Recovery system for valuable elements in multi-metal arsenic acid wastewater

Abstract

The utility model relates to a recovery system for valuable elements in multi-metal arsenic acid wastewater, which comprises a 1 # wastewater pool, the 1 # wastewater pool is connected to a mixed precipitation stirring barrel through a delivery pump, and the mixed precipitation stirring barrel is sequentially connected to a 1 # thickener and a 1 # filter press through delivery pumps; an overflow port of the 1 # thickener and a filtrate port of the 1 # filter press are connected to a 2 # wastewater pool, the 2 # wastewater pool is connected to an iron removal stirring barrel, and the iron removal stirring barrel is sequentially connected to the 4 # thickener and the 4 # filter press through a delivery pump; an overflow port of the 4 # thickener and a filtrate port of the 4 # filter press are connected to a 3 # wastewater pool, the 3 # wastewater pool is connected to a gypsum preparation stirring barrel, and the gypsum preparation stirring barrel is sequentially connected to the 5 # thickener and the 5 # filter press through a delivery pump. According to the device disclosed by the utility model, by combining five parts of equipment, namely mixed precipitation, purification and iron removal, gypsum preparation, two-stage arsenic removal and arsenic solidification treatment, comprehensive recovery and innocent treatment of valuable elements in acid wastewater are realized, and high-quality gold-silver-copper concentrate, high-quality gypsum and dischargeable purified water are obtained.

Description

Technical Field

[0001] This utility model belongs to the field of hydrometallurgical technology, specifically relating to a system for recovering valuable elements from polymetallic arsenic acidic wastewater. Background Technology

[0002] Non-ferrous metal smelting enterprises generate large amounts of acidic wastewater containing polymetallic arsenic during production. This type of acidic wastewater is complex in nature, and its composition often varies significantly depending on the production process. Generally, arsenic in the acidic wastewater is treated by wet precipitation to produce gypsum slag, or by sulfidation precipitation to obtain arsenic filter cake. However, valuable metals in this type of wastewater are not recovered. With the development and utilization of mineral resources and the continuous rise in international gold prices, the recovery of valuable metals such as gold, silver, and copper from wastewater is attracting increasing attention. In particular, wastewater generated from the washing or acid leaching of roasting slag from gold-containing polymetallic sulfide ores has high value for recovering valuable elements. In this type of wastewater, gold and silver exist in the form of fine particles, while copper, arsenic, and iron exist in ionic form. Due to these different forms, it is difficult to achieve comprehensive and effective recovery of valuable metals.

[0003] The main sedimentation and recovery methods for this type of wastewater include lime-iron salt method and sulfidation method. Valuable metals and harmful elements in the precipitate are recovered and their hazards are reduced by hydrometallurgy, pyrometallurgy and flotation. However, these methods have some shortcomings and defects in application. Either the valuable components cannot be effectively recovered, or secondary pollution is generated again, which has a serious impact on the natural environment. (1) Lime method: The product of lime hydrolysis, calcium hydroxide, reacts with arsenate to form calcium arsenate precipitate. In order to improve the arsenic removal effect, the pH value is generally controlled at 9 to 10.5. Under this environment, other valuable metals are easy to form co-precipitates, producing a large amount of sludge. The recovery rate of valuable metals is low, and the post-treatment cost is high. (2) Iron salt method: Iron ions are used to generate a large amount of iron hydroxide colloidal particles under the condition of pH value 3 to 5.4, thereby adsorbing and co-precipitating arsenate ions. Valuable components will also be co-precipitated in this method and cannot be effectively recovered. (3) Sulfidation flotation method: Using Sulfide agents precipitate valuable metal ions and then recover them by flotation. The flotation tailings or tailings are then treated. This method will cause the arsenic in the waste liquid to be sulfide-floated into the product, resulting in unqualified products. In addition, the flotation of fine particles has poor foaming effect and low recovery rate. Furthermore, the process is long and the investment is large, which affects the economic benefits of enterprises. (4) Pyrometallurgical smelting: Pyrometallurgical smelting removes arsenic and recovers valuable metals. The process is complex, costly, and causes serious secondary environmental pollution. (5) Cyanide leaching: Cyanide reacts with gold and silver to form soluble complexes, allowing gold and silver to enter the solution, thereby realizing the extraction of gold and silver. This method requires the use of highly toxic cyanide, which not only has high reagent costs and low gold and silver leaching rates, but also makes it difficult to recover copper. Moreover, the cyanide residue produced also faces the problem of secondary environmental pollution.

[0004] In order to overcome the shortcomings and defects of the existing technology, this utility model provides a system for recovering valuable elements from polymetallic arsenic acid wastewater, so as to recover valuable metals from arsenic acid wastewater in an economical and environmentally friendly manner. Utility Model Content

[0005] This invention provides a system for recovering valuable elements from polymetallic arsenic-containing acidic wastewater. The method targets gold-containing polymetallic arsenic-containing acidic wastewater. Sodium hydrosulfide is added to precipitate copper and arsenic ions. After the reaction is complete, a small amount of 25# black reagent is added to enhance the hydrophobicity of fine gold and silver particles, causing them to co-precipitate with copper and arsenic. The filtered acidic mother liquor undergoes iron removal (generating ferric hydroxide) to prepare high-purity gypsum. The precipitate undergoes two-stage leaching to remove arsenic, yielding gold, silver, and copper concentrate and arsenic-containing mother liquor. The arsenic-containing mother liquor is then sequentially treated with ferric hydroxide and lime for arsenic removal and purification, thus achieving the goal of harmless treatment of acidic wastewater and comprehensive recovery of valuable elements. The technical solution includes:

[0006] The specific technical solution of this utility model is: a recovery system for valuable elements in polymetallic arsenic acidic wastewater, comprising a wastewater tank #1, which is connected to a mixing sedimentation tank via a transfer pump. The mixing sedimentation tank is sequentially connected to a thickener #1 and a filter press #1 via a transfer pump. The overflow port of the thickener #1 and the filtrate port of the filter press #1 are connected to a wastewater tank #2. The wastewater tank #2 is connected to an iron removal mixing tank, which is sequentially connected to a thickener #4 and a filter press #4 via a transfer pump. The overflow port of the thickener #4 and the filtrate port of the filter press #4 are connected to a wastewater tank #3, which is connected to a gypsum production mixing tank. The gypsum production mixing tank is connected to a... The feed pump is connected in sequence to thickener #5 and filter press #5; the filter cake inlet of filter press #1 is connected to the primary arsenic removal mixing tank, which is connected in sequence to thickener #2 and filter press #2 via a feed pump; the filter cake inlet of filter press #2 is connected to the secondary arsenic removal mixing tank, which is connected in sequence to thickener #3 and filter press #3 via a feed pump; the overflow port of thickener #2 and the filtrate port of filter press #2, as well as the overflow port of thickener #3 and the filtrate port of filter press #3, are connected to wastewater tank #4; the wastewater tank #4 and the filter cake inlet of filter press #4 are connected to solid arsenic mixing tank, which is connected in sequence to thickener #6 and filter press #6 via a feed pump.

[0007] Furthermore, preferably, there are multiple primary arsenic removal mixing tanks, and adjacent primary arsenic removal mixing tanks are connected by a transfer pump.

[0008] Furthermore, preferably, there are multiple secondary arsenic removal mixing tanks, and adjacent secondary arsenic removal mixing tanks are connected by a transfer pump.

[0009] The beneficial effects of this utility model are as follows: The system described in this utility model combines five parts: mixing and sedimentation, iron removal purification, gypsum preparation, two-stage arsenic removal, and arsenic solidification treatment. This combination enables the comprehensive recovery and harmless treatment of valuable elements in acidic wastewater, ultimately yielding high-quality gold, silver, and copper concentrates, high-quality gypsum, and purified water that can be discharged. This fully maximizes the value of resources, and the treated wastewater meets industrial wastewater discharge standards, which helps reduce environmental pollution risks and has good economic and environmental benefits. Attached Figure Description

[0010] Figure 1 This is a diagram showing the equipment association of a system for recovering valuable elements from polymetallic arsenic-acidic wastewater according to this utility model.

[0011] In the diagram: 1-1# wastewater tank, 2-mixing sedimentation tank, 3-1# thickener, 4-1# filter press, 5-primary arsenic removal mixing tank, 6-2# wastewater tank, 7-2# thickener, 8-2# filter press, 9-secondary arsenic removal mixing tank, 10-3# thickener, 11-3# filter press, 12-iron removal mixing tank, 13-4# thickener, 14-4# filter press, 15-gypsum preparation mixing tank, 16-5# thickener, 17-5# filter press, 18-arsenic fixation mixing tank, 19-6# thickener, 20-6# filter press, 21-3# wastewater tank, 22-4# wastewater tank. Detailed Implementation

[0012] To make the technical problems and solutions solved by this utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely for explaining the present utility model and are not intended to limit the present utility model.

[0013] In the description of this utility model, it should be understood that the terms "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0014] In the description of this utility model, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," and "connect" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0015] like Figure 1 As shown, a system for recovering valuable elements from polymetallic arsenic-acidic wastewater includes a wastewater tank 1 (1#), which is connected to a mixing and settling tank 2 via a transfer pump. The mixing and settling tank 2 is then connected to a thickener 3 (1#) and a filter press 4 (1#) via a transfer pump. The overflow port of the thickener 3 and the filtrate port of the filter press 4 (1#) are connected to a wastewater tank 6 (2#), which is connected to an iron removal mixing tank 12. The iron removal mixing tank 12 is then connected to a thickener 13 (4#) and a filter press 14 (4#) via a transfer pump. The filter cake port of the filter press 14 is connected to an arsenic-fixing mixing tank 18, which is then connected to a thickener 6 (6#) via a transfer pump. Thickener 19 and filter press 20 (No. 6); the filter cake port of filter press 4 (No. 1) is connected to the primary arsenic removal mixing tank 5, which is connected in sequence to thickener 7 (No. 2) and filter press 8 (No. 2) via a transfer pump; the filter cake port of filter press 8 (No. 2) is connected to the secondary arsenic removal mixing tank 9, which is connected in sequence to thickener 10 (No. 3) and filter press 11 (No. 3) via a transfer pump; the overflow port of thickener 13 (No. 4) and the filtrate port of filter press 14 (No. 4) are connected to wastewater tank 21 (No. 3), which is connected to gypsum mixing tank 15, which is connected in sequence to thickener 16 (No. 5) and filter press 17 (No. 5) via a transfer pump.

[0016] There are multiple primary arsenic removal mixing tanks 5 and / or secondary arsenic removal mixing tanks 9, and adjacent primary arsenic removal mixing tanks and / or secondary arsenic removal mixing tanks are connected by a transfer pump.

[0017] The above system is used to recover valuable elements from this polymetallic arsenic acidic wastewater. The specific working principle is as follows:

[0018] The multi-metallic arsenic acidic wastewater stored in wastewater tank 1 is pumped to the mixing sedimentation stirring tank 2, and sodium hydrosulfide solution and No. 25 black reagent are added in sequence. The mixture is stirred and reacted to fully precipitate the copper and arsenic ions and fine gold and silver particles in the wastewater. Then, it is filtered by thickener 3 and filter press 4 to obtain mixed precipitate residue of copper, arsenic, gold and silver and acidic mother liquor.

[0019] The acidic mother liquor is transferred to wastewater tank 6 (No. 2), then to iron removal stirring tank 12, where air and sodium hydroxide solution are introduced and stirred to react. After the reaction is completed, the mixture is thickened and filtered by thickener 13 (No. 4) and filter press 14 (No. 4) to obtain ferric hydroxide and iron removal mother liquor.

[0020] The iron removal mother liquor is transferred to wastewater tank 21 (No. 3), then to gypsum mixing tank 15, and then lime slurry is added and stirred to react. After the reaction is completed, it is thickened and filtered by thickener 16 (No. 5) and filter press 17 (No. 5) to obtain high-quality gypsum and purified water that can be discharged.

[0021] The mixed precipitate of copper, arsenic, gold and silver is transferred to the primary arsenic removal stirring tank 5, and a certain amount of acidic wastewater containing polymetallic arsenic is added or copper sulfate is added at the same time for primary leaching arsenic removal. After leaching, it is thickened and filtered by thickener 7 and filter press 8 to obtain gold and silver precipitate and arsenic-containing acidic mother liquor I.

[0022] The gold and silver precipitate from the first-stage leaching for arsenic removal is then transferred to the second-stage arsenic removal mixing tank 9. A certain amount of acidic wastewater containing polymetallic arsenic is added, or copper sulfate is added simultaneously for the second-stage leaching for arsenic removal. After leaching, the precipitate is thickened and filtered by thickener 10 and filter press 11 to obtain high-quality gold, silver and copper concentrate and acidic mother liquor II containing arsenic.

[0023] Finally, the arsenic-containing acidic mother liquors I and II were combined and transferred to wastewater tank 22 (No. 4), then to arsenic-fixing mixing tank 18. Ferric hydroxide filtered by filter press 14 (No. 4) was added to arsenic-fixing mixing tank 18 and stirred for a period of time. Then, lime slurry was added and stirred for further reaction. After the reaction was completed, the mixture was thickened and filtered by thickener 19 (No. 6) and filter press 20 (No. 6) to obtain arsenic-containing slag and purified water that can be discharged.

[0024] Thus, through the combination of five parts—mixing and sedimentation, iron removal purification, gypsum preparation, two-stage arsenic removal, and arsenic solidification—this system achieves comprehensive recovery and harmless treatment of valuable elements in acidic wastewater, ultimately yielding high-quality gold, silver, and copper concentrates, high-quality gypsum, and purified water that can be discharged. This fully maximizes the value of resources, and the treated wastewater meets industrial wastewater discharge standards, which helps reduce environmental pollution risks and has good economic and environmental benefits.

[0025] Application Example 1:

[0026] Raw material 1#: A type of acidic wastewater containing polymetallic arsenic, with a solution pH of 1.8 and metal element content of: arsenic 512 mg / L, copper 1650 mg / L, gold 0.15 mg / L, silver 0.048 mg / L, and iron 4700 mg / L.

[0027] like Figure 1 As shown, this invention is used to recover valuable elements from polymetallic arsenic acidic wastewater. The specific treatment process is as follows:

[0028] (1) Detection of metal element content: Take a certain amount of acidic wastewater containing polymetallic arsenic to be treated and determine the contents of copper, arsenic, gold, silver and iron respectively;

[0029] (2) Mixed precipitation of copper, arsenic, gold and silver: The polymetallic arsenic acidic wastewater was pumped into the mixed precipitation stirring tank 2, and 20% sodium hydrosulfide solution was added to it and stirred to precipitate copper and arsenic ions. After stirring for 15 minutes, 10g / m³ of 25# black powder was added. 3 The stirring time is 2-4 minutes to enhance the hydrophobicity of the fine gold and silver particles, causing them to co-precipitate with copper and arsenic. The mixture is then concentrated and filtered through thickener 3 (No. 1) and filter press 4 (No. 1) to obtain a mixed precipitate containing copper, arsenic, gold, and silver, and an acidic mother liquor. Sodium hydrosulfide is added according to the chemical reaction equation Cu... 2+ +S 2- =CuS and 2H3AsO3+3S 2- +6H + =As2S3↓+6H2O should be added at 1.2 to 1.4 times the theoretical cumulative amount.

[0030] (3) Purification and iron removal of acidic mother liquor: The acidic mother liquor is transferred into the iron removal stirring tank 12. After stirring with air for 5 to 10 minutes, 10% sodium hydroxide solution is added. The pH value is controlled at 3 to 4. The stirring reaction time is 10 to 20 minutes. Then, it is thickened and filtered by thickener 13 and filter press 14 to obtain iron hydroxide and iron removal mother liquor.

[0031] (4) Preparation of high-quality gypsum: The iron removal mother liquor is transferred into the gypsum mixing tank 15, 10% lime milk is added, the pH value is controlled at 7-7.5, and the mixture is stirred and reacted for 15 minutes. Then it is thickened and filtered by a No. 5 thickener 16 and a No. 5 filter press 17 to obtain high-quality gypsum and purified water that can be discharged.

[0032] (5) Two-stage leaching of harmful element arsenic:

[0033] Primary leaching for arsenic removal: The mixed precipitate of copper, arsenic, gold, and silver is transferred to the primary arsenic removal stirring tank 5. A certain amount of acidic wastewater containing polymetallic arsenic is added, or copper sulfate is added simultaneously for primary leaching for arsenic removal. The amount of polymetallic wastewater or copper sulfate added is determined according to the chemical reaction equation 3Cu 2+ The theoretically calculated amount of copper is 0.8 to 0.9 times that of CuS + 3As2S3 + 6H2O = 3CuS + 3H3AsO4 + 3SO2. The solid-liquid ratio of the leaching solution is 1:1 to 1:9, and the leaching time is 1.5 to 2 hours. Then, the solution is thickened and filtered through a #2 thickener 7 and a #2 filter press 8 to obtain gold and silver precipitate and arsenic-containing acidic mother liquor I.

[0034] Secondary leaching for arsenic removal: The gold and silver precipitate from the primary leaching for arsenic removal is transferred to the secondary arsenic removal stirring tank 9. A certain amount of acidic wastewater containing polymetallic arsenic is added, or copper sulfate is added simultaneously for secondary leaching for arsenic removal. The amount of polymetallic wastewater or copper sulfate added is based on the chemical reaction equation 3Cu 2+ The copper content is increased by 0.2 to 0.3 times according to the theoretical calculation of +3As2S3+6H2O=3CuS+3H3AsO4+3SO2, and the copper concentration in the solution is controlled to be 2 to 3 times that of the copper concentration in the first-stage leaching solution. The leaching time is 0.5 to 1 hour. Then, the solution is thickened and filtered by thickener 10 and filter press 11 to obtain high-quality gold, silver and copper concentrate and arsenic-containing acidic mother liquor II.

[0035] (6) Arsenic solidification treatment: After arsenic-containing acidic mother liquor I and II are combined and transferred into arsenic solidification mixing tank 18, ferric hydroxide filtered by filter press 4#14 is added to arsenic solidification mixing tank 18. After stirring for 10 to 15 minutes, 10% lime milk is added, the pH value is controlled at 7 to 7.5, and the stirring reaction time is 10 to 15 minutes. Then, it is thickened and filtered by thickener 6#19 and filter press 6#20 to obtain arsenic-containing slag and purified water that can be discharged.

[0036] The test results were as follows: the gold grade was 27.64 g / t, the silver grade was 9.75 g / t, and the copper grade was 40.85%, with gold, silver, and copper recovery rates of 77.99%, 78.25%, and 95.38%, respectively.

[0037] Application Example 2:

[0038] Raw material 2#: A type of acidic wastewater containing polymetallic arsenic, with a solution pH of 2.2 and metal element content of: arsenic 486 mg / L, copper 1130 mg / L, gold 0.18 mg / L, silver 0.075 mg / L, and iron 5100 mg / L.

[0039] The processing procedure described in Application Example 1 was applied to raw material #2, and the test results were as follows: the gold grade was 26.89 g / t, the silver grade was 10.25 g / t, and the copper grade was 38.96%, with gold, silver, and copper recovery rates of 78.30%, 77.19%, and 94.92%, respectively.

[0040] As can be seen from the above application examples, the system described in this utility model can comprehensively recover valuable elements such as gold, silver, and copper from acidic wastewater containing multiple metals. The gold recovery rate can reach about 78%, the silver recovery rate can reach about 78%, and the copper recovery rate can reach about 95%, truly realizing comprehensive resource utilization. At the same time, the intermediate product ferric hydroxide can be used to treat the wastewater for arsenic removal, ensuring that this type of acidic wastewater meets the discharge standards, truly achieving harmless treatment, reducing the risk of environmental pollution, and having good economic and environmental benefits.

[0041] The present invention has been described in detail above through specific and preferred embodiments. However, those skilled in the art should understand that the present invention is not limited to the embodiments described above. Any modifications or equivalent substitutions made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A system for recovering valuable elements from polymetallic arsenic-acidic wastewater, characterized in that, The system includes a wastewater tank (1) #1, which is connected to a mixing sedimentation tank (2) via a pump. The mixing sedimentation tank (2) is connected to a thickener (3) and a filter press (4) via a pump. The overflow port of the thickener (3) and the filtrate port of the filter press (4) are connected to a wastewater tank (6) #2. The wastewater tank (6) is connected to an iron removal mixing tank (12), which is connected to a thickener (13) and a filter press (14) via a pump. The overflow port of the thickener (13) and the filtrate port of the filter press (14) are connected to a wastewater tank (21) #3. The wastewater tank (21) is connected to a pre-made gypsum mixing tank (15), which is connected to a thickener (16) and a filter press (17) via a pump. 7); The filter cake inlet of the No. 1 filter press (4) is connected to the primary arsenic removal mixing tank (5), the primary arsenic removal mixing tank (5) is connected in sequence to the No. 2 thickener (7) and the No. 2 filter press (8) via a transfer pump, the filter cake inlet of the No. 2 filter press (8) is connected to the secondary arsenic removal mixing tank (9), the secondary arsenic removal mixing tank (9) is connected in sequence to the No. 3 thickener (10) and the No. 3 filter press (11) via a transfer pump; the 2 The overflow port of the #thickener (7) and the filtrate port of the #2 filter press (8), as well as the overflow port of the #3 thickener (10) and the filtrate port of the #3 filter press (11), are connected to the #4 wastewater tank (22). The #4 wastewater tank (22) and the filter residue port of the #4 filter press (14) are connected to the solid arsenic mixing tank (18). The solid arsenic mixing tank (18) is connected to the #6 thickener (19) and the #6 filter press (20) in sequence via a transfer pump.

2. The system for recovering valuable elements from polymetallic arsenic-acidic wastewater according to claim 1, characterized in that: There are multiple primary arsenic removal mixing tanks (5), and adjacent primary arsenic removal mixing tanks are connected by a transfer pump.

3. A system for recovering valuable elements from polymetallic arsenic-acidic wastewater according to claim 1 or 2, characterized in that: There are multiple secondary arsenic removal mixing tanks (9), and adjacent secondary arsenic removal mixing tanks are connected by a transfer pump.

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