 - 6 and Comparative Examples 4 - 5

[0112]

[0113] As can be seen from Table 10, the pH value in Step S2 needs to be controlled within an appropriate range. When it is too low, iron ions will also enter the neutralization turbid liquid, affecting its reuse. If the pH value is higher than 5.0, due to the generation of a large amount of waste residue, the grades of gold and copper in the gold - copper slag will decrease significantly, affecting its economic value.

[0114] Examples 7 - 8 and Comparative Examples 6 - 7

[0115] Examples 7 - 8 and Comparative Examples 6 - 7 respectively provide a comprehensive treatment method for gold - containing copper smelting wastewater. Compared with Example 1, the difference lies in changing the adjusted pH value in Step S3. The corresponding pH values in each example and comparative example are shown in Table 11. The remaining steps are the same as those in Example 1 and will not be elaborated here.

[0116] Table 11 pH values in Step S3 of Examples 7 - 8 and Comparative Examples 6 - 7

[0117]

[0118] After treating the gold-containing copper smelting wastewater according to the methods provided in Examples 7-8 and Comparative Examples 6-7, the results of relevant technical indicators are shown in Table 12.

[0119] Table 12 Technical Indicator Results of Examples 7-8 and Comparative Examples 6-7

[0120]

[0121] As can be seen from Table 12, the adjustment of the pH value in step S3 directly determines whether the neutralized turbid liquid meets the requirements for recycled water in the cyanidation gold extraction process. If the pH value is relatively low, it will cause the neutralized turbid liquid to be acidic and the concentration of impurity metal ions in the liquid phase to be too high, so it cannot be recycled; if the pH value is relatively high, not only will the dosage of the second pH regulator increase, resulting in an increase in the chemical cost, but also the solid content in the neutralized turbid liquid will be too high, making it not suitable for directly recycling the neutralized turbid liquid without solid-liquid separation.

[0122] In summary, the present application provides a comprehensive treatment method for gold-containing copper smelting wastewater, belonging to the technical field of wastewater treatment. The method includes: adding reduced iron powder to the gold-containing copper smelting wastewater, and obtaining a turbid liquid after iron powder replacement through sufficient reaction; adding a first pH regulator to the turbid liquid after iron powder replacement, adjusting the pH value and then adding an oxidant, and obtaining a turbid liquid after iron removal through sufficient reaction; adding a flocculant to the turbid liquid after iron removal, and after sufficient flocculation, obtaining an underflow after iron removal and an overflow after iron removal through solid-liquid separation; performing pressure filtration dehydration treatment on the underflow after iron removal to obtain gold-copper slag and filtrate after pressure filtration; mixing the overflow after iron removal and the filtrate after pressure filtration, and adding a second pH regulator, adjusting the pH value and then reacting sufficiently to obtain a neutralized turbid liquid. Through the above method, while effectively recovering valuable substances, the present application avoids the impact of harmful metal ions in the wastewater on the production system or the ecological environment, and no hazardous waste is generated throughout the process, achieving the unity of environmental benefits and economic benefits.

[0123] It should be noted that the present application is not limited to the above embodiments. The above embodiments are only examples, and embodiments with the same structure and the same function and effect as the technical idea within the technical solution scope of the present application are all included in the technical scope of the present application. In addition, within the scope not departing from the gist of the present application, various modifications that those skilled in the art can think of and other ways constructed by combining some constituent elements in the embodiments are also included in the scope of the present application.

Claims

1. A comprehensive treatment method for gold-containing copper smelting wastewater, characterized in that: The steps include: S1. Adding a predetermined amount of reduced iron powder to the gold-containing copper smelting wastewater to obtain an iron powder-replaced turbid liquid after sufficient reaction; The dosage of the reduced iron powder meets the following conditions: m 铁 =α×0.88×(m 铜 +m 金 +m 银 )÷1000 Among them, m 铜 、m 金 and m 银 are the mass concentrations of copper ions, gold ions and silver ions in the gold-copper smelting wastewater, respectively, in mg / L; m 铁 is the dosage of reduced iron powder per unit volume of gold-copper smelting wastewater, in g / L; α is the reaction coefficient, when the pH of the gold-containing copper smelting wastewater is ≤0, and the total mass concentration of lead ions and arsenic ions in the gold-containing copper smelting wastewater is greater than 200 mg / L, the value range of α is 1.05~1.10; otherwise, the value range of α is 1.0~1.04; S2. Adding a first pH value adjusting agent to the iron powder replacement turbid liquid, adjusting the pH value to 3.7-5.0, and then adding an oxidant to obtain a deironing turbid liquid after sufficient reaction; adding a flocculant to the deironing turbid liquid, and after sufficient flocculation, obtaining a deironing underflow and a deironing overflow by solid-liquid separation; performing filter press dehydration treatment on the deironing underflow to obtain a gold-copper slag and a filtrate press; S3. The iron removal overflow and the filtrate are mixed, and a second pH adjuster is added to adjust the pH value to 7.0-7.9 and then fully reacted to obtain a neutralized turbid liquid.

2. The comprehensive treatment method for gold-containing copper smelting wastewater according to claim 1 is characterized in that: In step S1, the reaction time is 0.5-1 h.

3. The comprehensive treatment method for gold-containing copper smelting wastewater according to claim 1 is characterized in that: In step S2, the first pH adjuster is one or more of lime, sodium hydroxide, and sodium bicarbonate.

4. The comprehensive treatment method for gold-containing copper smelting wastewater according to claim 1 is characterized in that: In step S2, the oxidant is hydrogen peroxide or oxygen; when the oxidant is hydrogen peroxide, the dosage of hydrogen peroxide is more than 0.3 times the dosage of the reduced iron powder; when the oxidant is oxygen, the volume ratio of the added volume of oxygen to the volume of the gold and copper smelting wastewater is 0.6~1:

1.

5. The comprehensive treatment method for gold-containing copper smelting wastewater according to claim 1 is characterized in that: In step S2, the reaction time after adding the oxidant is 1 to 2 hours.

6. The comprehensive treatment method for gold-containing copper smelting wastewater according to claim 1 is characterized in that: In step S2, the flocculant is a nonionic flocculant, and the amount added is 1-5 g / m 3 .

7. The comprehensive treatment method for gold-containing copper smelting wastewater according to claim 1 is characterized in that: In step S2, after the iron removal underflow and the iron removal overflow are obtained through solid-liquid separation, a part of the iron removal underflow is returned to step S1, and the remaining part of the iron removal underflow is subjected to the filter press dehydration treatment; The reflux ratio of the iron removal bottom flow is 5% to 25%.

8. The comprehensive treatment method for gold-containing copper smelting wastewater according to claim 1 is characterized in that: In step S3, the second pH adjuster is lime or carbide slag.

9. The comprehensive treatment method for gold-containing copper smelting wastewater according to claim 1, characterized in that: In step S3, the reaction time after adjusting the pH value is 0.5-1.5 h.

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