Method for synergistically bio-oxidizing pretreatment of resourceful electroplating sludge

Abstract

The application discloses a method for pretreating resourceful electroplating sludge by synergic biological oxidation, and belongs to the field of mineral processing engineering. The method for pretreating resourceful electroplating sludge by synergic biological oxidation is provided, the method is combined with the synergic biological oxidation pretreatment technology, valuable metal elements in the electroplating sludge are effectively recovered, and the process comprises five steps of slurry treatment, synergic treatment, filtration, ion exchange process and desorption. The method has the advantages of remarkable resourceful effect, friendly operation environment, high production efficiency and the like, and realizes the goal of "waste treatment by waste".

Description

Technical Field

[0001] This invention belongs to the field of mineral processing engineering, and specifically relates to a method for synergistic biological oxidation pretreatment of resource-based electroplating sludge. Background Technology

[0002] Electroplating sludge is a sediment formed after treating electroplating wastewater. It is mainly composed of hydroxides and carbonates of metals such as copper and zinc, and is characterized by high water content, high thermal stability of heavy metal components, and easy migration, making it highly susceptible to secondary pollution and classified as hazardous waste. To address the pH reduction of biological oxidation solutions, CaO is often added for neutralization on-site. Without further treatment, the biological oxidation solution will not meet or even hinder on-site production, becoming waste liquid. The properties of electroplating sludge vary depending on the electroplating plant's production and treatment processes, posing challenges to its harmless treatment and comprehensive utilization. In recent years, domestic and international efforts in treating electroplating sludge have focused on the following aspects: 1. Solidification and stabilization technology, such as patent CN03126608.8 "Methods for Comprehensive Utilization, Stabilization, and Solidification Treatment of Electroplating Sludge from Industrial Waste Residue"; 2. Acid leaching, such as patent CN202110504703.8 "A Method for Resource Recovery of High-Content Copper and Nickel Electroplating Sludge"; 3. Ammonia leaching, such as patent CN20211. 1175147.0 "System and process for recovering copper, nickel, zinc, chromium and iron from electroplating sludge or other polymetallic mixtures" 4. Bioleaching method, such as patent CN202310639330.4 "A method for bioleaching heavy metals from electroplating sludge based on electro-chemical enhancement" 5. Smelting method, such as patent CN202310993004.3 "A method for recovering valuable metals from electroplating sludge" 6. Preparation of ceramic materials, such as patent CN201610417252.3 "Ceramic aggregate from electroplating sludge and its manufacturing method".

[0003] Electroplating sludge can be divided into two main categories: mixed sludge and separate sludge. Traditional solidification and stabilization technologies, such as those used for preparing ceramic materials, can dispose of a considerable amount of electroplating sludge and eliminate material pollution problems. However, they do not fully utilize the valuable elements in the sludge, resulting in insignificant resource utilization. Acid leaching and ammonia leaching are typical technologies for recovering valuable metals from electroplating sludge, but they consume large amounts of acid or ammonia and operate in an unfriendly environment. Smelting methods use coal and coke as fuel and reducing agents to recover valuable elements, but they generate significant carbon emissions, and the smelting furnace temperature is often above 1000℃, resulting in a harsh operating environment.

[0004] Biological oxidation pretreatment is used for refractory gold ores. It utilizes microorganisms such as *Thiobacillus ferrooxidans* to oxidize components such as pyrite and arsenopyrite that encapsulate gold under acidic conditions, thereby exposing the gold. Most biological oxidation reactions are acid-producing processes, which leads to a decrease in the pH of the solution, generally between 1.2 and 1.8. However, the optimal pH for bacterial growth is 1.8 to 2.5. Obviously, the biological oxidation liquid environment is not conducive to bacterial growth and metabolism, and ultimately affects the gold extraction efficiency. Summary of the Invention

[0005] To address the problems existing in the background technology, the present invention provides a method for synergistic biological oxidation pretreatment of resource-based electroplating sludge. This method combines the biological oxidation liquid from the biological oxidation process of refractory gold ore with electroplating sludge. The acidic biological oxidation liquid can be used as a leachate for acid leaching of electroplating sludge, effectively utilizing the valuable metal elements in the electroplating sludge. Furthermore, the copper and zinc hydroxides and carbonates in the electroplating sludge can effectively neutralize the pH of the oxidation liquid, enhance bacterial activity, and improve the production efficiency of biological oxidation pretreatment, truly achieving "waste treatment with waste".

[0006] This invention provides a method for synergistic biological oxidation pretreatment of resource-based electroplating sludge, the specific steps of which are as follows:

[0007] Step 1, Slurry Processing: Slurry processing refers to the operation of adding solvent to solid particles and mixing them thoroughly. This operation can further disperse electroplating sludge. Electroplating sludge and water are fed into a slurry machine for slurry processing.

[0008] Step Two: Co-processing: This step involves co-processing with biological oxidation pretreatment to extract valuable metal elements from electroplating sludge. Furthermore, electroplating sludge mainly contains alkaline oxides of valuable metal elements, which can act as neutralizing agents for the biological oxidation solution. The slurry-treated electroplating sludge is fed into the biological oxidation solution, which is a leachate produced during the biological oxidation of acidic refractory gold ore. The mixture reacts to obtain the co-processed product.

[0009] Step 3, Filtration: The co-processed product obtained in Step 2 is subjected to solid-liquid separation to obtain filtrate and filter residue respectively; the filtrate contains valuable metal elements from electroplating sludge, and the filter residue contains refractory gold ore treated by bacteria in the biological oxidation liquid and suspended solids that are insoluble in acid.

[0010] Step 4, Ion exchange process: Use ion exchange resin to exchange the valuable elements in the filtrate obtained in Step 3; feed the filtrate obtained in Step 3 into the cation exchange resin from top to bottom, and the valuable metal ions in the filtrate will be adsorbed into the cation exchange resin.

[0011] Step 5, Desorption: Treat the cation exchange resin with an acid solution to obtain a enriched solution containing copper and zinc ions.

[0012] Furthermore, in step one, the ratio of electroplating sludge to water is (1~1.8):1 by mass, and the stirring speed during slurry treatment is 300~500 r / min.

[0013] Furthermore, in step two, the valuable element is selected from one or more of copper and zinc.

[0014] Furthermore, in step two, the ratio of electroplating sludge after pulping treatment to biological oxidation liquid is 1:(2~3) by volume; the co-treatment temperature is 25~30℃, and the co-treatment time is 15~20h.

[0015] Furthermore, in step four, during the ion exchange process, the filtrate height is always higher than the cation exchange resin layer. When the effluent concentration of the cation exchange resin reaches the flow point, the filtrate feeding is stopped, and the ion exchange ends.

[0016] Furthermore, in step five, the acid solution is selected from inorganic acids, specifically including hydrochloric acid, sulfuric acid, and nitric acid, with a concentration of 5% to 20% by mass.

[0017] The beneficial effects of this invention are:

[0018] Advantage 1 of the present invention is that: the synergistic biological oxidation pretreatment process treats electroplating sludge and recovers valuable elements such as copper and zinc, thereby realizing resource utilization.

[0019] The second advantage of this invention is that the oxidation liquid generated during the biological oxidation pretreatment process is acidic, with a pH between 1.2 and 1.8. This environment is not conducive to the growth and reproduction of bacteria, which in turn affects the gold extraction efficiency. Adding electroplating sludge can neutralize the pH of the oxidation liquid, promote the gold extraction efficiency, and realize "using waste to produce waste". Attached Figure Description

[0020] Figure 1 A schematic diagram of a method for pretreatment of resource-based electroplating sludge using synergistic biological oxidation. Detailed Implementation

[0021] Combination Figure 1 This invention provides a clear and complete description of the technical solutions implemented in this patent. It should be noted that the examples described in this invention are for further explanation and illustration only, and are not intended to limit its scope of application. All other examples obtained by those skilled in the art based on this invention without inventive effort are within the protection scope of this patent.

[0022] Example 1

[0023] The electroplating sludge in this example is Cu-plated sludge, and its properties are shown in Table 1.

[0024] Table 1. Composition of the electroplating sludge using Cu as the plating agent in Example 1.

[0025] element Ca Fe Ni Cu Zn Sn content / % 6.0 10.0 2.0 25.0 6.0 4.0

[0026] according to Figure 1 Perform the steps shown:

[0027] Step 1: Pulping treatment: Electroplating sludge and water are mixed at a mass ratio of 1:1 and fed into a pulping machine for stirring at a stirring speed of 300 r / min.

[0028] Step 2: Co-processing: The electroplating sludge after pulping is fed into the biological oxidation liquid at a volume ratio of 1:3 and mixed for 15 hours.

[0029] Step 3 Filtration: Solid-liquid separation is performed on the co-processed product to obtain filtrate and filter residue. The filtrate is fed into the next step of ion exchange, and the filter residue is fed into the subsequent gold extraction operation.

[0030] Step 4: Ion exchange process: The filtrate flows through the exchange column for ion exchange. During the process, the filtrate is always higher than the cation exchange column until the effluent reaches the flow point.

[0031] Step 5: Desorption: The ion exchange column was treated with 20% hydrochloric acid to obtain a copper-rich solution. The copper content was determined to be 75%.

[0032] Example 2

[0033] The electroplating sludge used in Example 2 is the same as that in Example 1, and the following steps are performed:

[0034] Step 1: Pulping treatment: Electroplating sludge and water are fed into a pulping machine at a mass ratio of 1.2:1 and stirred at a stirring speed of 300 r / min.

[0035] Step 2: Co-processing: The electroplating sludge after pulping is fed into the biological oxidation liquid at a volume ratio of 1:3 and mixed for 15 hours.

[0036] Step 3 Filtration: Solid-liquid separation is performed on the co-processed product to obtain filtrate and filter residue. The filtrate is fed into the next step of ion exchange, and the filter residue is fed into the subsequent gold extraction operation.

[0037] Step 4: Ion exchange process: The filtrate flows through the exchange column for ion exchange. During the process, the filtrate is always higher than the cation exchange column until the effluent reaches the flow point.

[0038] Step 5: Desorption: The ion exchange column was treated with 20% hydrochloric acid to obtain a copper-rich solution. The copper content was determined to be 75%.

[0039] Example 3

[0040] The electroplating sludge used in Example 3 is the same as that in Example 1, and the following steps are performed:

[0041] Step 1: Pulping treatment: Electroplating sludge and water are mixed in a mass ratio of 1.2:1 into a pulping machine and stirred at a stirring speed of 350 r / min.

[0042] Step 2: Co-processing: The electroplating sludge after pulping is fed into the biological oxidation liquid at a volume ratio of 1:3 and mixed for 15 hours.

[0043] Step 3 Filtration: Solid-liquid separation is performed on the co-processed product to obtain filtrate and filter residue. The filtrate is fed into the next step of ion exchange, and the filter residue is fed into the subsequent gold extraction operation.

[0044] Step 4: Ion exchange process: The filtrate flows through the exchange column for ion exchange. During the process, the filtrate is always higher than the cation exchange column until the effluent reaches the flow point.

[0045] Step 5: Desorption: The ion exchange column was treated with 20% hydrochloric acid to obtain a copper-enriched solution.

[0046] The final enriched solution contained 73% copper.

[0047] Example 4:

[0048] The electroplating sludge used in Example 4 is the same as that in Example 1, and the following steps are performed:

[0049] Step 1: Pulping treatment: Electroplating sludge and water are fed into a pulping machine at a mass ratio of 1.2:1 and stirred at a stirring speed of 300 r / min.

[0050] Step 2: Co-processing: The electroplating sludge after pulping is fed into the biological oxidation liquid at a volume ratio of 1:3 and mixed for 18 hours.

[0051] Step 3 Filtration: Solid-liquid separation is performed on the co-processed product to obtain filtrate and filter residue. The filtrate is fed into the next step of ion exchange, and the filter residue is fed into the subsequent gold extraction operation.

[0052] Step 4: Ion exchange process: The filtrate flows through the exchange column for ion exchange. During the process, the filtrate is always higher than the cation exchange column until the effluent reaches the flow point.

[0053] Step 5: Desorption: The ion exchange column was treated with 20% hydrochloric acid to obtain a copper-rich solution. The copper content was determined to be 75%.

[0054] Example 5:

[0055] The electroplating sludge in Example 5 is a Zn-plating sludge with an Fe content of 45.97%, a Zn content of 17.33%, and a Sn content of 8.42%. Figure 1 Perform as shown:

[0056] Step 1: Pulping treatment: Electroplating sludge and water are mixed in a mass ratio of 1:1 and fed into a pulping machine for stirring at a stirring speed of 300 r / min.

[0057] Step 2: Co-processing: The electroplating sludge after pulping is fed into the biological oxidation liquid at a volume ratio of 1:3 and mixed for 15 hours.

[0058] Step 3 Filtration: Solid-liquid separation is performed on the co-processed product to obtain filtrate and filter residue. The filtrate is fed into the next step of ion exchange, and the filter residue is fed into the subsequent gold extraction operation.

[0059] Step 4: Ion exchange process: The filtrate flows through the exchange column for ion exchange. During the process, the filtrate is always higher than the cation exchange column until the effluent reaches the flow point.

[0060] Step 5: Desorption: The ion exchange column was treated with 20% hydrochloric acid to obtain a zinc-enriched solution. The zinc content was found to be 47%.

[0061] Example 6

[0062] The composition of the electroplating sludge in Example 6 is the same as that in Example 5, according to... Figure 1 The method shown is used to process:

[0063] Step 1: Pulping treatment: Electroplating sludge and water are fed into a pulping machine at a mass ratio of 1.2:1 and stirred at a stirring speed of 300 r / min.

[0064] Step 2: Co-processing: The electroplating sludge after pulping is fed into the biological oxidation liquid at a volume ratio of 1:3 and mixed for 15 hours.

[0065] Step 3 Filtration: Solid-liquid separation is performed on the co-processed product to obtain filtrate and filter residue. The filtrate is fed into the next step of ion exchange, and the filter residue is fed into the subsequent gold extraction operation.

[0066] Step 4: Ion exchange process: The filtrate flows through the exchange column for ion exchange. During the process, the filtrate is always higher than the cation exchange column until the effluent reaches the flow point.

[0067] Step 5: Desorption: The ion exchange column was treated with 20% hydrochloric acid to obtain a zinc-enriched solution. The zinc content was found to be 43%.

[0068] Example 7

[0069] The composition of the electroplating sludge in Example 7 is the same as that in Example 5, according to... Figure 1 The method shown is used to process:

[0070] Step 1: Pulping treatment: Electroplating sludge and water are mixed in a mass ratio of 1:1 and fed into a pulping machine for stirring at a stirring speed of 350 r / min.

[0071] Step 2: Co-processing: The electroplating sludge after pulping is fed into the biological oxidation liquid at a volume ratio of 1:3 and mixed for 15 hours.

[0072] Step 3 Filtration: Solid-liquid separation is performed on the co-processed product to obtain filtrate and filter residue. The filtrate is fed into the next step of ion exchange, and the filter residue is fed into the subsequent gold extraction operation.

[0073] Step 4: Ion exchange process: The filtrate flows through the exchange column for ion exchange. During the process, the filtrate is always higher than the cation exchange column until the effluent reaches the flow point.

[0074] Step 5: Desorption: The ion exchange column was treated with 20% hydrochloric acid to obtain a zinc-enriched solution. The zinc content was found to be 45%.

[0075] Example 8

[0076] The composition of the electroplating sludge in Example 6 is the same as that in Example 5, according to... Figure 1 The method shown is used to process:

[0077] Step 1: Pulping treatment: Electroplating sludge and water are mixed in a mass ratio of 1:1 and fed into a pulping machine for stirring at a stirring speed of 300 r / min.

[0078] Step 2: Co-processing: The electroplating sludge after pulping is fed into the biological oxidation liquid at a volume ratio of 1:3 and mixed for 18 hours.

[0079] Step 3 Filtration: Solid-liquid separation is performed on the co-processed product to obtain filtrate and filter residue. The filtrate is fed into the next step of ion exchange, and the filter residue is fed into the subsequent gold extraction operation.

[0080] Step 4: Ion exchange process: The filtrate flows through the exchange column for ion exchange. During the process, the filtrate is always higher than the cation exchange column until the effluent reaches the flow point.

[0081] Step 5: Desorption: The ion exchange column was treated with 20% hydrochloric acid to obtain a zinc-enriched solution. The zinc content was found to be 46%.

Claims

1. A method for synergistic biological oxidation pretreatment of resource-based electroplating sludge, characterized in that, It includes the following steps: Step 1, pulping treatment: Electroplating sludge and water are fed into a pulping machine for pulping treatment; Step 2, Co-processing: The electroplating sludge after pulping is fed into a biological oxidation solution, which is a leachate produced during the biological oxidation of acidic refractory gold ore. The mixture reacts to obtain the co-processed product. Step 3, Filtration: The co-processed product obtained in Step 2 is subjected to solid-liquid separation to obtain filtrate and filter residue respectively; the filtrate contains valuable metal elements from electroplating sludge, and the filter residue contains refractory gold ore treated by bacteria in biological oxidation liquid and suspended solids that are insoluble in acid; Step 4, Ion exchange process: The filtrate obtained in step 3 is fed into the cation exchange resin from top to bottom, and the valuable metal ions in the filtrate will be adsorbed into the cation exchange resin. Step 5, Desorption: Treat the cation exchange resin with an acid solution to obtain a enriched solution containing copper and zinc ions.

2. The method for synergistic biological oxidation pretreatment of resource-based electroplating sludge according to claim 1, characterized in that, In step one, the ratio of electroplating sludge to water is (1~1.8):1 by mass, and the stirring speed during slurry treatment is 300~500 r / min.

3. The method for synergistic biological oxidation pretreatment of resource-based electroplating sludge according to claim 1, characterized in that, In step two, the valuable element is selected from one or more of copper and zinc.

4. The method for synergistic biological oxidation pretreatment of resource-based electroplating sludge according to claim 1, characterized in that, In step two, the ratio of electroplating sludge after pulping treatment to biological oxidation liquid is 1:(2~3) by volume; the co-treatment temperature is 25~30℃, and the co-treatment time is 15~20h.

5. The method for synergistic biological oxidation pretreatment of resource-based electroplating sludge according to claim 1, characterized in that, In step four, during the ion exchange process, the filtrate height is always higher than the cation exchange resin layer. When the effluent concentration of the cation exchange resin reaches the flow point, the filtrate feeding is stopped, and the ion exchange ends.

6. The method for synergistic biological oxidation pretreatment of resource-based electroplating sludge according to claim 1, characterized in that, In step five, the acid solution is selected from inorganic acids, specifically including hydrochloric acid, sulfuric acid, and nitric acid, with a concentration of 5% to 20% by mass.

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