A method for recovering and producing high-quality cobalt hydroxide from copper-cobalt raffinate

Abstract

This invention discloses a method for recovering and producing high-quality cobalt hydroxide from copper-cobalt raffinate, comprising: dividing the copper-cobalt raffinate into two parts; mixing the first part of the copper-cobalt raffinate with low-grade copper-cobalt oxide ore for a first-stage neutralization reaction, with the final pH at 1.2–2.2; mixing the first-stage overflow with an alkaline agent for a second-stage neutralization reaction, with the final pH at 3.5–4.2; mixing the second-stage overflow, the first filter press liquid, and the alkaline agent for a third-stage neutralization reaction, with the final pH at 6.2–7.8; mixing the third-stage underflow with the second part of the copper-cobalt raffinate and sulfuric acid for redissolution, controlling the final pH at 3.5–4.2; then filtering to obtain a redissolution residue and a second filter press liquid; the second filter press liquid is then extracted, iron removed, and cobalt precipitated to obtain a cobalt-precipitated liquid and cobalt hydroxide product. This method can save alkaline reagents, and helps to release the system's cobalt hydroxide production capacity. The cobalt hydroxide product has low impurity content, high cobalt grade, and good quality.

Description

Technical Field

[0001] This invention relates to the field of copper-cobalt hydrometallurgical technology, and in particular, to a method for recovering and producing high-quality cobalt hydroxide from copper-cobalt raffinate. Background Technology

[0002] Cobalt, as a rare metal, plays a crucial role in the new energy industry. However, cobalt resources are extremely unevenly distributed globally. The Democratic Republic of Congo (DRC) holds 49.45% of the world's cobalt reserves, and a staggering 63% of cobalt production originates from this region. DRC cobalt resources are primarily copper-cobalt associated ores, and the processing method is mostly hydrometallurgical. This involves a series of processes: sulfuric acid leaching, extraction, and electrowinning to recover cathode copper. The raffinate is then purified and subjected to a single / multi-stage cobalt precipitation to produce cobalt hydroxide.

[0003] In recent years, with the increased mining of cobalt resources, a large amount of low-grade copper-cobalt oxide ore needs to enter the production process, posing certain challenges to the recovery of copper and cobalt resources in the smelting system. On the one hand, the low cobalt concentration and high impurity content in the ore leachate result in a large throughput of the cobalt precipitation system, shortening the reaction time and ultimately leading to low-quality cobalt hydroxide products. This negatively impacts the transportation costs of subsequent cobalt hydroxide products and cobalt refining. On the other hand, the raffinate is directly fed into the cobalt precipitation process, where the sulfuric acid is not effectively utilized, and the consumption of neutralizing agents such as lime increases, raising production costs.

[0004] Chinese patent CN107460315A discloses a method for concentrating, separating, neutralizing, and precipitating copper and cobalt in raffinate using nanofiltration membranes, and Chinese patent CN109266837A discloses a method for recovering copper and cobalt from cobalt-containing waste liquid in wet copper smelting. Both of these technologies mention the use of nanofiltration membranes for concentration and separation, which achieves the concentration and enrichment of metal ions and the separation and recovery of sulfuric acid. However, the nanofiltration membrane described above has high requirements for the treatment solution. It must be pretreated to remove impurities such as solid particles, suspended solids, and oils. Secondly, most metal ions in the concentrated liquid are enriched, and the concentration is increased, which has a certain impact on the production load of the subsequent impurity removal process and the quality of cobalt hydroxide products. Finally, after the sulfuric acid is separated, the acid concentration in the cobalt-containing concentrate can still reach 18 g / L. Directly entering the neutralization process will cause the loss of sulfuric acid and neutralizing agent, increasing production costs. Another Chinese patent, CN115141939A, discloses a method for neutralizing raffinate and comprehensively recovering copper and cobalt using flotation tailings. In this method, flotation tailings are used instead of lime slurry to neutralize the raffinate to pH 3.5-4, which successfully reduces lime consumption and increases the recovery and utilization of copper and cobalt in the flotation tailings. Subsequently, copper is precipitated by lime slurry (pH 5.5-6) ​​and cobalt is precipitated by magnesium oxide to produce cobalt hydroxide products. However, for some large-scale production systems, the above technology still has the following shortcomings: First, by using flotation tailings to directly neutralize the raffinate to pH 3.5-4 and then carry out thickening and sedimentation separation, the flotation tailings leaching residue and the iron-aluminum neutralization residue generated by neutralization are all settled at one time, resulting in a large amount of residue, increased equipment operating pressure, high risk of mixing, and limited processing capacity of the entire neutralization process; Second, all impurity elements in the raffinate enter the neutralization system, making one-time impurity removal technically difficult, which has an adverse effect on the impurity content of cobalt hydroxide products, making it difficult to produce high-quality cobalt hydroxide products. Summary of the Invention

[0005] This invention provides a method for recovering and producing high-quality cobalt hydroxide from copper-cobalt raffinate, thereby solving the technical problems of existing technologies that consume large amounts of neutralizing agents and cannot simultaneously obtain high-quality cobalt hydroxide products.

[0006] This invention provides a method for recovering and producing high-quality cobalt hydroxide from copper-cobalt raffinate, comprising the following steps:

[0007] The copper-cobalt raffinate is divided into two parts. The first part of the copper-cobalt raffinate is mixed and reacted with low-grade copper-cobalt oxide ore. The final pH value of the reaction is 1.2 to 2.2. After the reaction is completed, the raffinate is separated into a bottom stream and an overflow stream. The bottom stream enters the leaching process, and the overflow stream enters the next step.

[0008] The overflow is mixed with an alkaline agent and reacted. The final pH value of the reaction is 3.5-4.2. After the reaction is completed, the mixture is separated into two underflows and two overflows. The two underflows enter the filter press process to obtain filter residue and the first filter liquid. The two overflows proceed to the next step.

[0009] The resulting two-stage overflow and first-stage filtrate are mixed with an alkaline agent and reacted. The final pH value of the reaction is 6.2-7.8. After the reaction is completed, the mixture is separated into three-stage underflow and three-stage overflow. The three-stage overflow is reused as a neutral water supply system. The three-stage underflow proceeds to the next step.

[0010] The three-stage underflow and the second part of the copper-cobalt raffinate, as well as sulfuric acid, are redissolved. The pH value at the reaction endpoint is controlled to be 3.5-4.2. The solution is then filtered to obtain a redissolved residue and a second filtrate. The redissolved residue is washed and discharged. The second filtrate is extracted, iron is removed, and cobalt is precipitated to obtain a cobalt-precipitated liquid and a cobalt hydroxide product.

[0011] Furthermore, the copper-cobalt raffinate includes the raffinate formed after copper is initially extracted from copper-cobalt oxide ore during the hydrometallurgical process.

[0012] Furthermore, the copper-cobalt raffinate includes a high-copper-cobalt raffinate formed by extracting copper from the feed liquid after sulfuric acid leaching of ore in a copper-cobalt hydrometallurgical system, and a low-copper-cobalt raffinate formed by extracting copper from the washing liquid after washing of ore leaching residue in a copper-cobalt hydrometallurgical system.

[0013] Furthermore, the first portion of the copper-cobalt raffinate is mainly composed of low-copper-cobalt raffinate.

[0014] Furthermore, the second part of the copper-cobalt raffinate is mainly composed of high-copper-cobalt raffinate.

[0015] Furthermore, the low-grade copper-cobalt oxide ore includes flotation tailings, raw copper-cobalt oxide ore, or mineralized waste rock.

[0016] Furthermore, the alkaline agent includes lime, limestone, sodium carbonate, or magnesium oxide.

[0017] Furthermore, the resulting two-stage overflow and the resulting filtrate are mixed with an alkaline agent and reacted. The final pH value of the reaction is 6.8 to 7.2. Preferably, the final pH value is controlled within the range of 6.8 to 7.2.

[0018] Further, the second filtrate is subjected to extraction, iron removal and cobalt precipitation, which includes: extracting copper from the second filtrate to obtain raffinate, adding lime milk and oxidant to the raffinate to remove iron, obtaining iron-removed liquid, adding active magnesium oxide to the iron-removed liquid to precipitate cobalt, obtaining cobalt-precipitated liquid and cobalt hydroxide product.

[0019] Furthermore, the cobalt precipitation process consists of two stages. The first stage produces cobalt hydroxide, and then lime slurry is added to the liquid after the first stage cobalt precipitation for a second stage cobalt precipitation, resulting in a second stage cobalt precipitation slag and a second stage cobalt precipitation liquid. The second stage cobalt precipitation slag is returned to the iron removal process, and the second stage cobalt precipitation liquid is reused by the system.

[0020] The present invention has the following beneficial effects:

[0021] In the treatment of the first part of the copper-cobalt raffinate in the invention, a three-stage neutralization method is first adopted to remove most of the impurity elements in the solution in the first and second stages of neutralization, thereby reducing the impurity content entering the cobalt precipitation system from the source. At the same time, by using low-grade copper-cobalt oxide ore as the alkaline agent in the first stage of neutralization, the final pH of 1.2 to 2.2 ensures a good copper-cobalt leaching effect. This not only solves the problem of copper-cobalt recovery from low-grade copper-cobalt oxide ore and the problem of high sulfuric acid concentration in the first part of the copper-cobalt raffinate, but also saves the cost of alkaline agents such as lime.

[0022] Secondly, by re-dissolving, the copper-cobalt slag from the three-stage neutralization is reacted with the second part of the copper-cobalt raffinate, which not only increases the copper-cobalt concentration in the second part of the copper-cobalt raffinate but also consumes the sulfuric acid in the second part of the copper-cobalt raffinate, thus saving the cost of reagents such as lime. At the same time, the pH range of the second part of the copper-cobalt raffinate is optimized to 3.5-4.2 by using the three-stage neutralization slag. Some of the iron-aluminum slag precipitates during the re-dissolving process and is discharged from the system with the slag.

[0023] Finally, the method provided by this invention can obtain raffinate with lower impurities and acid concentrations and higher cobalt enrichment concentrations. While maintaining the cobalt precipitation system in a low-load production mode, it can still achieve the goal of high cobalt hydroxide production. Moreover, the produced cobalt hydroxide has lower impurity content, higher cobalt grade, and better quality, which is beneficial for reducing product transportation costs and cobalt refining process products.

[0024] In addition to the objectives, features, and advantages described above, the present invention has other objectives, features, and advantages. The invention will now be described in further detail with reference to the figures. Attached Figure Description

[0025] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0026] Figure 1 This is a schematic diagram of the process flow of a preferred embodiment of the present invention. Detailed Implementation

[0027] To make the inventive objectives, technical solutions, and beneficial effects of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the embodiments described in this specification are merely illustrative of the invention and are not intended to limit the invention.

[0028] For simplicity, this paper only explicitly discloses some numerical ranges. However, any lower limit can be combined with any upper limit to form an undefined range; and any lower limit can be combined with other lower limits to form an undefined range, just as any upper limit can be combined with any other upper limit to form an undefined range. Furthermore, although not explicitly stated, every point or individual value between the endpoints of a range is included within that range. Therefore, each point or individual value can serve as its own lower or upper limit and be combined with any other point or individual value, or with other lower or upper limits, to form an undefined range.

[0029] In this description, it should be noted that, unless otherwise stated, "above" and "below" include the stated number, "multiple" in "one or more" means two or more, and "more than" in "one or more" means two or more.

[0030] This invention provides a method for recovering and producing high-quality cobalt hydroxide from copper-cobalt raffinate, comprising the following steps:

[0031] The copper-cobalt raffinate is divided into two parts. The first part of the copper-cobalt raffinate is mixed and reacted with low-grade copper-cobalt oxide ore. The final pH value of the reaction is 1.2 to 2.2. After the reaction is completed, the raffinate is separated into a bottom stream and an overflow stream. The bottom stream enters the leaching process, and the overflow stream enters the next step.

[0032] The overflow is mixed with an alkaline agent and reacted. The final pH value of the reaction is 3.5-4.2. After the reaction is completed, the mixture is separated into two underflows and two overflows. The two underflows enter the filter press process to obtain filter residue and the first filter liquid. The two overflows proceed to the next step.

[0033] The resulting two-stage overflow and first-stage filtrate are mixed with an alkaline agent and reacted. The final pH value of the reaction is 6.2-7.8. After the reaction is completed, the mixture is separated into three-stage underflow and three-stage overflow. The three-stage overflow is reused as a neutral water supply system. The three-stage underflow proceeds to the next step.

[0034] The three-stage underflow and the second part of the copper-cobalt raffinate, as well as sulfuric acid, are redissolved. The pH value at the reaction endpoint is controlled to be 3.5-4.2. The solution is then filtered to obtain a redissolved residue and a second filtrate. The redissolved residue is washed and discharged. The second filtrate is extracted, iron is removed, and cobalt is precipitated to obtain a cobalt-precipitated liquid and a cobalt hydroxide product.

[0035] In the embodiments, solid-liquid separation can be performed using a thickener, filter press, etc.

[0036] like Figure 1 As shown, the embodiments of this application use a three-stage neutralization method to enrich some copper and cobalt elements in the first part of the copper-cobalt raffinate and the low-grade copper-cobalt oxide ore into the three-stage neutralization slag phase. At the same time, most of the impurities in the first part of the copper-cobalt raffinate are removed in the first-stage and second-stage neutralization processes. The specific process is as follows:

[0037] (1) The first part of copper-cobalt raffinate and low-grade copper-cobalt oxide ore are neutralized in one stage: The first part of copper-cobalt raffinate and low-grade copper-cobalt oxide ore are pumped into the first stage neutralization stirring tank for stirring and reaction. The pH range at the end of the reaction is controlled at 1.2 to 2.2 (in this embodiment, the amount of low-grade copper-cobalt oxide ore added is adjusted in a timely manner by monitoring the pH change trend). The amount of low-grade copper-cobalt oxide ore added is adjusted according to the pH value at the end of the first stage neutralization. The bottom flow of the first stage neutralization thickener after the reaction is pumped to the ore leaching process to continue to recover valuable metal elements such as copper and cobalt in the ore.

[0038] In some embodiments, the pH control range at the end of a neutralization process is selected as 2.0 to 2.2. Based on the premise that the thickener can settle and separate normally, the pH value is controlled as high as possible to reduce the acid concentration in the liquid after neutralization and save lime consumption in subsequent production processes.

[0039] (2) The first-stage neutralized liquid is neutralized with an alkaline agent in the second stage: The overflow liquid from the first-stage neutralization thickener and the alkaline agent are pumped together into the second-stage neutralization stirring reaction tank. The pH range of the reaction endpoint is controlled to be 3.5 to 4.2 (the amount of alkaline agent, taking lime milk as an example, varies depending on the content of impurities such as iron and aluminum in the raffinate, the effective components of lime, and the concentration of lime milk. In this embodiment, the pH of the endpoint reaction is controlled to be 3.5 to 4.2 by adding lime milk, and the amount of lime milk added is adjusted in time according to the pH change). The amount of alkaline agent lime milk is adjusted according to the pH value of the second-stage neutralization endpoint. The bottom flow of the second-stage neutralization thickener after the reaction is pumped to the filter press workshop. After filter press, the filter residue is discharged and the filtrate is recycled. The filter press liquid enters the third-stage neutralization process together with the overflow liquid from the second-stage neutralization thickener.

[0040] (3) The liquid after the second-stage neutralization is neutralized in a third stage with an alkaline agent: The overflow from the second-stage neutralization thickener and the alkaline agent (such as lime slurry) are pumped together into the third-stage neutralization stirred reaction tank. The pH range of the final reaction is controlled to be 6.2-7.8. (The amount of alkaline agent used is lime slurry, which varies depending on the content of impurities such as iron and aluminum in the raffinate, the effective components of lime, and the concentration of lime slurry. In this embodiment, lime slurry is added to control the pH of the final reaction to 6.2-7.8, so that the raffinate is completely precipitated.) The copper and cobalt elements are enriched in the three-stage neutralization slag phase. In actual production, the amount of lime slurry added needs to be adjusted in a timely manner according to the pH change. The valuable metal elements such as copper and cobalt in the first part of the copper and cobalt raffinate are enriched in the three-stage neutralization slag phase. The amount of alkaline agent is adjusted according to the pH value at the end of the three-stage neutralization (if the pH is high, the flow rate of alkaline agent entering the three-stage neutralization is reduced, and vice versa). The bottom flow of the three-stage neutralization thickener after the reaction is sent to the redissolution process, and the overflow liquid enters the return water tank for system reuse.

[0041] In some embodiments, the final pH range of the three-stage neutralization process is controlled to be 6.8 to 7.2, which ensures the complete precipitation of valuable metals such as copper and cobalt while avoiding unnecessary waste of lime.

[0042] The embodiments of this application use a redissolution method to dissolve and enrich copper and cobalt elements in the three-stage neutralization slag into the redissolution liquid. Then, through an extraction copper-iron removal-two-stage cobalt precipitation process, high-quality cobalt hydroxide product is produced. The specific process is as follows:

[0043] (1) Redissolving the three-stage neutralization residue with the second part of copper-cobalt raffinate: The bottom flow of the three-stage neutralization thickener is filtered by pressure. The filter residue is slurried with the second part of copper-cobalt raffinate, and acid is added to carry out a redissolution reaction to enrich copper and cobalt into the solution. The pH range of the reaction endpoint is controlled at 3.5 to 4.2. The amount of copper-cobalt raffinate and sulfuric acid is adjusted according to the pH value of the redissolution reaction endpoint. The redissolution residue after the reaction is returned to the leaching, washed and discharged. The concentrated redissolution liquid is used to produce cobalt hydroxide products.

[0044] The core control point of this application embodiment is to control the pH value of the redissolution reaction process. The copper-cobalt raffinate contains a high acid content. When the pH of the reaction process is high, the pH can be reduced by increasing the flow rate of the copper-cobalt raffinate or by directly adding concentrated sulfuric acid. The specific method can be flexibly adjusted according to the actual production conditions.

[0045] (2) Redissolved liquid extraction-iron removal-two-stage cobalt precipitation: The redissolved liquid is pumped into the extraction to extract copper. The obtained raffinate is then mixed with lime milk and oxidant to remove iron. The iron-removed liquid is then mixed with active magnesium oxide to precipitate cobalt, resulting in a high-quality cobalt hydroxide product and a first-stage cobalt precipitation liquid. The cobalt precipitation liquid is then mixed with lime milk for a second-stage cobalt precipitation. The second-stage cobalt precipitation slag is returned to the iron removal process, and the second-stage cobalt precipitation liquid is used for system reuse.

[0046] In some embodiments, the number of two-stage neutralization stirring reaction tanks is not less than 2, the reaction time is not less than 4 hours, and the reaction temperature is room temperature to 90°C.

[0047] In some embodiments, the number of the three-stage neutralization stirring reaction tanks is not less than two, the reaction time is not less than 4 hours, and the reaction temperature is from room temperature to 90°C.

[0048] In some embodiments, there are no fewer than two remelting reaction stirring tanks, the reaction time is no less than 2 hours, and the reaction temperature is between room temperature and 90°C.

[0049] Having at least two reaction tanks helps to better control the pH range at the reaction endpoint and the uniformity of the reaction. In actual production, adding alkaline reagents only in a single tank often leads to unstable pH control and uneven reaction. It is necessary to add subsequent reaction tanks to fine-tune the pH and stir the mixture, extend the reaction time, and make the reaction more thorough.

[0050] The above reaction temperature ranges from room temperature to 90°C. Under room temperature conditions, this patented solution can produce high-quality cobalt hydroxide. Heating can further accelerate the reaction rate, which is beneficial for the complete reaction of the alkaline agent. At the same time, the slag produced by the neutralization reaction has better settling performance, faster solid-liquid separation rate, and more stable production system.

[0051] In the embodiments of this application, the low-grade oxide ore includes, but is not limited to, flotation tailings, copper-cobalt oxide ore, and mineralization waste rock, which contain small amounts of valuable metal elements such as copper and cobalt, are mainly oxide ores, and can react with sulfuric acid. The main purpose of the low-grade oxide ore is to replace lime in consuming the sulfuric acid component in the leaching solution, reduce the consumption of alkaline agents in the neutralization process, and at the same time, after the acid-consuming substances in the ore are consumed, they enter the leaching process to allow copper and cobalt to continue to leach, thus saving the sulfuric acid consumed in the leaching process.

[0052] In the embodiments of this application, the source of the copper-cobalt raffinate is the raffinate formed after the copper is initially extracted during the hydrometallurgical process of copper-cobalt oxide ore. The solution contains cobalt and some copper that has not been fully extracted. In this technical field, without considering economic factors, the raffinate in all copper-cobalt ore hydrometallurgical processes can in principle adopt this method and should all fall within the protection scope of this method.

[0053] In copper-cobalt hydrometallurgical systems, there are two sources of raffinate containing copper and cobalt. The first is the copper-cobalt raffinate formed after copper extraction from the ore following sulfuric acid leaching; this raffinate is characterized by high concentrations of copper, cobalt, and acid, and is called high-copper-cobalt raffinate. The second is the copper-cobalt raffinate formed after copper extraction from the washing liquid following washing (pressure filtration or CCD countercurrent washing) of the ore leaching residue; this raffinate has lower concentrations of copper, cobalt, and acid than the former, and is called low-copper-cobalt raffinate. The concentration of copper, cobalt, and acid in the raffinate varies depending on the characteristics of the production system and the type of ore processed.

[0054] In some embodiments, the first portion of copper-cobalt raffinate is selected to have low copper-cobalt raffinate as the main component.

[0055] In some embodiments, the second portion of copper-cobalt raffinate is selected to be composed mainly of high copper-cobalt raffinate.

[0056] In the process described in this method, the low-copper-cobalt raffinate is preferred for the three-stage neutralization process, mainly because its copper, cobalt, and acid concentrations are relatively low, allowing it to directly enter the neutralization process and reducing the consumption of alkaline reagents. Similarly, the high-copper-cobalt raffinate is preferred for the redissolution process, mainly because this process requires the copper and cobalt to be enriched back into the liquid phase. The high-copper-cobalt raffinate contains a high amount of copper and cobalt, so less copper and cobalt needs to be dissolved. At the same time, the high-copper-cobalt raffinate has a high acid concentration, so less new acid needs to be added, thus saving production costs.

[0057] It should be noted that this scheme is a preferred option. Without considering economic factors, both high-copper-cobalt raffinate and low-copper-cobalt raffinate can enter the three-stage neutralization or redissolution process, which is technically feasible.

[0058] In the embodiments of this application, the low-grade copper-cobalt oxide ore includes flotation tailings, copper-cobalt oxide ore, or mineralization waste rock. Technically, the ore used in this process only needs to be able to react with sulfuric acid; its main function is to replace alkaline agents such as lime, saving production costs. Furthermore, the small amount of copper and cobalt contained in the ore can be effectively recovered, improving the system's copper and cobalt recovery rate.

[0059] In the embodiments of this application, the alkaline agent (including the alkaline agent used in the first-stage overflow and the second-stage overflow) includes, but is not limited to, alkaline agents that can neutralize acids, such as lime, limestone, sodium carbonate, and magnesium oxide, and may also include hydroxides, carbonates, alkali metal oxides, etc.

[0060] Example

[0061] The following embodiments describe the disclosure of this application in more detail. These embodiments are merely illustrative, as various modifications and variations will be apparent to those skilled in the art within the scope of the disclosure of this application. Unless otherwise stated, all parts, percentages, and ratios reported in the following embodiments are based on weight, and all reagents used in the embodiments are commercially available or synthesized by conventional methods and can be used directly without further processing, and the instruments used in the embodiments are commercially available.

[0062] Example 1

[0063] This embodiment uses low-copper-copper raffinate, high-copper-copper raffinate, and low-grade copper-copper oxide ore from the raw ore production process of a copper-copper hydrometallurgical enterprise in the Democratic Republic of Congo. The main elemental analysis results are shown in Tables 1 and 2.

[0064] Table 1. Detection results of major elements (g / L) in the copper-cobalt raffinate from a copper-cobalt hydrometallurgical plant in the Democratic Republic of Congo.

[0065]

[0066] Table 2. Elemental analysis results of low-grade copper-cobalt oxide ore from a copper-cobalt hydrometallurgical plant in the Democratic Republic of Congo.

[0067]

[0068] This embodiment uses a method for recovering and producing high-quality cobalt hydroxide from copper-cobalt raffinate, and the specific process is as follows:

[0069] (1) First-stage neutralization: The first portion of copper-cobalt raffinate and low-grade copper-cobalt oxide ore are pumped into a first-stage neutralization mixing tank for stirring and reaction. There are three first-stage neutralization mixing tanks. The ore is fed into the next mixing tank sequentially via overflow, and finally enters a thickener to achieve liquid-solid separation. The amount of the first portion of copper-cobalt raffinate used in the first-stage neutralization is 400 m³. 3 / h, including 300m 3 / h low copper-cobalt raffinate and 100m 3 / h high copper-cobalt raffinate, reaction temperature is room temperature, reaction time is 2h, control the pH range of the reaction endpoint is 1.2 to 1.5, low-grade copper-cobalt ore consumption is 40 to 60t / h, and the bottom flow of the first-stage neutralization thickener is pumped to the ore leaching process.

[0070] (2) Two-stage neutralization: The overflow from the first-stage neutralization thickener is pumped into the second-stage neutralization mixing tank, and an appropriate amount of lime slurry is added simultaneously. The pH range at the reaction endpoint is controlled to be 3.5-3.8. There are two second-stage neutralization mixing tanks. The mixture flows into the next mixing tank sequentially via overflow, and finally enters the thickener for clarification and separation. The reaction temperature of the second-stage neutralization is 40-50℃, and the reaction time is 4 hours. After the reaction, the underflow from the second-stage neutralization thickener is pumped to the filter press workshop. After filter pressing, the filter residue is discharged, and the filtrate enters the next process along with the overflow from the second-stage neutralization thickener.

[0071] (3) Three-stage neutralization: The overflow from the two-stage neutralization thickener is pumped into the three-stage neutralization mixing tank, and an appropriate amount of lime slurry is added simultaneously. The pH range at the reaction endpoint is controlled to be 6.2-7.8. There are two three-stage neutralization mixing tanks. The liquid is fed into the next mixing tank in sequence by overflow, and finally enters the thickener for clarification and separation. The reaction temperature of the three-stage neutralization is 30-45℃, and the reaction time is 4 hours. After the reaction, the underflow from the three-stage neutralization thickener is pumped to the redissolution process, and the overflow liquid enters the smelting system return water tank for reuse as neutral water in the system.

[0072] (4) Redissolution: The underflow from the three-stage neutralization thickener is filtered by pressure. The filter residue is mixed with the copper-cobalt raffinate from the second stage, and a small amount of sulfuric acid is added simultaneously to carry out the redissolution reaction, controlling the final pH range to 3.5–4.2. Two redissolution stirring tanks are used, with the residue flowing sequentially into the next stirring tank via overflow, and finally into the pressure filter to achieve solid-liquid separation. The amount of copper-cobalt raffinate used in the second stage of the redissolution process is 160 m³. 3 / h, using high copper and cobalt raffinate, reaction temperature is 70-90℃, reaction time is 4h, after reaction the slag phase is returned to leaching, washed and discharged, the liquid phase is used to produce cobalt hydroxide products.

[0073] (5) Redissolution after extraction-iron removal-cobalt precipitation: The redissolution after extraction is pumped into the extraction workshop to extract copper, reducing the copper concentration to less than 0.1 g / L. The resulting raffinate is then treated with lime milk to remove iron. The iron removal reaction temperature is 70-80℃, the reaction time is 6 h, and the final pH is 4.0-4.7. The iron removal after extraction is then treated with active magnesium oxide to precipitate cobalt. The cobalt precipitation reaction temperature is 50-60℃, the reaction time is 6 h, and the final pH is 6.0-7.2. High-quality cobalt hydroxide product and cobalt precipitation after extraction are obtained. The cobalt precipitation after extraction is then treated with lime milk for a second stage of cobalt precipitation. The second stage of cobalt precipitation is carried out at room temperature for 4 h, and the final pH is ~8.2. The cobalt precipitation slag from the second stage is returned to the iron removal process, and the cobalt precipitation after extraction is reused as neutral water.

[0074] It should be noted that flocculant addition is a mature technology in this industry. The design of thickener equipment already includes the method and location for flocculant addition. Its main function is to aggregate small particles and improve the settling rate. In this invention, flocculant addition only needs to ensure normal settling and separation inside the thickener and prevent mixing. There are no special requirements. This technology is well known in the industry.

[0075] In this implementation case, the main elemental analysis results for the first-stage neutralization slag, the second-stage neutralization slag, the third-stage neutralization slag, the pre-iron removal liquid, and the high-quality cobalt hydroxide product are shown in Tables 3 to 5.

[0076] Table 3. Detection results of major elements in the solid residue samples produced by the three-stage neutralization process.

[0077] element(%) Cu Co Fe Mn Ca Mg Al <![CDATA[SiO2]]> A neutralizing scum 0.23 0.14 1.76 0.07 0.49 2.48 4.53 61.54 Second stage neutralization residue 0.29 0.10 4.00 0.33 23.12 0.75 0.95 4.80 Three stages of neutralizing residue 6.01 3.37 1.99 1.06 19.02 3.27 2.45 2.44

[0078] Table 4. Detection results of major elements in the solution entering the cobalt precipitation system (pre-iron removal solution).

[0079] element Cu Co Fe Mn Al Content (g / L) 0.07 7.60 0.47 2.60 0.60

[0080] In this embodiment, the cobalt concentration in the solution entering the cobalt precipitation system was enriched from 2.72 g / L in the original copper-cobalt raffinate to 7.60 g / L, with an enrichment factor of 2.79. At the same time, impurity elements such as Cu, Fe, and Al were reduced to varying degrees, with reductions of 96.55%, 81.99%, and 58.90%, respectively. This created favorable conditions for the production of high-quality cobalt hydroxide products, and the produced cobalt hydroxide products were of grade one.

[0081] Example 2

[0082] This embodiment uses low-copper-copper raffinate, high-copper-copper raffinate, and low-grade copper-copper oxide ore from the raw ore production process of a copper-copper hydrometallurgical enterprise in the Democratic Republic of Congo. The main elemental analysis results are shown in Tables 5 and 6.

[0083] Table 5. Detection results of major elements (g / L) in the copper-cobalt raffinate from a copper-cobalt hydrometallurgical plant in the Democratic Republic of Congo.

[0084]

[0085] Table 6. Elemental Analysis Results of Low-Grade Copper-Cobalt Ore from a Copper-Cobalt Hydrometallurgical Enterprise in the Democratic Republic of Congo

[0086]

[0087] This embodiment uses a method for recovering and producing high-quality cobalt hydroxide from copper-cobalt raffinate, and the specific process is as follows:

[0088] (1) First-stage neutralization: The first portion of copper-cobalt raffinate and low-grade copper-cobalt oxide ore are pumped into a first-stage neutralization mixing tank for stirring and reaction. There are three first-stage neutralization mixing tanks. The ore is poured into the next mixing tank sequentially via overflow, and finally enters a thickener to achieve liquid-solid separation. The amount of copper-cobalt raffinate used in the first-stage neutralization is 200 m³. 3 / h, including 100m 3 / h low copper-cobalt raffinate and 100m3 / h high copper-cobalt raffinate, reaction temperature is 70~90℃, reaction time is 4.5h, control the pH range of the reaction endpoint is 1.8~2.2, consumption of low-grade copper-cobalt oxide ore is 20~25t / h, and the bottom flow of the first-stage neutralization thickener is pumped to the ore leaching process.

[0089] (2) Two-stage neutralization: The overflow from the first-stage neutralization thickener is pumped into the second-stage neutralization mixing tank, and an appropriate amount of lime slurry is added simultaneously. The pH range at the reaction endpoint is controlled to be 3.8-4.2. There are two second-stage neutralization mixing tanks. The mixture flows into the next mixing tank sequentially via overflow, and finally enters the thickener for clarification and separation. The reaction temperature of the second-stage neutralization is 70-90℃, and the reaction time is 9 hours. After the reaction, the underflow from the second-stage neutralization thickener is pumped to the filter press workshop. After filter pressing, the filter residue is discharged, and the filtrate enters the next process along with the overflow from the second-stage neutralization thickener.

[0090] (3) Three-stage neutralization: The overflow from the two-stage neutralization thickener is pumped into the three-stage neutralization mixing tank, and an appropriate amount of lime slurry is added simultaneously. The pH range at the reaction endpoint is controlled to be 6.2-7.8. There are two three-stage neutralization mixing tanks. The liquid is fed into the next mixing tank in sequence by overflow, and finally enters the thickener for clarification and separation. The reaction temperature of the three-stage neutralization is 70-90℃, and the reaction time is 9 hours. After the reaction, the underflow from the three-stage neutralization thickener is pumped to the redissolution process, and the overflow liquid enters the smelting system return water tank for reuse as neutral water in the system.

[0091] (4) Redissolution: The underflow from the three-stage neutralization thickener is filtered by pressure. The filter residue is mixed with the copper-cobalt raffinate from the second stage, and a small amount of sulfuric acid is added simultaneously to carry out the redissolution reaction, controlling the final pH range to 3.5–4.2. Two redissolution stirring tanks are used, with the residue flowing sequentially into the next stirring tank via overflow, and finally into the pressure filter to achieve solid-liquid separation. The amount of copper-cobalt raffinate used in the second stage of the redissolution process is 150 m³. 3 / h, using high copper and cobalt raffinate, reaction temperature 40~70℃, reaction time 4h, after reaction the slag phase is returned to leaching, washed and discharged, the liquid phase is used to produce cobalt hydroxide products;

[0092] (5) Redissolution after extraction-iron removal-cobalt precipitation: The redissolution after extraction is pumped into the extraction workshop to extract copper, reducing the copper concentration to less than 0.1 g / L. The resulting raffinate is then treated with lime milk to remove iron. The iron removal reaction temperature is 70-80℃, the reaction time is 6 h, and the final pH is 4.0-4.7. The iron removal after extraction is then treated with active magnesium oxide to precipitate cobalt. The cobalt precipitation reaction temperature is 50-60℃, the reaction time is 6 h, and the final pH is 6.0-7.2. High-quality cobalt hydroxide product and cobalt precipitation after extraction are obtained. The cobalt precipitation after extraction is then treated with lime milk for a second stage of cobalt precipitation. The second stage of cobalt precipitation is carried out at room temperature for 4 h, and the final pH is ~8.2. The cobalt precipitation slag from the second stage is returned to the iron removal process, and the cobalt precipitation after extraction is reused as neutral water.

[0093] In this implementation case, the main elemental analysis results for the first-stage neutralization slag, the second-stage neutralization slag, the third-stage neutralization slag, the pre-iron removal liquid, and the high-quality cobalt hydroxide product are shown in Tables 7 to 9.

[0094] Table 7. Detection results of major elements in the solid residue samples produced by the three-stage neutralization process.

[0095]

[0096]

[0097] Table 8. Detection results of major elements in the solution entering the cobalt precipitation system (pre-iron removal solution).

[0098] element Cu Co Fe Mn Al Content (g / L) 0.07 5.54 0.20 2.25 0.62

[0099] Table 9. Detection results of major elements in high-quality cobalt hydroxide products produced by the cobalt precipitation system.

[0100] element Cu Co Fe Mn Ca Mg Al content(%) 0.57 40.69 0.04 3.76 0.30 2.75 0.77

[0101] In this embodiment, the cobalt concentration in the solution entering the cobalt precipitation system was enriched from 2.42 g / L in the original copper-cobalt raffinate to 5.54 g / L, with an enrichment factor of 2.29. At the same time, impurity elements such as Cu, Fe, and Al were reduced to varying degrees, with reductions of 97.11%, 92.19%, and 56.03%, respectively. This created favorable conditions for the production of high-quality cobalt hydroxide products, and the produced cobalt hydroxide products were of grade one.

[0102] The present invention discloses a method for producing high-quality cobalt hydroxide from copper-cobalt raffinate. The process includes the following steps: (1) neutralizing a first-stage copper-cobalt raffinate with low-grade copper-cobalt oxide ore; (2) neutralizing the first-stage neutralized liquid with an alkaline agent in a second-stage neutralization; (3) neutralizing the second-stage neutralized liquid with an alkaline agent in a third-stage neutralization; (4) redissolving the third-stage neutralization residue with a second-stage copper-cobalt raffinate; and (5) entering the extraction-iron removal-cobalt precipitation production process after redissolving. This invention proposes a three-stage neutralization method, which removes most of the impurities from the first part of the copper-cobalt raffinate and effectively enriches the valuable metal elements copper and cobalt in the third-stage neutralization slag, thereby improving the purity of the solution entering the iron removal-cobalt precipitation process and providing favorable conditions for the production of high-quality cobalt hydroxide. On the other hand, by using low-grade copper-cobalt oxide ore instead of lime slurry as an alkaline agent for the first-stage neutralization and utilizing sulfuric acid from the third-stage neutralization slag and the second part of the copper-cobalt raffinate, the cost of reagents such as lime alkaline agent and sulfuric acid is saved, and the copper and cobalt in the low-grade copper-cobalt oxide ore are also efficiently recovered and utilized.

[0103] Although this application has been described with reference to preferred embodiments, various modifications can be made thereto and components can be replaced with equivalents without departing from the scope of this application. In particular, the technical features mentioned in the various embodiments can be combined in any manner, provided there is no structural conflict. This application is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A method for recovering and producing high-quality cobalt hydroxide from copper- and cobalt-containing raffinate, characterized in that, Includes the following steps: The copper-cobalt raffinate is divided into two parts. The first part of the copper-cobalt raffinate is mixed and reacted with low-grade copper-cobalt oxide ore. The final pH value of the reaction is 1.2 to 2.

2. After the reaction is completed, the raffinate is separated into a bottom stream and an overflow stream. The bottom stream enters the leaching process, and the overflow stream enters the next step. The overflow is mixed with an alkaline agent and reacted. The final pH value of the reaction is 3.5-4.

2. After the reaction is completed, the mixture is separated into two underflows and two overflows. The two underflows enter the filter press process to obtain filter residue and the first filter liquid. The two overflows proceed to the next step. The resulting two-stage overflow and first-stage filtrate are mixed with an alkaline agent and reacted. The final pH value of the reaction is 6.2-7.

8. After the reaction is completed, the mixture is separated into three-stage underflow and three-stage overflow. The three-stage overflow is reused as a neutral water supply system. The three-stage underflow proceeds to the next step. The three-stage underflow and the second part of the copper-cobalt raffinate, as well as sulfuric acid, are redissolved, and the pH value at the reaction endpoint is controlled to be 3.5-4.

2. The solution is then filtered to obtain a redissolved residue and a second filtrate. The redissolved residue is washed and discharged. The second filtrate is extracted, iron removed and cobalt precipitated to obtain a cobalt-precipitated liquid and a cobalt hydroxide product. The second filtrate is subjected to extraction, iron removal and cobalt precipitation, which includes: the second filtrate is extracted to extract copper to obtain raffinate, then lime milk and oxidant are added to the raffinate to remove iron to obtain iron-removed liquid, and active magnesium oxide is added to the iron-removed liquid to precipitate cobalt to obtain cobalt-precipitated liquid and cobalt hydroxide product. The cobalt precipitation process consists of two stages. The first stage produces cobalt hydroxide, and then lime slurry is added to the liquid after the first stage cobalt precipitation for a second stage cobalt precipitation, resulting in a second-stage cobalt precipitation slag and a second-stage cobalt precipitation liquid. The second-stage cobalt precipitation slag is returned to the iron removal process, and the second-stage cobalt precipitation liquid is reused by the system.

2. The method for recovering and producing high-quality cobalt hydroxide from copper-cobalt raffinate according to claim 1, characterized in that, The copper-cobalt raffinate includes the raffinate formed after copper is initially extracted from copper-cobalt oxide ore during hydrometallurgical processes.

3. The method for recovering and producing high-quality cobalt hydroxide from copper-cobalt raffinate according to claim 2, characterized in that, The copper-cobalt raffinate includes high-copper-cobalt raffinate formed after the ore is leached with sulfuric acid in a copper-cobalt hydrometallurgical system and then extracted to extract copper, and low-copper-cobalt raffinate formed after the washing liquid from the ore leaching residue in a copper-cobalt hydrometallurgical system is washed and then extracted to extract copper.

4. The method for recovering and producing high-quality cobalt hydroxide from copper-cobalt raffinate according to claim 3, characterized in that, The first part of the copper-cobalt raffinate is mainly composed of low copper-cobalt raffinate.

5. The method for recovering and producing high-quality cobalt hydroxide from copper-cobalt raffinate according to claim 3, characterized in that, The two-part copper-cobalt raffinate is mainly composed of high-copper-cobalt raffinate.

6. The method for recovering and producing high-quality cobalt hydroxide from copper-cobalt raffinate according to claim 1, characterized in that, The low-grade copper-cobalt oxide ore includes flotation tailings, raw copper-cobalt oxide ore, or mineralized waste rock.

7. The method for recovering and producing high-quality cobalt hydroxide from copper-cobalt raffinate according to claim 1, characterized in that, The alkaline agent includes lime, limestone, sodium carbonate, or magnesium oxide.

8. The method for recovering and producing high-quality cobalt hydroxide from copper-cobalt raffinate according to claim 1, characterized in that, The resulting two-stage overflow and first pressure filtrate are mixed with an alkaline agent and reacted, with the final pH value being 6.8–7.2.

Images