Comprehensive treatment method for copper flotation tailings and copper-containing acidic wastewater

Abstract

The method for comprehensive treatment of copper flotation tailings and copper-containing acidic wastewater specifically includes pre-classification + coarse particle dehydration, copper flotation tailings are stirred and slurried, then cyclone classification, and the coarse particles on the screen are transported to the outer area of ​​the yard for storage; fine particle alum stone flotation, adding carbonic acid, sodium silicate and composite flotation agent TC-12, alum stone flotation concentrate is slurried and then filtered to obtain alum stone concentrate filter cake; fine particle size + neutralization slag mixed concentration filter press, the obtained mixed filter press filter cake is transported to the yard for storage; pre-neutralization iron precipitation, adding lime to the acidic wastewater for pre-neutralization and iron removal, adding PAM to flocculate iron precipitation; iron slag Re-neutralization: add lime to re-neutralize the pre-neutralized sludge; for copper sulfide precipitation, add sodium hydrosulfide to cause sulfidation reaction of the pre-neutralized precipitation effluent, accurately control the ORP potential, add PAM for flocculation and copper precipitation, and filter press the sulfide slag to obtain H2S gas, acid mist and sulfide slag filter cake; for controlled neutralization, add lime to the reflux mud and the re-neutralized iron slag to prepare the slurry, react with the sulfide precipitation effluent, add PAM for flocculation and precipitation, and neutralize the acidic wastewater and the pre-neutralized precipitation effluent. It has the advantages of efficient and comprehensive treatment, and unified economic, social and environmental benefits.

Description

Technical Field

[0001] The invention relates to the technical field of underground mining, and in particular to a method for comprehensively treating copper flotation tailings and copper-containing acidic wastewater. Background Art

[0002] Copper ore is one of the most important metal mineral resources. Flotation is the most commonly used beneficiation method for copper ore. The flotation process generates a large amount of waste tailings. The accumulation of copper tailings occupies a large area, causing environmental pollution and easily leading to tailings dam failures, posing safety risks. Furthermore, copper tailings are rich in non-metallic resources. The comprehensive recovery or utilization of useful components in copper tailings is essential for developing a circular economy and achieving the goal of "turning waste into treasure." Furthermore, copper mines generate large amounts of copper-containing acidic wastewater during mining and production, causing significant damage to the surrounding ecological environment. This wastewater must be promptly treated for recycling or discharged in a manner that meets standards. For example, a particularly large copper mine produces nearly 20 million tons of copper flotation tailings annually. The main non-metallic minerals in this tailings are quartz, alunite, and dickite, with alunite being the most valuable for comprehensive recovery. Currently, existing tailings ponds in mines are insufficiently stocked, making it difficult to obtain approvals and construction for new ones on schedule. This creates a serious challenge for the continuity of these ponds. At the same time, with the continuous increase in the catchment area of ​​the mining site spoil dump and the area of ​​the copper stockpile, the amount and concentration of copper-containing acidic water in the mining area are also increasing year by year. At present, the copper-containing acidic water is treated by extensively adding liquid alkali along the waterway. Not only can the copper not be recovered, but the amount of liquid alkali added is difficult to control. When the water quality fluctuates greatly, the treatment is even more ineffective. If the conventional lime neutralization method is used, not only the lime consumption is large, but also the generated heavy metal hydroxide-alum floc has a small specific gravity and slow sedimentation rate. It often overflows with the water flow during the sedimentation and separation process, and the water quality after treatment is difficult to stably meet the standards. Moreover, the neutralization slag is filtered separately. Due to the high content of fine particles in the feed, the filter mesh is easily clogged, resulting in high moisture content of the filter cake, thin cake, poor air permeability, and serious impact on the efficiency of the filter press. The large amount of neutralization slag generated needs to be stored and treated separately, which also puts great pressure on the mine environment and safety.

[0003] Therefore, it is of great significance to develop a comprehensive method for the treatment of copper flotation tailings and copper-containing acidic wastewater. It can not only coordinate technical solutions, comprehensive treatment and synergistic efficiency, but also relieve worries and difficulties for enterprises, and at the same time is conducive to the development of circular economy and the promotion of environmental governance. Summary of the Invention

[0004] The task of the present invention is to overcome the deficiencies of the prior art and provide a method for comprehensively treating copper flotation tailings and copper-containing acidic wastewater, which can achieve both efficient and comprehensive treatment and achieve the three-in-one economic, social and environmental benefits.

[0005] The task of the present invention is accomplished by the following technical solutions:

[0006] A method for comprehensively treating copper flotation tailings and copper-containing acidic wastewater. The mineral processing and water treatment reagent components include conventional reagents such as sodium carbonate, sodium silicate, lime, PAM, sodium hydrosulfide, and a self-made composite flotation reagent TC-12. The composite flotation reagent TC-12 is prepared by uniformly mixing oxidized paraffin soap and diethyl diisobutylmalonate in a mass ratio of 1:1. The specific process steps and conditions are as follows:

[0007] a. Pre-classification + coarse fraction dehydration: After passing through the agitation and slurry mixing tank, the copper flotation tailings are classified by a hydrocyclone at a concentration of 47.30-49.80%. The underflow of the hydrocyclone is dehydrated by a high-frequency dehydration screen to obtain a coarse fraction of +0.074mm above the sieve and a fine fraction of -0.074mm below the sieve. The coarse fraction of +0.074mm above the sieve with a moisture content of 20.64-21.18% and an operating yield of 48.80-51.24% is transported as coarse tailings to the storage area outside the yard;

[0008] b. Fine-grained alunite flotation: A loop process consisting of one roughing, one scavenging, and two cleaning processes is used to flotate the cyclone overflow. Based on the dry weight of each ton of copper flotation tailings, 1800-1875 g / t of carbonic acid, 300-360 g / t of sodium silicate, and 60-66 g / t of composite flotation reagent TC-12 are added to the roughing mixing tank. No reagents are added during the cleaning and scavenging processes. The alunite flotation concentrate is filtered after passing through the mixing tank to obtain an alunite concentrate filter cake product with a moisture content of 21.0%-22.0%.

[0009] c. Fine particle size + neutralization residue mixed concentration and filter press: The overflow of the hydrocyclone after alum stone flotation is concentrated together with the bottom sludge of the controlled neutralization sedimentation tank in a high-efficiency thickener. The bottom sludge of the high-efficiency thickener is stirred in a slurry mixing tank and then mixed and filtered to obtain a mixed filter cake with a moisture content of 19.45-20.30%. The mixed sludge is then transported to the storage area of ​​the yard for storage;

[0010] d. Pre-neutralization and iron precipitation: After homogenizing and averaging the acidic wastewater containing 300-496 mg / L copper in the regulating buffer tank, add 18.05-18.40 kg / m3 of lime to the pre-neutralization reaction tank. 3 Carry out pre-neutralization and iron removal reaction, control the pH value of the reaction water at 2.78-2.86, and add PAM⑤6.5-6.8g / m 3 Carry out flocculation and iron precipitation;

[0011] e. Iron slag re-neutralization: Add lime 3.72-3.95 kg / m3 into the iron slag re-neutralization tank. 3 Re-neutralize the sludge in the pre-neutralization sedimentation tank;

[0012] f. Sulfide copper precipitation: add sodium hydrosulfide⑥ 0.78~0.79kg / m 3The effluent from the pre-neutralization sedimentation tank is subjected to sulfidation reaction. The ORP potential of the sulfidation reaction is precisely controlled at 213-229mV. The effluent from the sulfidation reaction is placed in the sulfidation sedimentation tank and PAM 6.5-6.8g / m is added. 3 The copper is precipitated by flocculation, and the bottom mud of the sulfide sedimentation tank is filtered by sulfide slag to obtain H2S gas and acid mist and sulfide slag filter cake with a moisture content of 30.0-31.0%, which is the copper sulfide product;

[0013] g. Control neutralization: add lime in the neutralization slurry mixing tank at a rate of 3.72-3.95 kg / m 3 The slurry is prepared with the return mud and the re-neutralized iron slag, and the neutralization reaction is carried out together with the effluent from the sulfide sedimentation tank in the control neutralization reaction tank. The pH value of the reaction effluent is controlled at 7.23-7.66. The amount of PAM added in the control neutralization sedimentation tank is 8.0-8.2g / m 3 The flocculation and sedimentation are carried out, and the acidic wastewater containing Cu < 300 mg / L and the effluent from the pre-neutralization sedimentation tank are directly fed into the neutralization reaction tank without sulfidation and copper precipitation.

[0014] Compared with the prior art, the present invention has the following advantages or effects:

[0015] (1) Pre-classification, coarse-grained dehydration and fine-grained filtration of copper flotation tailings facilitate storage in outer coarse and inner fine-grained areas, enhance drainage and reverse filtration effects, improve drainage and consolidation strength, and reduce safety hazards.

[0016] (2) The high-efficiency flotation agent TC-12 is suitable for recovering fine-grained alunite. The SO3 content of the alunite concentrate obtained is >24%, and the SO3 recovery rate is >90%, which is significantly better than that of conventional agents.

[0017] (3) The multi-point neutralization and batch dosing method used in pre-neutralization, iron slag re-neutralization and controlled neutralization improves the lime utilization rate and reduces the lime consumption per unit volume of copper-containing acidic wastewater by more than 15% compared with conventional processes.

[0018] (4) Precisely control the redox potential. Under specific redox potential conditions, the copper sulfide precipitation reaction is complete and the copper recovery rate is above 98%.

[0019] (5) Fine-grained tailings and neutralized slag are mixed and filtered to improve the particle size composition of the feed, effectively improve the filter pressing efficiency, and can increase the equipment efficiency by more than 17%.

[0020] (6) The treated water is first used for production reuse, and the remaining amount is discharged stably and in compliance with the standards, taking into account both the production water demand and the water balance problem.

[0021] (7) There is no need to build a separate neutralization slag storage, which saves space and corresponding investment and reduces the risk of secondary pollution.

[0022] PAM in the application documents refers to polyacrylamide. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 The figure is a schematic diagram of a method for comprehensive treatment of copper flotation tailings and copper-containing acidic wastewater proposed in the present invention.

[0024] The symbols in the accompanying drawings represent:

[0025] ⑴ Cyclone underflow ⑵ Cyclone overflow ⑶ Coarse particle size on the sieve ⑷ Fine particle size under the sieve ⑸ Alum stone concentrate filter cake ⑹ Alum stone concentrate filtrate ⑺ Pre-neutralization sedimentation tank sludge ⑻ Pre-neutralization sedimentation tank effluent ⑼ Sulfide sedimentation tank sludge ⑽ Sulfide sedimentation tank effluent ⑾ Controlled neutralization sedimentation tank sludge ⑿ Controlled neutralization sedimentation tank effluent ⒀ Sulfide slag filtrate ⒁ Sulfide slag filter cake ⒂ Mixed filter press filter cake ⒃ Mixed filter press filtrate ⒄ H2S gas and acid mist ⒅ High-efficiency thickener sludge ⒆ High-efficiency thickener effluent ① Sodium carbonate ② Sodium silicate ③ TC-12 ④ Lime ⑤ PAM ⑥ Sodium hydrosulfide

[0026] The present invention is described in further detail below with reference to the accompanying drawings. DETAILED DESCRIPTION

[0027] like Figure 1 As shown, a method for comprehensively treating copper flotation tailings and copper-containing acidic wastewater is provided. The mineral processing and water treatment reagent components include conventional reagents sodium carbonate ①, sodium silicate ②, lime ④, PAM ⑤, sodium hydrosulfide ⑥, and a homemade composite flotation reagent TC-12 ③; the composite flotation reagent TC-12 ③ is prepared by uniformly mixing oxidized paraffin soap and diethyl diisobutylmalonate in a mass ratio of 1:1. The specific process steps and conditions are as follows:

[0028] a. Pre-classification + coarse particle dewatering: The copper flotation tailings are subjected to cyclone classification at a concentration of 47.30-49.80% after being stirred and slurried in a slurry mixing tank. The cyclone bottom flow (1) is dewatered on a high-frequency dewatering screen to obtain a coarse particle size of +0.074 mm on the sieve (3) and a fine particle size of -0.074 mm under the sieve (4). The coarse particle size of +0.074 mm on the sieve (3) with a moisture content of 20.64-21.18% and an operating yield of 48.80-51.24% is transported to the outer area of ​​the stockpile as coarse tailings;

[0029] b. Fine-grained alunite flotation: A loop process of one roughing, one scavenging and two selections is used to flotate the cyclone overflow (2). According to the dry weight of each ton of copper flotation tailings, sodium carbonate ①1800~1875g / t, sodium silicate ②300~360g / t and composite flotation agent TC-12③60~66g / t are added to the roughing stirring and slurrying tank. No reagents are added to all selection and scavenging. The alunite flotation concentrate is filtered after the stirring and slurrying tank to obtain a filter cake (5) with a moisture content of 21.0%~22.0% of the alunite concentrate;

[0030] c. Fine particle size (4) + neutralization residue mixed concentration filter press: The overflow of the hydrocyclone after flotation of alum stone (2) and the control neutralization sedimentation tank sludge (11) are concentrated together in a high-efficiency thickener, and the high-efficiency thickener sludge (18) is mixed and filtered after stirring the slurry tank to obtain a mixed filter cake (15) with a moisture content of 19.45~20.30% and a mixed slag, which is transported to the storage area in the yard;

[0031] d. Pre-neutralization and iron precipitation: After homogenizing and averaging the acidic wastewater containing 300-496 mg / L copper in the regulating buffer tank, add lime④18.05-18.40 kg / m 3 Carry out pre-neutralization and iron removal reaction, control the pH value of the reaction water at 2.78-2.86, and add PAM⑤6.5-6.8g / m 3 Carry out flocculation and iron precipitation;

[0032] e. Iron slag re-neutralization: Add lime④3.72~3.95kg / m3 in the iron slag re-neutralization tank 3 Re-neutralizing the pre-neutralized sedimentation tank sludge (7);

[0033] f. Sulfide copper precipitation: add sodium hydrosulfide⑥ 0.78~0.79kg / m 3 The effluent from the pre-neutralization sedimentation tank (8) was subjected to a sulfidation reaction. The ORP potential of the sulfidation reaction was precisely controlled at 213-229 mV. The effluent from the sulfidation reaction was added with PAM⑤6.5-6.8 g / m 3 Flocculation and copper precipitation are carried out, and the bottom mud of the sulfide precipitation tank (9) is subjected to sulfide slag pressure filtration to obtain H2S gas and acid mist (17) and sulfide slag filter cake (14) with a moisture content of 30.0-31.0%, namely copper sulfide product;

[0034] g. Control neutralization: add lime into the neutralization slurry mixing tank④, dosage 3.72~3.95kg / m 3 The slurry is prepared with the return mud and the re-neutralized iron slag, and the neutralization reaction is carried out together with the effluent of the sulfide sedimentation tank (10) in the control neutralization reaction tank. The pH value of the reaction effluent is controlled at 7.23-7.66. PAM⑤ is added in the control neutralization sedimentation tank at a dosage of 8.0-8.2 g / m 3 The flocculation and precipitation are carried out, and the acid wastewater containing Cu < 300 mg / L and the effluent from the pre-neutralization sedimentation tank (8) are directly fed into the neutralization reaction tank without sulfidation and copper precipitation.

[0035] The process of the present invention may further be:

[0036] The -0.074 mm undersize fine particle size (4) obtained from the pre-classification and coarse particle size dehydration in step a is returned to the cyclone to form a closed loop.

[0037] In the step f, the sulfidation reaction tank for copper precipitation is subjected to closed ventilation, and the H2S gas and acid mist (17) are absorbed by alkaline solution in the acid mist purification tower and then discharged.

[0038] In step g, the neutralized and refluxed portion is controlled to be mixed, concentrated and filtered with the overflow of the cyclone after the alum stone is reselected (2).

[0039] The alunite concentrate filtrate (6), mixed filter press filtrate (16), sulfide slag filtrate (13), controlled neutralization sedimentation tank effluent (12), and high-efficiency thickener effluent (19) are collected in a clear water tank and returned to the production system for use, and the remaining amount is discharged stably and meets the standards.

[0040] In step g, the bottom mud (11) of the control neutralization sedimentation tank with a flow ratio of 8.4-9.0% is returned to the neutralization mud mixing tank.

[0041] The embodiments and comparative examples of the present invention are based on a large copper mine that uses a flotation + heap leaching process to process ore. The flotation system produces nearly 20 million tons of tailings each year. As the drainage area of ​​the spoil dump and the copper storage area continue to increase, the amount and concentration of copper-containing acidic water in the mining area are also increasing year by year. The following experiments were conducted on the copper flotation tailings and copper-containing acidic wastewater in the mining area:

[0042] Example 1

[0043] After passing through the mixing tank, the copper flotation tailings are classified in a hydrocyclone at a concentration of 47.30%. The underflow from the hydrocyclone is dewatered on a high-frequency dewatering screen. The coarse fraction above the +0.074mm sieve has a moisture content of 21.26%, resulting in an operating yield of 51.24%. This fraction is then transferred to an off-site stockpile as coarse tailings. The fine fraction below the -0.074mm sieve returns to the hydrocyclone, forming a closed-circuit process. The hydrocyclone overflow is subjected to alunite flotation using a loop process consisting of a roughing, a scavenging, and two cleaning steps. Based on the dry weight of the copper flotation tailings, 1800g / t of sodium carbonate, 300g / t of sodium silicate, and 60g / t of TC-12 are added to the roughing mixing tank. No chemicals are added during the cleaning and scavenging steps. The alunite flotation concentrate is filtered after the mixing tank. The filter cake of the alunite concentrate has a moisture content of 21.0% and is stored as alunite product for sale. After the alum stone is selected, the cyclone overflow and the controlled neutralization sedimentation tank sludge excluding the return flow are concentrated in the high-efficiency thickener. The high-efficiency thickener bottom flow passes through the mixing slurry tank and then undergoes mixed filter pressing. The mixed filter cake has a moisture content of 20.30% and is transported to the storage area as mixed slag. After the copper-containing acidic wastewater raw liquid is homogenized and weighed in the regulating buffer tank, 18.05kg / m3 of lime is added to the pre-neutralization reaction tank. 3 Carry out pre-neutralization and iron removal reaction, the pH value of the reaction water is controlled at 2.78, and PAM is added in the pre-neutralization sedimentation tank at a dosage of 6.5g / m 3The sludge in the pre-neutralization sedimentation tank is then flocculated and the amount of lime added to the iron slag re-neutralization tank is 3.72 kg / m 3 Re-neutralize. Add sodium hydrosulfide at a dosage of 0.78 kg / m in the sulfidation reaction tank. 3 The effluent from the pre-neutralization sedimentation tank was subjected to sulfidation reaction. The ORP potential of the sulfidation reaction was controlled at 223.0 mV. The effluent from the sulfidation reaction was added with PAM at a dosage of 6.5 g / m3 in the sulfidation sedimentation tank. 3 Copper is precipitated by flocculation, and the bottom mud of the sulfide sedimentation tank is filtered by sulfide slag. The moisture content of the sulfide slag filter cake is 30.0%, which is sold as copper sulfide product. The sulfide reaction tank is closed and ventilated. H2S gas and acid mist are absorbed by alkaline solution in the acid mist purification tower before being discharged. Lime is added at a rate of 3.72kg / m3 in the neutralization slurry mixing tank. 3 The slurry is prepared with the return mud and the re-neutralized iron slag, and the neutralization reaction is carried out together with the effluent from the sulfide sedimentation tank in the control neutralization reaction tank. The pH value of the reaction effluent is controlled at 7.23. The dosage of PAM is 8.0g / m 3 Flocculation and sedimentation are performed, and the bottom mud of the controlled neutralization sedimentation tank, which accounts for 8.4% of the flow rate, is returned to the neutralization mud mixing tank. Except for the return flow, it is mixed with the overflow of the hydrocyclone after the reselection of alum stone for concentration and pressure filtration. The alum stone concentrate filtrate, mixed pressure filtrate, sulfide slag filtrate, and the effluent from the controlled neutralization sedimentation tank and high-efficiency thickener are concentrated in the clear water tank and returned to the production system for use. The remaining amount meets the standards and is discharged externally.

[0044] Example 2

[0045] After passing through the mixing tank, the copper flotation tailings are classified in a hydrocyclone at a concentration of 48.50%. The underflow from the hydrocyclone is dewatered on a high-frequency dewatering screen. The coarse fraction above the +0.074mm sieve has a moisture content of 21.18%, resulting in an operating yield of 49.70%. This fraction is then transferred to an off-site stockpile as coarse tailings. The fine fraction below the -0.074mm sieve returns to the hydrocyclone, forming a closed-circuit system. The hydrocyclone overflow is subjected to alumite flotation using a single roughing, a single scavenging, and a double cleaning circuit. Based on the dry weight of the copper flotation tailings, 1825g / t of sodium carbonate, 320g / t of sodium silicate, and 62g / t of TC-12 are added to the roughing mixing tank. No chemicals are added during the cleaning and scavenging processes. The alumite flotation concentrate is filtered after the mixing tank. The filter cake of the alumite concentrate has a moisture content of 21.5% and is stored and sold as alumite product. After the alum stone is selected, the cyclone overflow and the controlled neutralization sedimentation tank sludge excluding the return flow are concentrated in the high-efficiency thickener. The high-efficiency thickener bottom flow passes through the mixing slurry tank and then undergoes mixed filter pressing. The mixed filter cake has a moisture content of 19.50% and is transported to the storage area as mixed slag. After the copper-containing acidic wastewater raw liquid is homogenized and weighed in the regulating buffer tank, 18.40 kg / m3 of lime is added to the pre-neutralization reaction tank. 3Carry out pre-neutralization and iron removal reaction, the pH value of the reaction water is controlled at 2.86, and PAM is added in the pre-neutralization sedimentation tank at a dosage of 6.6g / m 3 The sludge in the pre-neutralization sedimentation tank is then added to the iron slag re-neutralization tank at a rate of 3.84 kg / m 3 Re-neutralize. Add sodium hydrosulfide at a dosage of 0.79 kg / m in the sulfidation reaction tank. 3 The effluent from the pre-neutralization sedimentation tank was subjected to sulfidation reaction. The ORP potential of the sulfidation reaction was controlled at 213.0 mV. The effluent from the sulfidation reaction was added with PAM at a dosage of 6.6 g / m 3 Copper is flocculated and precipitated, and the sludge from the sulfide sedimentation tank is filtered through sulfide slag. The sulfide slag filter cake has a moisture content of 30.5% and is sold as copper sulfide. The sulfide reaction tank is enclosed and vented, and H2S gas and acid mist are absorbed by alkaline solution in the acid mist purification tower before being discharged. 3.84 kg / m3 of lime is added to the neutralization slurry mixing tank to mix the reflux slurry and the re-neutralized iron slag. This slurry is then neutralized with the effluent from the sulfide sedimentation tank in the controlled neutralization reaction tank. The pH value of the reaction effluent is controlled at 7.43. 8.1 g / m3 of PAM is added to the controlled neutralization sedimentation tank for flocculation and precipitation. 8.6% of the sludge from the controlled neutralization sedimentation tank is returned to the neutralization slurry mixing tank. Except for the reflux portion, it is mixed with the overflow from the cyclone after the re-selection of alum stone for concentration and pressure filtration. Alunite concentrate filtrate, mixed filter press filtrate, sulfide slag filtrate, controlled neutralization sedimentation tank effluent, and high-efficiency thickener effluent are concentrated into the clear water tank and returned to the production system for use, and the remaining amount meets the standards and is discharged externally.

[0046] Example 3

[0047] After passing through a mixing tank, the copper flotation tailings are classified in a hydrocyclone at a concentration of 49.80%. The underflow from the hydrocyclone is dewatered on a high-frequency dewatering screen. The coarse fraction above the +0.074mm sieve has a moisture content of 20.64%, resulting in an operating yield of 48.80%. This fraction is then transferred to an off-site stockpile as coarse tailings. The fine fraction below the -0.074mm sieve returns to the hydrocyclone, forming a closed-circuit system. The hydrocyclone overflow is subjected to alumite flotation using a single roughing, a single scavenging, and a double cleaning circuit. Based on the dry weight of the copper flotation tailings, 1850g / t of sodium carbonate, 340g / t of sodium silicate, and 64g / t of TC-12 are added to the roughing mixing tank. No chemicals are added during the cleaning and scavenging processes. The alumite flotation concentrate is slurried in the mixing tank and then filtered. The filter cake of the alumite concentrate has a moisture content of 21.7% and is stored and sold as alumite product. After the alum stone is selected, the cyclone overflow and the controlled neutralization sedimentation tank sludge excluding the return flow are concentrated in the high-efficiency thickener. The high-efficiency thickener bottom flow passes through the mixing slurry tank and then undergoes mixed filter pressing. The mixed filter cake has a moisture content of 19.45% and is transported to the storage area as mixed slag. After the copper-containing acidic wastewater raw liquid is homogenized and weighed in the regulating buffer tank, 18.39 kg / m3 of lime is added to the pre-neutralization reaction tank.3 Pre-neutralization and iron removal reaction was carried out, and the pH value of the reaction water was controlled at 2.81. PAM was added in the pre-neutralization sedimentation tank at a dosage of 6.7 g / m 3 The sludge in the pre-neutralization sedimentation tank is then added to the iron slag re-neutralization tank at a rate of 3.95 kg / m 3 Re-neutralize. Add sodium hydrosulfide at a dosage of 0.79 kg / m in the sulfidation reaction tank. 3 The effluent from the pre-neutralization sedimentation tank was subjected to sulfidation reaction. The ORP potential of the sulfidation reaction was controlled at 229.0 mV. The effluent from the sulfidation reaction was added with PAM at a dosage of 6.7 g / m3 in the sulfidation sedimentation tank. 3 Copper is precipitated by flocculation, and the bottom mud of the sulfide sedimentation tank is filtered through sulfide slag. The moisture content of the sulfide slag filter cake is 31.0%, which is sold as copper sulfide product. The sulfide reaction tank is enclosed for ventilation, and H2S gas and acid mist are absorbed by alkaline solution in the acid mist purification tower before being discharged. Lime is added at a rate of 3.95kg / m3 in the neutralization slurry mixing tank. 3 The slurry is prepared with the return mud and the re-neutralized iron slag, and the neutralization reaction is carried out together with the effluent from the sulfide sedimentation tank in the control neutralization reaction tank. The pH value of the reaction effluent is controlled at 7.66. The dosage of PAM is 8.2g / m 3 Flocculation and sedimentation are performed, and the bottom mud of the controlled neutralization sedimentation tank, which accounts for 8.8% of the flow rate, is returned to the neutralization mud mixing tank. Except for the return flow, it is mixed with the overflow of the hydrocyclone after the reselection of alum stone for concentration and pressure filtration. The alum stone concentrate filtrate, mixed pressure filtrate, sulfide slag filtrate, and the effluent from the controlled neutralization sedimentation tank and high-efficiency thickener are concentrated in the clear water tank and returned to the production system for use. The remaining amount meets the standards and is discharged externally.

[0048] Example 4

[0049] After passing through the mixing tank, the copper flotation tailings are classified in a hydrocyclone at a concentration of 49.55%. The underflow from the hydrocyclone is dewatered on a high-frequency dewatering screen. The coarse fraction above the +0.074mm sieve has a moisture content of 20.90%, resulting in an operating yield of 49.0%. This fraction is then transferred to an off-site stockpile as coarse tailings. The fine fraction below the -0.074mm sieve returns to the hydrocyclone in a closed circuit. The hydrocyclone overflow is subjected to alunite flotation using a single roughing, a single scavenging, and a double cleaning circuit. Based on the dry weight of the copper flotation tailings, 1875g / t of sodium carbonate, 360g / t of sodium silicate, and 66g / t of TC-12 are added to the roughing mixing tank. No chemicals are added during the cleaning and scavenging processes. The alunite flotation concentrate is filtered after the mixing tank. The filter cake of the alunite concentrate has a moisture content of 22.0% and is stored as alunite product for sale. After the alum stone is selected, the cyclone overflow and the controlled neutralization sedimentation tank sludge excluding the return flow are concentrated in the high-efficiency thickener. The high-efficiency thickener bottom flow passes through the mixing slurry tank and then undergoes mixed filter pressing. The mixed filter cake has a moisture content of 19.70% and is transported to the storage area as mixed slag. After the copper-containing acidic wastewater raw liquid is homogenized and weighed in the regulating buffer tank, 18.29 kg / m3 of lime is added to the pre-neutralization reaction tank. 3 Carry out pre-neutralization and iron removal reaction, the pH value of the reaction water is controlled at 2.80, and PAM is added in the pre-neutralization sedimentation tank at a dosage of 6.8g / m 3 The sludge in the pre-neutralization sedimentation tank is then flocculated and the amount of lime added to the iron slag re-neutralization tank is 3.88 kg / m 3 Re-neutralize. Add lime at a rate of 3.88 kg / m3 into the neutralized slurry mixing tank. 3 The slurry is mixed with the return slurry and re-neutralized iron slag, and then neutralized with the effluent from the pre-neutralization sedimentation tank in a controlled neutralization reaction tank. The pH of the reaction effluent is controlled at 7.46. PAM is added to the controlled neutralization sedimentation tank at a dosage of 8.2 g / m³ for flocculation and precipitation. The bottom sludge from the controlled neutralization sedimentation tank, which accounts for 9.0% of the flow rate, is returned to the neutralization slurry mixing tank. Except for the return flow, it is mixed with the overflow from the hydrocyclone after the alum stone reselection for concentration and filter pressing. The alum stone concentrate filtrate, mixed filter press filtrate, effluent from the controlled neutralization sedimentation tank, and effluent from the high-efficiency thickener are collected in a clear water tank and returned to the production system for use. The remaining amount meets the standards and is discharged externally.

[0050] Comparative Example 1

[0051] Only alunite flotation was compared, and the flotation objects and other processes, conditions, and indicators were exactly the same as in Example 3. For the cyclone overflow in Example 3, alunite flotation was carried out using a single roughing, a single scavenging, and two cleaning circuits. Based on the dry weight of the copper flotation tailings, 1920 g / t of sodium carbonate, 360 g / t of sodium silicate, and 84 g / t of oxidized paraffin soap were added to the roughing agitation tank. No reagents were added during the cleaning and scavenging processes. The reagent dosages in Comparative Example 1 were all the optimal dosages determined through screening.

[0052] Comparative Example 2

[0053] Only the neutralization effect is compared. The water treatment object is exactly the same as that in Example 3. For the copper-containing copper acid wastewater stock solution in Example 3, after homogenization and equalization, the conventional neutralization method is adopted. All the lime dosage is added in the neutralization reaction tank at one time for neutralization reaction. The pH value of the reaction water is controlled at 7.50. The total amount of lime added is 31kg / m 3 .

[0054] Table 1 Chemical composition and particle size distribution characteristics of copper flotation tailings

[0055]

[0056] Table 2 Main components of copper-containing acidic wastewater

[0057]

[0058] Table 3 Coarse particle dehydration, fine particle mixed filtration and flotation alum stone indicators

[0059]

[0060]

[0061] Table 4 Process indicators for the treatment of copper-containing acidic wastewater in the whole process

[0062]

[0063]

[0064] The chemical composition and particle size distribution characteristics of the copper flotation tailings and the water quality characteristics of the copper-containing acidic wastewater targeted by Examples 1 to 4 of the present invention and Comparative Examples 1 to 2 are shown in Tables 1 and 2, and the specific implementation results are shown in Tables 3 and 4. In Examples 1 to 4, the copper flotation tailings were graded and dehydrated. When the feed concentration was 47.30%, 48.50%, 49.80% and 49.55%, the moisture content of the coarse particle size on the screen was 21.16%, 21.18%, 20.64% and 20.90%, the yield on the screen was 51.24%, 49.70%, 48.80% and 49.00%, and the moisture content of the fine particle size + neutralized slag mixed filter cake was 20.30%, 19.50%, 19.45% and 19.70%, which is conducive to dry storage in the outer coarse and inner fine particle areas. The 630 experimental single-chamber feed filter press is used to filter the mixture, the separate neutralization slag and the separate fine particle size. The unit processing capacity is 0.083t / m 2 h, 0.021t / m 2 h and 0.071t / m 2 h, the former is 3.95 times and 1.17 times the latter two. Using the efficient collector TC-12 for flotation of the fine-grained fraction, the SO3 contents of the alunite concentrate obtained were 25.79%, 24.94%, 24.99%, and 24.77%, and the SO3 recovery rates were 90.17%, 91.14%, 90.86%, and 90.90%. Similarly, for the fine-grained fraction of Example 3, the alunite concentrate obtained in Comparative Example 1 using a conventional collector had a SO3 content of 22.23% and a SO3 recovery rate of 87.41%. The indicators obtained with TC-12 were significantly better. The pH values ​​of the raw solutions treated in Examples 1 to 3 were 1.77, 1.77 and 1.74, the copper contents were 300 mg / L, 414 mg / L and 496 mg / L, the iron contents were 5310 mg / L, 5290 mg / L and 5380 mg / L, and the total lime dosage for pre-neutralization, controlled neutralization and iron slag re-neutralization was 25.49 kg / m3, 26.08 kg / m 3 and 26.29kg / m 3 After treatment, the pH values ​​were 7.23, 7.43 and 7.66; the ORP potential of copper sulfide precipitation was controlled at 223mV, 213mV and 229mV, and the dosage of sodium hydrosulfide was 0.78kg / m 3 , 0.79kg / m 3 and 0.79kg / m 3 The recovery rates of copper in the liquid were 98.35%, 99.18% and 99.22%. The pH value of the raw liquid treated in Example 4 was 1.77, the copper content was 287mg / L, the iron content was 5160mg / L, and the total lime dosage for pre-neutralization, controlled neutralization and iron slag re-neutralization was 26.05kg / m 3, the pH value after treatment is 7.46. Similarly, for the raw liquid treated in Example 3, the total amount of lime added in Comparative Example 2 using conventional neutralization method is 31kg / m 3 The total lime dosage of Example 3 is reduced by 15.26%. It can be seen that the present invention has outstanding advantages over the traditional method in terms of the reuse and safe and low-cost treatment of copper flotation tailings and copper-containing acidic wastewater.

[0065] As described above, the present invention can be better implemented. The above embodiments are only the best implementation methods of the present invention, but the implementation methods of the present invention are not limited to the above embodiments. Other changes, modifications, replacements, combinations, and simplifications made without departing from the spirit and principles of the present invention should be considered equivalent replacement methods and are included in the scope of protection of the present invention.

Claims

1. A method for comprehensive treatment of copper flotation tailings and copper-containing acidic wastewater, characterized in that The mineral processing and water treatment reagent components include conventional reagents such as sodium carbonate, sodium silicate, lime, PAM, sodium hydrosulfide, and a self-made composite flotation reagent TC-12; the composite flotation reagent TC-12 is prepared by uniformly mixing oxidized paraffin soap and diethyl diisobutylmalonate in a mass ratio of 1:

1. The specific process steps and conditions are as follows: a. Pre-classification + coarse particle dewatering: copper flotation tailings are subjected to cyclone classification at a concentration of 47.30-49.80% after being stirred and slurried in a slurry tank. The cyclone bottom flow (1) is dewatered on a high-frequency dewatering screen to obtain a coarse particle size of +0.074 mm on the sieve (3) and a fine particle size of -0.074 mm under the sieve (4). The coarse particle size of +0.074 mm on the sieve (3) with a moisture content of 20.64-21.18% and an operating yield of 48.80-51.24% is transported to the outer area of ​​the stockpile as coarse tailings; b. Fine-grained alunite flotation: A loop process of one roughing, one scavenging and two cleaning processes is used to flotate the cyclone overflow (2). Based on the dry weight of each ton of copper flotation tailings, 1800-1875 g / t of sodium carbonate, 300-360 g / t of sodium silicate and 60-66 g / t of composite flotation reagent TC-12 are added to the roughing stirring and slurrying tank. No reagents are added in all cleaning and scavenging processes. The alunite flotation concentrate is filtered after passing through the stirring and slurrying tank to obtain an alunite concentrate filter cake (5) with a moisture content of 21.0-22.0%. c. Mixed concentration and filtration of the undersize fine particle size (4) + neutralization residue: The overflow of the hydrocyclone (2) after the flotation of alum stone is concentrated together with the bottom mud of the control neutralization sedimentation tank (11) in a high-efficiency thickener. The bottom mud of the high-efficiency thickener (18) is mixed and filtered after being stirred in a slurry mixing tank to obtain a mixed filter cake (15) with a moisture content of 19.45-20.30% and a mixed residue, which is then transported to the inner area of ​​the yard for storage; d. Pre-neutralization and iron precipitation: After homogenizing and averaging the acidic wastewater containing 300-496 mg / L copper in the regulating buffer tank, add 18.05-18.40 kg / m3 of lime to the pre-neutralization reaction tank. 3 Carry out pre-neutralization and iron removal reaction, control the pH value of the reaction water at 2.78-2.86, and add PAM6.5-6.8g / m3 in the pre-neutralization sedimentation tank. 3 Carry out flocculation and iron precipitation; e. Iron slag re-neutralization: Add lime 3.72-3.95 kg / m3 into the iron slag re-neutralization tank. 3 Re-neutralization of the pre-neutralization sedimentation tank sludge (7); f. Sulfide copper precipitation: add sodium hydrosulfide 0.78-0.79 kg / m3 into the sulfide reaction tank 3 The effluent from the pre-neutralization sedimentation tank (8) was subjected to a sulfidation reaction. The ORP potential of the sulfidation reaction was precisely controlled at 213-229 mV. The effluent from the sulfidation reaction was placed in a sulfidation sedimentation tank and PAM 6.5-6.8 g / m was added. 3 The copper is precipitated by flocculation, and the bottom mud (9) of the sulfide sedimentation tank is subjected to sulfide slag filter pressing to obtain H2S gas and acid mist (17) and sulfide slag filter cake (14) with a moisture content of 30.0-31.0%, which is the copper sulfide product; g. Control neutralization: add lime in the neutralization slurry mixing tank at a rate of 3.72-3.95 kg / m 3 The slurry is prepared with the return mud and the re-neutralized iron slag, and the neutralization reaction is carried out together with the effluent from the sulfide sedimentation tank (10) in the control neutralization reaction tank. The pH value of the reaction effluent is controlled at 7.23-7.

66. The amount of PAM added in the control neutralization sedimentation tank is 8.0-8.2 g / m 3 The flocculation and sedimentation are carried out, and the acid wastewater containing Cu < 300 mg / L and the effluent from the pre-neutralization sedimentation tank (8) are directly fed into the controlled neutralization reaction tank without sulfidation copper precipitation.

2. The method according to claim 1, wherein The -0.074 mm undersize fine particle size (4) obtained from the pre-classification and coarse particle size dehydration in step a is returned to the hydrocyclone to form a closed loop.

3. The method according to claim 1, wherein In the step f, the sulfidation reaction tank for copper precipitation is closed and ventilated, and the H2S gas and acid mist (17) are absorbed by the alkaline solution in the acid mist purification tower and then discharged.

4. The method according to claim 1, wherein In step g, the neutralized and refluxed portion is controlled to be mixed, concentrated and filtered with the overflow of the cyclone after the alum stone is reselected (2).

5. The method according to claim 1, wherein The alunite concentrate filtrate (6), mixed filter press filtrate (16), sulfide slag filtrate (13), controlled neutralization sedimentation tank effluent (12), and high-efficiency thickener effluent (19) are collected in a clear water tank and returned to the production system for use, and the remaining amount is discharged in a stable and standard manner.

6. The method according to claim 1, wherein In step g, the neutralization sedimentation tank sludge (11) is controlled to return to the neutralization sludge mixing tank at a flow rate ratio of 8.4 to 9.0%.

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