Comprehensive treatment method for gold-copper-containing smelting wastewater

Abstract

The invention provides a comprehensive treatment method for gold-copper-containing smelting wastewater, and belongs to the technical field of wastewater treatment. The method comprises the following steps: adding reduced iron powder into the gold-containing copper smelting wastewater, and fully reacting to obtain an iron powder replacement turbid solution; a first pH value regulator is added into the iron powder replacement turbid solution, an oxidizing agent is added after the pH value is regulated, and an iron-removed turbid solution is obtained after full reaction; adding a flocculating agent into the iron-removed turbid liquid, fully flocculating, and carrying out solid-liquid separation to obtain iron-removed underflow and iron-removed overflow; carrying out filter pressing dehydration treatment on the iron-removed underflow to obtain gold-copper slag and filter pressing liquid; and mixing the iron-removed overflow and the press filtrate, adding a second pH value regulator, and fully reacting after regulating the pH value to obtain a neutralized turbid solution. By means of the mode, valuable substances are effectively recycled, meanwhile, harmful metal ions in the wastewater are prevented from affecting a production system or the ecological environment, hazardous waste is not generated in the whole process, and unification of environmental benefits and economic benefits is achieved.

Description

Technical Field

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

[0002] Cyanide 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 in the future. It mainly includes cyanide leaching, carbon leaching gold, gold-loaded carbon pickling, electrolytic recovery of gold mud, gold mud smelting and other processes. Among them, in the process of gold-loaded carbon pickling and gold mud smelting, a certain amount of smelting wastewater is usually generated. These smelting wastewaters often contain gold, silver, copper, lead, arsenic and other substances, 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 have an impact on 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 the valuable substances through acid desorption, electrolysis, etc., but this process still produces a large amount of acidic wastewater, 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 into the gold production system, it will have a negative impact on the process indicators of gold production. Therefore, how to achieve the recovery of valuable substances while eliminating the enrichment of other harmful substances in the production system is a current research hotspot.

[0004] In the prior art, the sulfidation method is mainly used to recover the required substances in the 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 a sulfiding agent, valuable substances such as zinc and copper in the wastewater are recovered in the form of sulfide precipitation at different pH values, and other impurity ions are removed by neutralization reaction, but the neutralized slag obtained after the neutralization reaction belongs to general solid waste, and the liquid after neutralization also needs to be aerated, which cannot be directly reused, and the disposal process is complicated and the cost is high. The patent with the publication number CN103145267A provides a method for recovering copper sulfide and iron hydroxide in acidic wastewater of gold and copper mines by sulfidation method, by adding alkali to make iron hydroxide flocculate and precipitate, and then recover copper sulfide by adding sodium sulfide, and finally recover gypsum by adding limestone. This step-by-step recovery of different products is not only complicated, but also each product is actually mixed with more harmful substances, and it needs to be sold as a valuable substance after subsequent fine processing. Moreover, different recovery methods are usually required for smelting wastewater of different compositions. The above method is mainly suitable for the recovery of copper, and it is 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 technology, the present application provides a comprehensive treatment method for gold-containing copper smelting wastewater, by subjecting the gold-containing copper smelting wastewater to replacement treatment, iron removal treatment and neutralization treatment in sequence, and accurately controlling parameters such as pH value and reagent dosage during the treatment process, while effectively recovering valuable substances such as gold, silver and copper, harmful metal ions in the wastewater are avoided from affecting the production system or the ecological environment, and the treatment process does not generate hazardous waste, thereby achieving the unity of environmental and economic benefits.

[0007] The present application embodiment provides a comprehensive treatment method for gold-containing copper smelting wastewater, comprising the following steps: 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 and copper smelting wastewater, in g / L; α is the reaction coefficient, ranging from 1.0 to 1.1; S2. adding a first pH value adjusting agent to the iron powder replacement turbid liquid, adding an oxidant after adjusting the pH value, and obtaining an iron removal turbid liquid after sufficient reaction; adding a flocculant to the iron removal turbid liquid, and obtaining an iron removal underflow and an iron removal overflow after sufficient flocculation by solid-liquid separation; performing filter press dehydration treatment on the iron removal underflow to obtain gold-copper slag and a filtrate; S3. The iron removal overflow and the filtrate are mixed, and a second pH adjuster is added to fully react after adjusting the pH value to obtain a neutralized turbid liquid.

[0008] 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.

[0009] In some embodiments, in step S1, the reaction time is 0.5-1 h.

[0010] In some embodiments, in step S2, the first pH adjuster is used to adjust the pH value of the iron powder-substituted turbid liquid to 3.7-5.0; the first pH adjuster is one or more of lime, sodium hydroxide, and sodium bicarbonate.

[0011] 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 volume of oxygen to the volume of the gold and copper smelting wastewater is 0.6~1:1.

[0012] In some embodiments, in step S2, the reaction time after adding the oxidant is 1 to 2 hours.

[0013] In some embodiments, in step S2, the flocculant is a non-ionic flocculant, and the amount added is 1-5 g / m 3 .

[0014] In some embodiments, in step S2, after solid-liquid separation to obtain iron removal underflow and iron removal overflow, a portion of the iron removal underflow is refluxed 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 underflow is 5% to 25%.

[0015] In some embodiments, in step S3, the second pH adjuster is used to adjust the pH value to 7.0-7.9, and the second pH adjuster is lime or carbide slag.

[0016] In some embodiments, in step S3, the reaction time after adjusting the pH value is 0.5 to 1.5 hours.

[0017] The beneficial effects of this application are: The comprehensive treatment method of gold-containing copper smelting wastewater provided in the present application is to sequentially perform replacement treatment, iron removal treatment, and neutralization treatment on the gold-containing copper smelting wastewater, and directly perform subsequent iron removal treatment without flocculation after the replacement reaction, and further regulate the amount of reduced iron powder added in the replacement treatment process, the pH value during the iron removal treatment, the amount of oxidant added, and the pH value of the neutralization treatment, so that the valuable substances in the gold-containing copper smelting wastewater can be simply and efficiently recovered, and the final product is only gold-copper slag and neutralized turbid liquid. Among them, the gold-copper slag has a high content of gold and copper, which can meet the requirements of gold concentrate and copper concentrate products, and the content of other harmful impurities is low, and it can be directly sold as a high-priced substance; the liquid phase of the neutralized turbid liquid has very little harmful impurities, and the main component of the solid phase is calcium sulfate, and the iron content is low, so that the neutralized turbid liquid meets the recovery requirements of the cyanide gold extraction process, and can be directly reused in the cyanide leaching process in the cyanide 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 in 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. The entire treatment process does not generate hazardous waste, reduces the environmental risks of waste residue storage in conventional water treatment processes, and achieves the unity of economic and environmental benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solution of the present application, the following is a brief introduction to the drawings used in the present application. Obviously, the drawings described below are only some embodiments of the present application, and for ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0019] Figure 1 This is a schematic diagram of the process flow of the comprehensive treatment method for gold-containing copper smelting wastewater provided in Example 1 of the present application. DETAILED DESCRIPTION

[0020] The following embodiments of the technical solution of the present application are described in detail in conjunction with the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present application, and are therefore only used as examples, and cannot be used to limit the scope of protection of the present application.

[0021] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by technicians 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" in the specification and claims of this application and the above-mentioned figure descriptions and any variations thereof are intended to cover non-exclusive inclusions.

[0022] 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 indicating the number, specific order or primary and secondary relationship of the indicated technical features.

[0023] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0024] For gold-containing copper smelting wastewater, conventional treatment methods are not only complicated in process, but also difficult to effectively utilize all the treatment products. They usually produce slag or waste liquid with high content of harmful substances, which will affect the production system or ecological environment.

[0025] In order to solve the above problems, the present application provides a comprehensive treatment method for gold-containing copper smelting wastewater, by sequentially subjecting the gold-containing copper smelting wastewater to replacement treatment, iron removal treatment and neutralization treatment, and accurately controlling parameters such as pH value and reagent dosage during the treatment process. While effectively recovering valuable substances such as gold, silver and copper, the method avoids the impact of harmful metal ions in the wastewater on the production system or the ecological environment, and the treatment process does not generate hazardous waste, thereby achieving the unity of environmental and economic benefits.

[0026] Specifically, the present application embodiment provides a comprehensive treatment method for gold-containing copper smelting wastewater, comprising the following steps: 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 and copper smelting wastewater, in g / L; α is the reaction coefficient, ranging from 1.0 to 1.1; S2. adding a first pH value adjusting agent to the iron powder replacement turbid liquid, adding an oxidant after adjusting the pH value, and obtaining an iron removal turbid liquid after sufficient reaction; adding a flocculant to the iron removal turbid liquid, and obtaining an iron removal underflow and an iron removal overflow after sufficient flocculation by solid-liquid separation; performing filter press dehydration treatment on the iron removal underflow to obtain gold-copper slag and a filtrate; S3. The iron removal overflow and the filtrate are mixed, and a second pH adjuster is added to fully react after adjusting the pH value to obtain a neutralized turbid liquid.

[0027] In the technical scheme of the embodiment of the present application, by adding reduced iron powder to replace the copper ions, gold ions and silver ions in the gold-containing copper smelting wastewater, the valuable metal ions in the gold-containing copper smelting wastewater can be converted into corresponding metal elements, so as to realize the recovery of valuable metals in the wastewater. On this basis, the present application does not flocculate and solid-liquid separate the iron powder replacement turbid liquid obtained after the replacement in a conventional manner, but sends the wastewater after the replacement treatment and the metal element produced after the replacement reaction into the subsequent iron removal process together. In this way, after the iron removal treatment, no iron removal slag with high iron, lead and arsenic content that needs to be treated as hazardous waste will be collected, but high-value gold-copper slag will be collected, and 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 precipitate and a small amount of lead and arsenic precipitate, which effectively reduces the concentration of harmful metal ions in the wastewater, and a small amount of lead and arsenic will not affect the gold and copper slag with high gold and copper content as high-value gold concentrate and copper concentrate resources for sale.

[0028] In addition, when adding reduced iron powder, the present application takes into account that the content of copper ions in the gold-containing copper smelting wastewater is very high, and copper ions are more difficult to be replaced than gold ions and silver ions. A corresponding calculation formula is designed based on the ratio of copper ions replaced by reduced iron powder, and a reaction coefficient is set to further regulate the amount of reduced iron powder added, which can not only ensure that the gold ions, silver ions, and copper ions in the wastewater are replaced into single substances as much as possible, but also avoid excessive reduced iron powder causing excessive precipitation of iron hydroxide subsequently produced, affecting the grade of gold and copper in the gold-copper slag.

[0029] In some embodiments of the present application, the concentration of copper ions in the gold-containing 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 concentration of lead and arsenic ions is 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-containing copper smelting wastewater is less than 2. This type of wastewater is more suitable for treatment using the method provided in the present application, and can achieve better technical effects.

[0030] Furthermore, in some embodiments, the reduced iron powder used is loosely structured elemental iron, with a total iron content of ≥88%, a particle size of less than 100 μm, and a specific surface area of ​​0.01 to 2 m 2 / g, the reduced iron powder is more conducive to the full replacement reaction.

[0031] Furthermore, 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 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 preferably 1.05~1.10; in addition, 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 is>1 mol / L, pH<0.

[0032] In the technical solution of the embodiment of the present application, the value of the reaction coefficient α is further regulated in combination with the pH value of the gold-containing copper smelting wastewater and the concentrations of lead ions and arsenic ions in the wastewater, so that the dosage is appropriately increased when the pH value of the wastewater and other ions are likely to consume more reduced iron powder, further ensuring that the gold ions, silver ions and copper ions in the wastewater can be replaced into single substances as much as possible, so as to improve the grade of gold, silver and copper in the gold-copper slag.

[0033] Furthermore, in some embodiments, in step S1, the reaction time is 0.5 to 1 h to ensure that the reaction proceeds fully.

[0034] Furthermore, in some embodiments, in step S2, the first pH adjuster is used to adjust the pH value of the iron powder-substituted turbid liquid to 3.7-5.0; the first pH adjuster is one or more of lime, sodium hydroxide, and sodium bicarbonate.

[0035] 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 copper ions remaining after the replacement treatment can be removed in the form of chemical precipitation, and the ion concentrations of copper, iron and arsenic in the treated liquid phase are ensured to be above 0.5 mg / L, thereby ensuring that copper is effectively recovered, further improving the copper grade in the gold-copper slag, and effectively reducing the iron and arsenic content in the wastewater, which can prevent iron and arsenic that are harmful to the cyanide gold extraction process from being reused and affecting the smooth operation of the production system.

[0036] Furthermore, 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 volume of oxygen to the volume of the gold-copper smelting wastewater is 0.6~1:1.

[0037] In the technical solution of the embodiment of the present application, by adding an oxidant in the above manner, the divalent iron in the wastewater can be oxidized into trivalent iron, and iron hydroxide precipitate is formed under the adjusted pH environment, thereby effectively reducing the concentration of iron ions of various valence states in the wastewater to prevent it from reacting with cyanide to form difficult-to-remove ferrocyanide when it is reused in the cyanide gold extraction process.

[0038] Furthermore, in some embodiments, in step S2, the reaction time after adding the oxidant is 1 to 2 hours to ensure that the divalent iron in the wastewater is fully oxidized and forms a precipitate.

[0039] Furthermore, in some embodiments, in step S2, the flocculant is a non-ionic flocculant, and the amount added is 1-5 g / m 3 , so as to flocculate the precipitate 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 matter and colloidal particles in the liquid phase.

[0040] Furthermore, in some embodiments, 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 refluxed 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 underflow is 5% to 25% so as to reduce the processing pressure during filter press dehydration.

[0041] Furthermore, in some embodiments, in step S3, the second pH adjuster is used to adjust the pH value to 7.0-7.9, and the second pH adjuster is lime or carbide slag.

[0042] In the technical solution of the embodiment of the present application, by regulating the pH value during the neutralization treatment, the 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. The main component of the solid phase is calcium sulfate, and it contains almost no iron, so that the flocculation and solid-liquid separation treatments can be omitted, and the neutralized turbid liquid can be directly reused in the cyanide gold extraction process without affecting the relevant process indicators of cyanide gold extraction.

[0043] In some embodiments, in step S3, the reaction time after adjusting the pH value is 0.5-1.5 hours to ensure sufficient reaction.

[0044] 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 limiting the present application.

[0045] Example 1 This embodiment provides a comprehensive treatment method for gold-containing copper smelting wastewater. The pH value of the gold-containing copper smelting wastewater is -0.44, and the ion concentration of each substance in the wastewater is shown in Table 1.

[0046] Table 1 Ion concentration of various substances in gold-containing copper smelting wastewater (unit: mg / L) The process flow diagram of the comprehensive treatment method for gold-containing copper smelting wastewater provided in this embodiment is as follows: Figure 1 As shown in the figure (the dotted line in the figure represents the bottom flow in the sludge state), the specific steps include: S1. Replacement processing: The gold and copper smelting wastewater is fed into the replacement reaction tank and reduced iron powder (total iron content ≥ 88%, particle size about 50 μm, specific surface area about 1 m 2 / g), and stirred for 0.5h to obtain an iron powder-substituted turbid liquid.

[0047] The dosage of reduced iron powder is calculated according to the following formula: m 铁 =α×0.88×(m 铜 +m 金 +m 银 )÷1000 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 and copper smelting wastewater, in g / L; α is the reaction coefficient.

[0048] In this embodiment, the value of α is set to 1.08 according to the pH value of the wastewater and the mass concentration of lead and arsenic; thus, m is calculated to be 铁 =1.08×0.88×(5970+2105+10.94)÷1000≈7.7g / L.

[0049] After the above replacement treatment, the ion concentrations of various substances in the liquid phase of the iron powder-substituted turbid solution are shown in Table 2.

[0050] Table 2 Ion concentration of each substance in the liquid phase of the turbid solution replaced by iron powder (unit: mg / L) Recovery rate of each metal ρ Calculate according to the following formula: ; in, 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.

[0051] According to the data in Table 1 and Table 2, it can be calculated using the above formula that the recovery rate of gold after 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%.

[0052] S2. Iron removal treatment The iron powder replacement turbid liquid obtained in step S1 is input into the iron removal reaction tank, and a sodium hydroxide solution with a mass concentration of 10% is used as the first pH value regulator, and it is added to the iron removal reaction tank through the pH value adjustment system 1, and the pH value of the iron powder replacement turbid liquid is adjusted to 3.8, and a hydrogen peroxide solution with a mass concentration of 30% (density of 1.1g / mL) is added at a dosage of 10mL / L through the oxidant addition system, which is equivalent to the dosage of the oxidant hydrogen peroxide solution of 3.3g / L, which is 0.43 times the dosage of the reduced iron powder, and the reaction is stirred for 1.5h to oxidize the divalent iron to trivalent iron, and at the same time, the remaining copper ions, arsenic ions and part of the lead ions are removed from the wastewater in the form of chemical precipitation, and the iron removal turbid liquid is obtained after the reaction. In the liquid phase of the iron removal turbid liquid, the ion concentration of each substance is shown in Table 3.

[0053] Table 3 Ion concentration of each substance in the liquid phase of the iron removal turbid solution (unit: mg / L) From Tables 1-3, it can be seen that the iron ions, copper ions and arsenic ions in the wastewater are fully removed, and their concentrations are reduced to above 0.5 mg / L, which further increases the comprehensive recovery rate of copper to above 99.99%.

[0054] The iron removal turbid liquid is input into the iron removal flocculation reaction tank, and the flocculant is added at 1g / m 3The nonionic flocculant polyamide is added to the iron removal flocculation reaction tank in an amount of , and then input into the iron removal flocculation sedimentation tank, and the iron removal thickener is used for solid-liquid separation to obtain the iron removal overflow and the iron removal underflow in a sludge state. Among them, a part of the iron removal underflow is returned 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 to be 20%; the remaining iron removal underflow is subjected to filter press dehydration treatment to obtain gold-copper slag and filter press liquid. The copper grade of the gold-copper slag reaches 28.6%, and the gold grade reaches 7.51%, which meets the product requirements of gold concentrate and copper-gold mine, has extremely high utilization value, and can be sold as a high-priced gold-copper resource.

[0055] S3. Neutralization treatment The iron removal overflow and filtrate obtained in step S2 are input into the neutralization reaction tank, and lime is used as the second pH adjuster. It is added into the neutralization reaction tank through the pH adjustment system 2 to adjust the pH value of the liquid phase to 7.5 to further remove the lead ions in the wastewater. After reacting for 1 hour, a neutralized turbid liquid is obtained.

[0056] The ion concentrations of the various substances in the liquid phase of the neutralized turbid solution are shown in Table 4.

[0057] Table 4 Ion concentration of each substance in the liquid phase of the neutralized turbid solution (unit: mg / L) It can be seen from Table 4 that the concentration of each substance in the liquid phase of the neutralized turbid liquid is low, which meets the reuse conditions.

[0058] In addition, the solid content in the neutralized turbid liquid is 2%, and the main component of the solid phase is calcium sulfate, and the iron content is low, less than 0.5% of the solid content.

[0059] Therefore, the neutralized turbid liquid prepared in this embodiment can be directly reused in the cyanide leaching process of cyanide gold extraction without solid-liquid separation, which will not have an adverse effect on the production indicators of cyanide gold extraction. This not only effectively reduces the treatment process and improves the treatment efficiency, but also enables the neutralized turbid liquid to be fully reused, avoiding the generation of waste slag and improving resource utilization.

[0060] Examples 2-3 and Comparative Examples 1-2 Embodiments 2 to 3 and comparative examples 1 to 2 respectively provide a comprehensive treatment method for gold-containing copper smelting wastewater. Compared with embodiment 1, the difference is that the value of the reaction coefficient α in step S1 is changed, and different amounts of reduced iron powder are added. The amount of reduced iron powder added in each embodiment and comparative example is shown in Table 5. At the same time, the amount of hydrogen peroxide solution added in step S2 in each embodiment and comparative example is also adaptively adjusted with the amount of reduced iron powder added, so that the amount of oxidant hydrogen peroxide added is 0.43 times the amount of reduced iron powder added. The remaining steps are consistent with embodiment 1 and are not repeated here.

[0061] Table 5 Dosage of reduced iron powder in Examples 2-3 and Comparative Examples 1-2 After treating the gold-containing copper smelting wastewater according to the methods provided in Examples 2-3 and Comparative Examples 1-2, the relevant technical indicator results are shown in Table 6.

[0062] Table 6 Technical index results of Examples 2-3 and Comparative Examples 1-2 It can be seen from Table 6 that the dosage of reduced iron powder in step S1 must meet the relevant ratio requirements. If it is lower than the specified dosage ratio, the comprehensive recovery rate of gold and copper will be reduced; if it is higher than the specified dosage ratio, the amount of gold-copper slag generated will increase, thereby reducing the grade of gold and copper in the gold-copper slag. At the same time, more oxidants need to be consumed, increasing the processing cost.

[0063] Example 4 and Comparative Example 3 Example 4 and Comparative Example 3 respectively provide a comprehensive treatment method for gold-containing copper smelting wastewater. Compared with Example 1, the difference is that the dosage of the hydrogen peroxide solution in step S2 is changed. The dosage of the hydrogen peroxide solution in Example 4 and Comparative Example 3 is shown in Table 7. The remaining steps are consistent with Example 1 and are not repeated here.

[0064] Table 7 Dosage of hydrogen peroxide solution in Example 4 and Comparative Example 3 After treating the gold-containing copper smelting wastewater according to the methods provided in Example 4 and Comparative Example 3, the relevant technical indicator results are shown in Table 8.

[0065] Table 8 Technical index results of Example 4 and Comparative Example 3 It can be seen from Table 8 that 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 neutralized turbid liquid, resulting in a higher iron content in the solid phase of the neutralized turbid liquid. The higher iron content will increase the consumption of gold extraction agents such as sodium cyanide in the cyanide production process, which does not meet the return water requirements of the cyanide gold extraction process.

[0066] Examples 5-6 and Comparative Examples 4-5 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 is that the adjusted pH value in step S2 is changed. The corresponding pH values ​​in each embodiment and comparative example are shown in Table 9. The remaining steps are consistent with Example 1 and are not repeated here.

[0067] Table 9 pH value in step S2 in Examples 5-6 and Comparative Examples 4-5 After treating the gold-containing copper smelting wastewater according to the methods provided in Examples 5-6 and Comparative Examples 4-5, the relevant technical indicator results are shown in Table 10.

[0068] Table 10 Technical index results of Examples 5-6 and Comparative Examples 4-5 It can be seen from Table 10 that the pH value in step S2 needs to be controlled within an appropriate range. When the pH value is too low, iron ions will enter and neutralize the turbid liquid, affecting its recycling. If the pH value is higher than 5.0, due to the generation of a large amount of waste slag, the grade of gold and copper in the gold-copper slag will be significantly reduced, affecting its economic value.

[0069] Examples 7-8 and Comparative Examples 6-7 Examples 7 to 8 and Comparative Examples 6 to 7 respectively provide a comprehensive treatment method for gold-containing copper smelting wastewater. Compared with Example 1, the difference is that the adjusted pH value in step S3 is changed. The corresponding pH values ​​in each embodiment and comparative example are shown in Table 11. The remaining steps are consistent with Example 1 and are not repeated here.

[0070] Table 11 pH value in step S3 in Examples 7-8 and Comparative Examples 6-7 After treating the gold-containing copper smelting wastewater according to the methods provided in Examples 7-8 and Comparative Examples 6-7, the relevant technical indicator results are shown in Table 12.

[0071] Table 12 Technical index results of Examples 7 to 8 and Comparative Examples 6 to 7 It can be seen from Table 12 that the adjustment of the pH value in step S3 directly determines whether the neutralized turbid liquid meets the requirements for water reuse in the cyanide gold extraction process. If the pH value is relatively low, the neutralized turbid liquid will become acidic, and the concentration of impurity metal ions in the liquid phase will be too high and cannot be reused; if the pH value is relatively high, not only the amount of the second pH value regulator is increased, which increases the cost of the agent, but also the solid content in the neutralized turbid liquid is too high, which is not suitable for direct reuse of the neutralized turbid liquid without solid-liquid separation.

[0072] In summary, the present application provides a comprehensive treatment method for gold-containing copper smelting wastewater, which belongs to the field of wastewater treatment technology. The method comprises: adding reduced iron powder to the gold-containing copper smelting wastewater, and obtaining an iron powder replacement turbid liquid after sufficient reaction; adding a first pH value regulator to the iron powder replacement turbid liquid, adjusting the pH value and adding an oxidant, and obtaining an iron removal turbid liquid after sufficient reaction; adding a flocculant to the iron removal turbid liquid, and after sufficient flocculation, obtaining an iron removal underflow and an iron removal overflow through solid-liquid separation; performing filter press dehydration treatment on the iron removal underflow to obtain gold-copper slag and a filtrate; mixing the iron removal overflow and the filtrate, and adding a second pH value regulator, adjusting the pH value and fully reacting to obtain a neutralized turbid liquid. Through the above-mentioned method, the present application effectively recovers valuable substances while avoiding the impact of harmful metal ions in wastewater on the production system or ecological environment, and no hazardous waste is generated in the whole process, achieving the unity of environmental benefits and economic benefits.

[0073] It should be noted that the present application is not limited to the above-mentioned embodiments. The above-mentioned embodiments are only examples, and the embodiments having the same structure as the technical idea and exerting the same effect within the scope of the technical solution of the present application are all included in the technical scope of the present application. In addition, without departing from the scope of the main purpose of the present application, various modifications that can be thought of by those skilled in the art to the embodiments and other methods of combining some of the 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 and copper smelting wastewater, in g / L; α is the reaction coefficient, ranging from 1.0 to 1.1; S2. adding a first pH value adjusting agent to the iron powder replacement turbid liquid, adding an oxidant after adjusting the pH value, and obtaining an iron removal turbid liquid after sufficient reaction; adding a flocculant to the iron removal turbid liquid, and obtaining an iron removal underflow and an iron removal overflow after sufficient flocculation by solid-liquid separation; performing filter press dehydration treatment on the iron removal underflow to obtain gold-copper slag and a filtrate; S3. The iron removal overflow and the filtrate are mixed, and a second pH adjuster is added to fully react after adjusting the pH value 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, 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.

3. 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.

4. 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 used to adjust the pH value of the iron powder-substituted turbid liquid to 3.7-5.0; the first pH adjuster is one or more of lime, sodium hydroxide, and sodium bicarbonate.

5. 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.

6. 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.

7. 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 .

8. 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%.

9. The comprehensive treatment method for gold-containing copper smelting wastewater according to claim 1, characterized in that: In step S3, the second pH adjuster is used to adjust the pH value to 7.0-7.9, and the second pH adjuster is lime or carbide slag.

10. 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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