A method for comprehensive recovery of valuable metals from nickel-cobalt sulfate solution containing copper and scandium

Abstract

The present invention belongs to the field of metallurgy technology, and specifically relates to a method for comprehensively recovering valuable metals from a nickel-cobalt sulfate solution containing copper and scandium, which comprises the following steps: (1) recovery of scandium: sodium sulfite is added to the nickel-cobalt sulfate solution containing copper and scandium, the end point pH is controlled to be 3.0-4.0, the reaction is stirred at 15-40°C, solid-liquid separation is performed, and scandium slag and a first nickel-cobalt sulfate solution are obtained; (2) recovery of copper: the first nickel-cobalt sulfate solution is heated to 45-95°C, a copper removal agent is added, the end point pH is controlled to be 3.0-5.0, the reaction is stirred, solid-liquid separation is performed, copper slag and a second nickel-cobalt sulfate solution are obtained; (3) recovery of nickel and cobalt: a neutralizing agent is added to the second nickel-cobalt sulfate solution, the end point pH is controlled to 8.5-9.5, solid-liquid separation is performed, nickel-cobalt precipitation liquid and nickel-cobalt slag are obtained, and nickel and cobalt are recovered from the nickel-cobalt slag. The method of the present invention can separate and obtain high-grade copper and scandium products, and simultaneously recover nickel and cobalt respectively.

Description

Technical Field

[0001] The invention belongs to the technical field of metallurgy, and in particular relates to a method for comprehensively recovering valuable metals from a nickel-cobalt sulfate solution containing copper and scandium. Background Art

[0002] The extraction of scandium mainly involves extracting or recovering scandium from some intermediate products and by-products. So far, people have divided the extraction methods of scandium into three types: extracting scandium from primary minerals, recovering scandium from industrial waste slag, and recovering scandium from industrial waste liquid. When hydrometallurgy is used to treat ores containing associated scandium, scandium and target elements are leached. After the target elements are recovered, scandium is discharged with the waste liquid. Therefore, industrial waste liquid is also a source of raw materials for recovering scandium. Hydrometallurgy is the main method for refining scandium. At present, the process for refining scandium is relatively simple. Improving the leaching rate and reducing the cost of extracting scandium are the main directions for extracting scandium in the future. Therefore, optimizing the scandium resource recovery process and reducing production costs are of great significance to the effective utilization of scandium resources.

[0003] Nickel-cobalt ore is a high-value scandium-containing resource. It is generally believed that the scandium content in the nickel-cobalt hydroxide intermediate reaches 20g / t, which is worth recovering. Scandium exists in the form of ions in the nickel-cobalt hydroxide intermediate. The nickel and cobalt therein are often converted into salts or electrolytic products by hydrometallurgy. The following methods are often used in hydrometallurgy to recover valuable metals: nickel and cobalt are first leached with inorganic acid. The leachate often contains a small amount of impurities such as silicon, copper, calcium, manganese, and zinc (leached together with nickel and cobalt). Silicon is often removed by chemical precipitation, and manganese, copper, and zinc are usually removed by extraction. In the process of silicon removal, most of the copper and scandium are also enriched with silicon into the silicon removal slag, accompanied by a small amount of nickel and cobalt loss. In order to improve the recovery rate of valuable metals, it is often necessary to Secondary recovery of nickel and cobalt in the silicon removal slag: first add a leaching agent to dissolve the nickel and cobalt therein, and then continue to remove impurities from the leaching solution. The commonly used methods for recovering or removing scandium from nickel cobalt sulfate solution in the prior art are one or more of extraction, resin adsorption, and precipitation. The most commonly used method is to enrich scandium with a resin or an extractant, and then desorb or strip it, respectively, and add a precipitant to the desorbed liquid or the stripped liquid. The commonly used scandium precipitants are hydroxides, fluorides, oxalates, and carbonates. The precipitate is then calcined to prepare scandium oxide. However, the extraction method and the resin adsorption method are usually only used to treat situations with low scandium concentrations, and the washing, stripping, and regeneration of the extractant and the adsorption, desorption, and regeneration cycles of the resin are relatively long, and the treatment efficiency is low. The invention provides a method for comprehensively recovering valuable metals from a nickel-cobalt sulfate solution containing copper and scandium. The method has the advantages of short process, simple operation, high recovery rates of scandium and copper, and the obtained scandium slag has high value. Copper can be separated alone, and the nickel and cobalt after separation of copper and scandium can continue to produce nickel salt / cobalt salt and electrolytic nickel / electrolytic cobalt respectively, thereby realizing full recovery of valuable metals. Summary of the invention

[0004] The present invention aims to solve the above technical problems and provides a method for comprehensively recovering valuable metals from a nickel-cobalt sulfate solution containing copper and scandium. The method can separate high-grade copper and scandium products, and simultaneously recover nickel and cobalt separately.

[0005] The technical solution of the present invention is:

[0006] A method for comprehensively recovering valuable metals from a nickel-cobalt sulfate solution containing copper and scandium comprises the following steps:

[0007] (1) Recovery of scandium: adding sodium sulfite to the nickel-cobalt sulfate solution containing copper and scandium, controlling the end point pH to 3.0-4.0, stirring the reaction at 15-40° C., and performing solid-liquid separation to obtain scandium slag and the first nickel-cobalt sulfate solution;

[0008] (2) Recovery of copper: the first nickel cobalt sulfate solution is heated to 45-95° C., a copper removal agent is added, the end point pH is controlled to be 3.0-5.0, the reaction is stirred, and the solid-liquid separation is performed to obtain copper slag and a second nickel cobalt sulfate solution;

[0009] (3) Recovery of nickel and cobalt: A neutralizing agent is added to the second nickel and cobalt sulfate solution, and the end point pH is controlled to 8.5-9.5. The solid and liquid are separated to obtain a nickel and cobalt precipitation liquid and a nickel and cobalt slag, and the nickel and cobalt are recovered.

[0010] Preferably, in step (1) of the present invention, the nickel cobalt sulfate solution containing copper and scandium contains Sc 3+ 0.1-20g / L, Cu 2+ 0.1-50g / L, pH 2.5-3.5. In step (1) of the present invention, sodium sulfite and scandium ions undergo double decomposition reaction:

[0011] 3SO 3 2- +2Sc 3+ =Sc 2 (SO 3 ) 3 (s) Formula (1-1)

[0012] After many experimental demonstrations, it was found that in the nickel cobalt sulfate solution system, when the temperature is lower than 40°C, the above reaction occurs to generate precipitated scandium sulfite, but when the temperature reaches above 45°C, basically no reaction occurs, but at this time the copper ions in the solution are removed to generate a reddish-brown cuprous oxide precipitate.

[0013] In the process of recovering copper and scandium, when the end point pH is too low, sulfur dioxide is easily generated after sodium sulfite is added, which reduces the utilization rate of sodium sulfite. When the pH exceeds 4.0, the hydrolysis reaction of copper ions, the hydrolysis reaction of sodium sulfite, and the reaction of scandium ions and sodium sulfite are all in progress, which will lead to incomplete separation of scandium and copper, and fail to achieve the purpose of extracting scandium and copper separately. Therefore, in order to ensure the grade of scandium slag, when recovering scandium, the pH should be controlled at 3.0-4.0, and the temperature should be controlled at 15-40°C. At this time, copper is basically not hydrolyzed, and copper and other metal ions do not react with sodium sulfite, and only scandium sulfite precipitation is generated.

[0014] Preferably, in step (2) of the present invention, the copper removal agent is one of sodium carbonate, sodium hydroxide, lime milk, calcium oxide, sodium sulfite, and sodium bisulfite. When sodium carbonate, sodium hydroxide, lime milk, and calcium oxide are used as the copper removal agent, the copper recovery process mainly undergoes a copper hydrolysis reaction. At this time, in order to ensure that the copper is completely precipitated, the pH should be controlled at 4.0-5.0. When the pH is lower than 4.0, the copper is not completely hydrolyzed. When the pH is higher than 5.0, the consumption of the copper removal agent will increase, and other impurities will also be hydrolyzed and precipitated together with the copper. Moreover, as the pH further increases, some nickel and cobalt ions will also be precipitated together with the copper removal process, thereby reducing the recovery rate of nickel and cobalt. Therefore, the copper removal pH should be controlled at 4.0-5.0 at this time. Combining the optimal conditions of the above two types of copper removers, the copper removal pH should be controlled at 3.0-5.0. When the copper remover is sodium sulfite or sodium bisulfite, the pH should be no less than 3.0 and no more than 4.3. When sodium carbonate, sodium hydroxide, lime milk, and calcium oxide are used as copper removers, the pH should be no less than 4.0 and no more than 5.0.

[0015] Preferably, when the copper removal agent is sodium sulfite or sodium bisulfite, the order of step (1) and step (2) can be interchanged, wherein the excess coefficient of sodium sulfite or sodium bisulfite is 1.5-4.0. The main reason why sodium sulfite removes scandium but does not remove copper under relatively low temperature conditions and removes copper but does not remove scandium under relatively high temperature is that: the hydrolysis degree of copper ions is relatively low at relatively low temperatures, and is basically not hydrolyzed, while the reaction of sodium sulfite with scandium ions is an exothermic reaction, so the reaction is easier to carry out at relatively low temperatures, and as the reaction temperature increases, the hydrolysis degree of sodium sulfite and copper ions increases, and at the same time, a reaction of sodium sulfite or sodium bisulfite with copper ions to generate cuprous oxide also occurs, and since the reaction of scandium with sodium sulfite is exothermic, when the temperature is increased, the reaction is suppressed. Therefore, by controlling the reaction temperature, the reaction of scandium with sodium sulfite and the reaction of sodium sulfite or sodium bisulfite with copper can be completely separated and carried out, thereby achieving the purpose of recovering copper and scandium respectively. Since the pH change caused by the reaction of sodium sulfite with scandium or copper is small, it is necessary to pre-control the pH of the nickel cobalt sulfate solution to 2.5-3.5. If the pH is lower than 2.5, the amount of sodium sulfite needs to be increased to achieve the effect of recovering copper and scandium respectively. If the pH is higher than 3.5, after the copper removal agent is added, the hydrolysis of sodium sulfite and copper ions in the solution will play a dominant role when recovering scandium, resulting in incomplete separation of scandium and copper, that is, copper is converted into copper hydroxide when scandium is precipitated, thereby reducing the grade of the scandium slag.

[0016] In step (2) of the present invention, when the reaction temperature is 45-95° C. and sodium sulfite or sodium bisulfite is used as the copper removal agent, the following redox reactions occur respectively:

[0017] SO 3 2- +2H 2 O+2Cu 2+ =Cu 2 O(s)+4H + +SO 4 2- Formula (1-2)

[0018] HSO 3 - +2H 2 O+2Cu 2+ =Cu 2 O(s)+5H + +SO 4 2- Formula (1-3)

[0019] When sodium sulfite or sodium bisulfite is used as the copper removal agent, the pH should be controlled at 3.0-4.3, and the temperature should be controlled at 45-95°C. At this time, the nickel cobalt sulfate solution does not contain scandium or mainly because of the temperature control, scandium does not react with sodium sulfite or sodium bisulfite, and other metal ions do not hydrolyze or precipitate under this condition. The precipitation reaction of sodium sulfite or sodium bisulfite with copper plays a dominant role to generate cuprous oxide precipitate, thereby achieving the separation of copper and scandium.

[0020] In the scandium recovery process, without adding a neutralizing agent, in step (1) of the present invention, when the amount of sodium sulfite added is 1.5-10 times the theoretical amount, the system pH does not increase significantly. When the amount of sodium sulfite is less than 1.5 times the theoretical amount, although the sodium sulfite does not react with metal ions other than copper and scandium in the solution, the precipitation of scandium is incomplete, and the scandium recovery rate is less than 50%. When the amount of sodium sulfite is higher than 10 times the theoretical amount, the excess sodium sulfite mainly undergoes a hydrolysis reaction, the system pH gradually increases, and at the same time, it also consumes part of the hydrogen ions generated by the hydrolysis of copper ions, further promoting the forward hydrolysis process of copper ions, which will result in a higher copper content in the scandium slag and incomplete separation of copper and scandium:

[0021] SO 3 2- +2H 2 O=HSO 3 - +OH - , HSO 3 -- +2H 2 O=H 2 SO 3 +OH - Formula (1-4)

[0022] Cu 2+ +2H 2 O=Cu(OH) 2 (s)+2H + Formula (1-5)

[0023] In particular, when sodium sulfite or sodium bisulfite is used as a copper removal agent to recover copper, copper and scandium can be extracted separately by controlling different temperatures, and the reactions of the two do not interfere with each other. Therefore, the recovery of copper and the recovery of scandium in step (1) and step (2) can be exchanged in order. However, when sodium carbonate, sodium hydroxide, lime milk, and calcium oxide are used as copper removal agents, due to the control of a relatively high pH (4.0-5.0), if the nickel cobalt sulfate solution before copper removal still contains scandium ions, the scandium ions will also undergo a hydrolysis reaction to generate scandium hydroxide, resulting in a higher precipitation rate of scandium when copper is recovered, reducing the grade of the copper slag, and incomplete separation of scandium and copper.

[0024] To ensure that copper is completely precipitated, when sodium sulfite or sodium bisulfite is used as a copper removal agent, the appropriate amount of copper removal agent should be controlled. When the excess coefficient of sodium sulfite or sodium bisulfite is less than 1.5, the copper precipitation rate is less than 30%. When the excess coefficient is higher than 4.0, the copper is completely precipitated. Due to the excessive addition of copper removal agent and the high reaction temperature, the hydrolysis degree of scandium will increase, and the separation of copper and scandium is not complete, which reduces the grade of copper slag. When the excess coefficient of sodium sulfite or sodium bisulfite is 1.5-4.0, the copper is completely precipitated, and the scandium, nickel and cobalt ions are not hydrolyzed, and no precipitation is generated. Therefore, the excess coefficient of sodium sulfite or sodium bisulfite should be controlled at 1.5-4.0 during copper recovery.

[0025] Preferably, in steps (1) and (2) of the present invention, the stirring reaction time is 1-4 h.

[0026] In step (3) of the present invention, the neutralizing agent of the present invention is preferably one of sodium hydroxide, sodium carbonate, lime milk, and calcium oxide. Step (3) is a nickel-cobalt precipitation process, and the pH is controlled to 8.5-9.5 to substantially completely convert the nickel-cobalt in the solution into nickel-cobalt hydroxide or nickel-cobalt carbonate.

[0027] Preferably, in step (3) of the present invention, the nickel-cobalt slag is treated by adding water to the nickel-cobalt slag to prepare pulp, and there is no strict requirement for the amount of water added. The pulping water can be easily stirred, and the temperature is raised to 50-95° C., and concentrated sulfuric acid is added. The end point pH is controlled to 1.0-2.5 so that the nickel and cobalt therein can be completely leached. The acid dissolution time is 1-4 hours. After the acid dissolution is completed, the solid and liquid are separated to obtain a first nickel-cobalt leaching solution, and then the nickel and cobalt are recovered from the first nickel-cobalt leaching solution.

[0028] Preferably, in step (3) of the present invention, the nickel-cobalt precipitation liquid is treated: the nickel-cobalt precipitation liquid is subjected to aeration oxidation, and the end point pH is controlled to 9.5-10.0 for two-stage nickel-cobalt precipitation, solid-liquid separation is performed to obtain the second-stage nickel-cobalt precipitation liquid and the second-stage nickel-cobalt precipitation slag, the second-stage nickel-cobalt precipitation slag is washed and acid-soluble leached to obtain a second nickel-cobalt leaching solution, and nickel and cobalt are recovered from the second nickel-cobalt leaching solution. Specifically, the pH of the nickel-cobalt precipitation solution is adjusted to 9.5-10.0 for two-stage nickel-cobalt precipitation, and the remaining small amount of nickel-cobalt ions can be converted into hydroxides or carbonates or sulfate precipitates. The reducing substances therein can be removed by aeration oxidation, and the oxidation process of the sulfite and bisulfite ions introduced in excess in the early stage can be accelerated to convert them into sulfate ions. The second-stage nickel-cobalt precipitation liquid can be used to produce sodium sulfate by-products, and then further treat wastewater. The main reactions occurring during aeration oxidation are:

[0029] 2SO 3 2- +O 2 =2SO 4 2- Formula (1-6)

[0030] 2HSO 3 - +2OH - +O 2 =2SO 4 2- +2H 2 O formula (1-7)

[0031] Preferably, the steps of recovering nickel and cobalt from the nickel-cobalt leachate of the present invention are: removing silicon by chemical precipitation, deep impurity removal by P204 extraction, and separating nickel and cobalt by C272 or P507 extraction to obtain a refined nickel salt or cobalt salt solution. Specifically, the nickel and cobalt contained in the nickel-cobalt leachate obtained after washing and acid dissolution of the nickel-cobalt precipitated slag can be separated by extraction by P507 or C272, for example: the nickel-cobalt leachate can be pre-impurified by chemical precipitation, the pH is adjusted to 4.5-6.0 to remove impurities, the impurity-removed liquid is extracted by P204, the P204 raffinate mainly contains nickel and cobalt, and then cobalt is extracted by P507 or C272, while nickel is left in the raffinate, the raffinate is deoiled to be a refined nickel sulfate solution, which can be used to produce nickel salts or electrolytic nickel, and the P507 or C272 after cobalt extraction is stripped of cobalt with an inorganic acid (such as hydrochloric acid, sulfuric acid), and the stripped cobalt solution can be used to produce cobalt salts or electrolytic cobalt.

[0032] Due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0033] 1. The method of the present invention can separate high-grade copper and scandium products from a nickel-cobalt sulfate solution containing copper and scandium, and simultaneously recover nickel and cobalt respectively.

[0034] 2. In the method of the present invention, scandium can be completely separated from nickel, cobalt and copper ions through the reaction of sodium sulfite and scandium. The purity of the obtained scandium sulfite precipitate reaches more than 94%, and the precipitation rate of scandium reaches more than 98%, without affecting the full recovery of copper, nickel and cobalt.

[0035] 3. In the method of the present invention, the reaction temperature is controlled to separate the reactions of sodium sulfite, copper and scandium, so that they do not interfere with each other and do not affect the purity of the recovered products and the recovery rates of scandium and copper. Among them, the recovery rate of copper is over 97%, and the purity of cuprous oxide is over 94%. The purity of other copper-containing products, such as copper carbonate and copper hydroxide, can also reach over 91%.

[0036] 4. In the method of the present invention, a neutralizing agent is added to the nickel-cobalt sulfate solution from which copper and scandium have been recovered, so that nickel and cobalt are completely converted into carbonate or hydroxide precipitates, and then the nickel-cobalt ions are acid-dissolved, washed, and leached, and the nickel-cobalt recovery rate is above 99%.

[0037] 5. In the method of the present invention, nickel and cobalt are finally separated by chemical precipitation to remove impurities, P204 extraction to remove impurities, P507 or C272 extraction to separate nickel and cobalt, so as to achieve the effect of separately recovering nickel and cobalt. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 The present invention provides a flow chart for the comprehensive recovery of valuable metals from a nickel-cobalt sulfate solution containing copper and scandium.

[0039] Figure 2 This is a nickel-cobalt recovery flow chart of the present invention. DETAILED DESCRIPTION

[0040] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0041] Example 1

[0042] (1) Recovery of Scandium: 1 L of the No. 1 nickel-cobalt sulfate solution was added to the solution at 15° C. Industrial sodium sulfite with a purity of 82% was added thereto in an amount of 4.96 times the excess coefficient of the sodium sulfite in the reaction with scandium. After stirring for 1 h, the solution was filtered to obtain scandium residue and the first nickel-cobalt sulfate solution (the components are shown in Table 3). The scandium residue was dried at a constant temperature of 105° C. The dry weight was 0.37 g. After testing, the scandium residue contained 26.65% scandium and 71.78% sulfite. The Sc content was 1. 2 (SO 3 ) 3 The purity is 97.73%, the copper content is only 0.015%, the nickel and cobalt content are both less than 0.001%, and the precipitation rate of scandium is 98.61%;

[0043] (2) Recovery of copper: 0.8 L of the first nickel cobalt sulfate solution obtained in step (1) was taken, heated to 45° C., and then industrial sodium sulfite with a purity of 82% was added. The amount of sodium sulfite was 4 times the excess coefficient of its reaction with copper. After stirring for 2 h, 3.32 g of copper slag and a second nickel cobalt sulfate solution (the components are shown in Table 5) were obtained by filtering. After testing, the copper slag contained 85.22% copper, the nickel and cobalt contents were both less than 0.001%, and the Cu 2 O purity 95.87%, copper precipitation rate 98.51%;

[0044] (3) Recovery of nickel and cobalt: Since the nickel and cobalt content in the second nickel and cobalt sulfate solution is relatively low, it enters the nickel and cobalt precipitation process (adding 10% by mass caustic soda) together with the nickel and cobalt sulfate solutions with higher nickel and cobalt ions in other existing production systems for two-stage nickel and cobalt precipitation, wherein the endpoint pH of the first stage is controlled to be 9.25, to obtain a first stage nickel and cobalt precipitation liquid and a first stage nickel and cobalt precipitation slag, to which 10% by mass caustic soda is further added to control the endpoint pH to 9.88, and air is introduced to oxidize the reducing substances therein at the same time, and aeration oxidation is performed for 4 hours to obtain a nickel and cobalt precipitation oxidation liquid and a second stage nickel and cobalt precipitation slag, wherein the nickel concentration in the nickel and cobalt precipitation oxidation liquid is less than 1 mg / L, the copper and scandium concentrations are both less than 0.1 mg / L, the cobalt concentration is less than 0.5 mg / L, and the sulfite ion concentration is less than 50 mg / L, water is added to the second stage nickel and cobalt precipitation slag to prepare a slurry, the slurry liquid-to-solid mass ratio is 1:1, and sulfuric acid is added to obtain a nickel and cobalt leaching solution. (acid dissolution temperature 50 ° C, time 1h, pH 2.50), the leaching rates of nickel and cobalt both reached more than 99%, limestone powder was added to the nickel-cobalt leaching solution to remove silicon (control the end point pH 4.50), 25% volume concentration of P204 was used for deep extraction and impurity removal (the P204 raffinate contained less than 0.005g / L calcium and less than 0.001g / L manganese), and 15% volume concentration of P507 was used to extract cobalt, and the P507 raffinate contained 90-120g nickel / L, cobalt is less than 0.001g / L, to obtain a refined nickel sulfate solution, the P507 after cobalt extraction is stripped with 3N sulfuric acid, the pH of the stripping solution is controlled to 2.50, to obtain a refined cobalt sulfate solution, the cobalt sulfate solution contains 80-100g / L of cobalt, and nickel is less than 0.1g / L. The above nickel sulfate and cobalt sulfate solutions can be used to produce nickel sulfate crystals or electrolytic nickel, cobalt sulfate crystals or electrolytic cobalt, respectively. The specific nickel and cobalt recovery conditions and results are shown in Tables 6 and 7.

[0045] Example 2

[0046] (1) Recovery of Scandium: 5 L of 2# nickel-cobalt sulfate solution was added to the solution at 40°C with industrial sodium sulfite having a purity of 82%. The amount of sodium sulfite added was 10 times the excess coefficient of the sodium sulfite reaction with scandium. After stirring for 2 h, the solution was filtered to obtain scandium residue and the first nickel-cobalt sulfate solution (the composition is shown in 3). The scandium residue was dried at 105°C to a dry weight of 6.0 g. After testing, the scandium residue contained 27% scandium and 72.22% sulfite. 2 (SO 3 ) 3 The final purity is 99.01%, the copper content is only 0.026%, the nickel and cobalt content are both less than 0.001%, and the precipitation rate of scandium is as high as 98.18%;

[0047] (2) Recovery of copper: 4.85 L of the first nickel cobalt sulfate solution obtained in step (1) was taken, heated to 95° C., and then industrial sodium sulfite with a purity of 82% was added. The amount of sodium sulfite added was 1.5 times the excess coefficient of its reaction with copper. After stirring and reacting for 4 hours, 56.9 g of copper slag and a second nickel cobalt sulfate solution (the components are shown in Table 5) were obtained by filtering. After testing, the copper slag contained 84.25% copper, the nickel and cobalt contents were both less than 0.001%, and the Cu 2 O purity is 94.78%, copper precipitation rate is 98.84%;

[0048] (3) Recovery of nickel and cobalt: A neutralizing agent is added to the second nickel cobalt sulfate solution to enter the nickel cobalt precipitation process: lime milk is added to carry out two-stage nickel cobalt precipitation, wherein the endpoint pH of the first stage is controlled to be 8.77, to obtain a first stage nickel cobalt precipitation liquid and a first stage nickel cobalt precipitation slag, lime milk is continued to be added to the first stage nickel cobalt precipitation liquid, the endpoint pH of the second stage nickel cobalt precipitation is controlled to be 9.55, and air is introduced to oxidize the reducing substances therein, and aeration oxidation is performed for 4 hours to obtain a nickel cobalt precipitation oxidation liquid and a second stage nickel cobalt precipitation slag, the nickel concentration in the nickel cobalt precipitation oxidation liquid is less than 1 mg / L, the copper and scandium concentrations are both less than 0.1 mg / L, the cobalt concentration is less than 0.5 mg / L, and the sulfite ion concentration is less than 50 mg / L, water is added to the nickel cobalt precipitation slag to make a pulp, the pulping liquid-to-solid mass ratio is 0.5:1, sulfuric acid is added for acid leaching to obtain a nickel cobalt leaching solution (acid dissolution temperature 95°C, time 1 h, pH1.50), the leaching rates of nickel and cobalt both reached more than 99%, limestone powder was added to the nickel-cobalt leaching solution to remove silicon (control the end point pH4.89), P204 with a volume concentration of 25% was extracted for deep impurity removal (the P204 raffinate contained less than 0.005g / L calcium and less than 0.001g / L manganese), and C272 with a volume concentration of 15% was used to extract cobalt. The C272 raffinate contained 90-120g / L nickel and less than 0.001g / L cobalt to obtain a refined nickel sulfate solution. The C272 after cobalt extraction was stripped with 4N sulfuric acid, and the pH of the stripping solution was controlled to 3.51 to obtain a refined cobalt sulfate solution. The cobalt sulfate solution contained 80-100g / L cobalt and less than 0.1g / L nickel. The above nickel sulfate and cobalt sulfate solutions can be used to produce nickel sulfate crystals or electrolytic nickel, cobalt sulfate crystals or electrolytic cobalt, respectively. The specific nickel and cobalt recovery conditions and results are shown in Tables 6 and 7.

[0049] Example 3

[0050] (1) Recovery of Scandium: 500 L of 3# nickel-cobalt sulfate solution was taken, and industrial sodium sulfite with a purity of 82% was added thereto at 30°C. The amount of sodium sulfite added was 1.51 times the excess coefficient of the sodium sulfite reaction with scandium. After stirring for 2 hours, the scandium slag and the first nickel-cobalt sulfate solution (the components are shown in Table 3) were obtained by filtration. The scandium slag was dried at a constant temperature of 105°C, and the dry weight was 37 kg. After testing, the scandium slag contained 26.60% scandium and 71.65% sulfite. The Sc2 (SO 3 ) 3 The purity is 97.54%, the copper content is only 0.020%, the nickel and cobalt content are both less than 0.001%, and the precipitation rate of scandium is 98.42%;

[0051] (2) Recovery of copper: 499 L of the first nickel-cobalt sulfate solution obtained in step (1) was taken, heated to 55° C., and then industrial sodium sulfite with a purity of 82% was added. The amount of sodium sulfite added was 2.51 times the excess coefficient of its reaction with copper. After stirring for 1 hour, 8.93 kg of copper slag and a second nickel-cobalt sulfate solution (the composition is shown in Table 5) were obtained by filtering. After testing, the copper slag contained 84.59% copper, the nickel and cobalt contents were both less than 0.001%, and the Cu 2 O purity is 95.16%, copper precipitation rate is 99.07%;

[0052] (3) Recovery of nickel and cobalt: A neutralizing agent is added to the second nickel cobalt sulfate solution to enter the nickel cobalt precipitation process: Lime milk is added to carry out two-stage nickel cobalt precipitation, wherein the endpoint pH of the first stage is controlled to be 9.49, to obtain a first stage nickel cobalt precipitation liquid and a first stage nickel cobalt precipitation slag, lime milk is continued to be added to the first stage nickel cobalt precipitation liquid, the endpoint pH of the second stage nickel cobalt precipitation is controlled to be 10.00, and air is introduced to oxidize the reducing substances therein, and aeration oxidation is performed for 8 hours to obtain a nickel cobalt precipitation oxidation liquid and a second stage nickel cobalt precipitation slag, the nickel concentration in the nickel cobalt precipitation oxidation liquid is less than 1 mg / L, the copper and scandium concentrations are both less than 0.1 mg / L, the cobalt concentration is less than 0.5 mg / L, and the sulfite ion concentration is less than 50 mg / L, water is added to the nickel cobalt precipitation slag to make a pulp, the pulping liquid-to-solid mass ratio is 0.8:1, sulfuric acid is added for acid leaching to obtain a nickel cobalt leaching solution (acid leaching temperature 60°C, time 2 h, pH1.00), the leaching rates of nickel and cobalt both reached more than 99%, limestone powder was added to the nickel-cobalt leaching solution to remove silicon (control the end point pH5.00), P204 with a volume concentration of 25% was extracted for deep impurity removal (the P204 raffinate contained less than 0.005g / L calcium and less than 0.001g / L manganese), and C272 with a volume concentration of 15% was used to extract cobalt. The C272 raffinate contained 90-120g / L nickel and less than 0.001g / L cobalt to obtain a refined nickel sulfate solution. The C272 after cobalt extraction was stripped with 3.5N sulfuric acid, and the pH of the stripping solution was controlled to 2.63 to obtain a refined cobalt sulfate solution. The cobalt sulfate solution contained 80-100g / L cobalt and less than 0.1g / L nickel. The above nickel sulfate and cobalt sulfate solutions can be used to produce nickel sulfate crystals or electrolytic nickel, cobalt sulfate crystals or electrolytic cobalt, respectively. The specific nickel and cobalt recovery conditions and results are shown in Tables 6 and 7.

[0053] Example 4

[0054] (1) Recovery of Scandium: 100 L of 4# nickel sulfate solution was added to the solution at 30°C with industrial sodium sulfite having a purity of 82%. The amount of sodium sulfite added was 6.22 times the excess coefficient of the sodium sulfite reaction with scandium. After stirring for 4 h, the solution was filtered to obtain scandium slag and the first nickel cobalt sulfate solution (the components are shown in Table 3). The scandium slag was dried at 105°C with a dry weight of 462 g. After testing, the scandium slag contained 25.68% scandium and 69.17% sulfite. 2 (SO 3 ) 3 The purity is 94.17%, the copper content is only 0.034%, the cobalt content is less than 0.001%, and the precipitation rate of scandium is as high as 98.87%;

[0055] (2) Recovery of copper: 99.5 L of the first nickel sulfate solution obtained in step (1) was taken, heated to 60° C., and then sodium bisulfite with a purity of 99.5% was added. The amount of sodium bisulfite added was 1.5 times the excess coefficient of its reaction with copper. After stirring for 2 h, 2.65 kg of copper slag and a second nickel cobalt sulfate solution (the composition is shown in Table 5) were obtained by filtering. After testing, the copper slag contained 85.02% copper, less than 0.001% nickel, and Cu. 2 O purity is 95.65%, copper precipitation rate is 98.06%;

[0056] (3) Recovery of nickel: A neutralizing agent is added to the second nickel sulfate solution to enter the nickel precipitation process: a sodium carbonate solution with a mass concentration of 15% is added to carry out two-stage nickel precipitation, wherein the endpoint pH of the first stage is controlled to be 8.50, to obtain a first stage nickel precipitation liquid and a first stage nickel precipitation slag, and a sodium carbonate solution with a mass concentration of 15% is continued to be added to the first stage nickel precipitation liquid to control the endpoint pH of the second stage nickel precipitation to be 9.62, and air is introduced to oxidize the reducing substances therein, and aeration oxidation is carried out for 12 hours to obtain a nickel precipitation oxidation liquid and a second stage nickel precipitation slag, wherein the concentrations of copper and scandium in the nickel precipitation oxidation liquid are both lower than 0.1 mg / L, the concentration of nickel is lower than 0.5 mg / L, and the concentration of sulfite is lower than 0. The concentration of acid radical ions is lower than 50 mg / L. Water is added to the nickel precipitate slag to make pulp. The pulping liquid-to-solid mass ratio is 1.5:1. Sulfuric acid is added to obtain nickel leaching solution (acid dissolution temperature 55°C, time 4h, pH 2.22). The leaching rate of nickel reaches more than 99%. Limestone powder is added to the nickel leaching solution to remove silicon (control the end point pH 5.50), and P204 with a volume concentration of 25% is extracted to remove impurities (P204 raffinate contains less than 0.005g / L calcium and less than 0.001g / L manganese). Refined nickel sulfate solution is obtained. The nickel sulfate solution contains 80-100g / L nickel and can be used to produce nickel sulfate crystals or electrolytic nickel. The specific nickel recovery conditions and results are shown in Tables 6 and 7.

[0057] Example 5

[0058] (1) Recovery of scandium: Except that the precipitation time of scandium was 4 hours, other conditions were the same as those in Example 1; the compositions of the scandium slag and the first nickel-cobalt sulfate solution are shown in Table 3;

[0059] (2) Recovery of copper: 0.8 L of the first nickel cobalt sulfate solution obtained in step (1) was taken, heated to 45° C., and then a 10% mass concentration of liquid caustic soda was added to adjust the pH to 4.98. After a total reaction of 1 h, 4.55 g of copper slag and a second nickel cobalt sulfate solution (the components are shown in Table 5) were obtained by filtration. After testing, the copper slag contained 62.18% copper, Cu(OH) 2 Purity 95.2%, copper precipitation rate 98.51%;

[0060] (3) Recovery of nickel and cobalt: Same as in Example 1.

[0061] Example 6

[0062] (1) Recovery of scandium: Same as in Example 1, the compositions of the scandium slag and the first nickel cobalt sulfate solution are shown in Table 3;

[0063] (2) Recovery of copper: 0.8 L of the first nickel cobalt sulfate solution obtained in step (1) was taken, heated to 95° C., and then a sodium carbonate solution with a mass concentration of 15% was added to adjust the pH to 4.02. After the total reaction was carried out for 2 h, 6.04 g of copper slag and a second nickel cobalt sulfate solution (the components are shown in Table 5) were obtained by filtration. After testing, the copper slag contained 47.43% copper, CuCO 3 The purity is 91.9% and the copper precipitation rate is 99.75%.

[0064] (3) Recovery of nickel and cobalt: Same as in Example 1.

[0065] Example 7

[0066] (1) Recovery of copper: 15 L of 5# cobalt sulfate solution was heated to 45°C, and then industrial sodium sulfite with a purity of 82% was added thereto. The amount of sodium sulfite was 4 times the excess coefficient of its reaction with copper. After stirring for 4 hours, 7.6 g of copper slag and the first nickel cobalt sulfate solution (the composition is shown in Table 3) were obtained by filtration. The copper slag contained 84.29% copper, less than 0.001% cobalt, and only 0.022% scandium. 2 O purity is 94.83%, and the copper precipitation rate is as high as 97.06%;

[0067] (2) Recovery of Scandium: 14.85 L of the first cobalt sulfate solution obtained in step (1) was taken, and industrial sodium sulfite with a purity of 82% was continuously added at 15° C. The amount of sodium sulfite added was 1.51 times the excess coefficient of the sodium sulfite for the reaction with scandium. After stirring for 1 hour, the scandium slag and the second nickel cobalt sulfate solution (the components are shown in Table 5) were obtained by filtration. The scandium slag was dried at a constant temperature of 105° C. The dry weight was 5.5 g. After testing, the scandium slag contained 26.60% scandium, the cobalt content was less than 0.001%, and the Sc content was 1.3%. 2 (SO 3 ) 3 The purity is 97.54%, and the precipitation rate of scandium is 98.52%;

[0068] (3) Recovery of cobalt: A neutralizing agent is added to the second cobalt sulfate solution to enter the cobalt precipitation process, and calcium oxide is added to perform a cobalt precipitation step. The endpoint pH is controlled to be 9.51, and air is introduced to oxidize the reducing substances therein. The aeration oxidation is performed for 10 hours to obtain a cobalt precipitation oxidation liquid and a cobalt precipitation slag. The concentrations of copper and scandium in the cobalt precipitation oxidation liquid are both lower than 0.1 mg / L, the concentration of cobalt is lower than 0.5 mg / L, and the concentration of sulfite ions is lower than 50 mg / L. Water is added to the cobalt precipitation slag to prepare a pulp, and the pulping liquid-to-solid mass ratio is 2:1. Sulfuric acid is added to obtain a cobalt leaching slag. The leaching rate of cobalt reaches more than 99% in the solution (acid dissolution temperature 75°C, time 2h, pH 1.55). Limestone powder is added to the cobalt leaching solution to remove silicon (control the end point pH 4.72), and then cobalt is extracted with C272 with a volume concentration of 15% (the cobalt in the C272 raffinate is less than 0.001g / L). The C272 after cobalt extraction is stripped with 3.5N sulfuric acid, and the pH of the stripping solution is controlled to 3.09 to obtain a refined cobalt sulfate solution containing 80-100g / L of cobalt, which can be used to produce cobalt sulfate crystals or electrolytic cobalt. The specific cobalt recovery conditions and results are shown in Tables 6 and 7.

[0069] Example 8

[0070] (1) Recovery of copper: 50 L of 6# nickel-cobalt sulfate solution was heated to 95° C. and then sodium bisulfite with a purity of 99.5% was added thereto. The amount of sodium bisulfite added was 1.5 times the excess coefficient of its reaction with copper. After stirring for 1 h, 2.86 kg of copper slag and the first nickel-cobalt sulfate solution (the components are shown in Table 3) were obtained by filtering. After testing, the copper content was 85.37%, the nickel and cobalt content was less than 0.001%, and the scandium content was only 0.013%. Cu 2 O purity is 96.04%, and the copper precipitation rate is as high as 97.66%;

[0071] (2) Recovery of Scandium: 49.8 L of the first nickel-cobalt sulfate solution obtained in step (1) was added to industrial sodium sulfite with a purity of 82% at 40° C. The amount of sodium sulfite added was 6.18 times the excess coefficient of the sodium sulfite for the reaction with scandium. After stirring for 4 hours, the scandium slag and the second nickel-cobalt sulfate solution (the components are shown in Table 5) were obtained by filtration. The scandium slag was dried at a constant temperature of 105° C. The dry weight was 1.87 kg. After testing, the scandium slag contained 26.67% scandium, the nickel and cobalt contents were both less than 0.001%, and the Sc content was 1.87 kg. 2 (SO 3 ) 3 The purity is 97.80% and the precipitation rate of scandium is 98.67%.

[0072] (3) Recovery of nickel and cobalt: Same as in Example 1.

[0073] Table 1 Main components of nickel cobalt sulfate solution containing copper and scandium (unit: g / L)

[0074] serial number Application Examples Ni Co Cu Sc pH 1# 1、5、6 5.26 0.40 3.60 0.10 3.45 2# 2 80 6.62 10.00 0.33 3.50 3# 3 40.15 5.00 15.28 20.00 3.00 4# 4 65.64 0 23.11 1.20 2.50 5# 7 0 80.00 0.44 0.10 3.07 6# 8 12.32 0.066 50.00 0.10 3.50

[0075] Table 2 Recovery conditions of scandium (Examples 1-6) and copper (Examples 7-8) in step (1)

[0076]

[0077] Table 3 Main components of the first nickel cobalt sulfate solution and main components of the slag dry basis

[0078]

[0079] It can be seen from Tables 1 to 3 that from the changes in the composition of the first nickel cobalt sulfate solution and the original composition of the nickel cobalt sulfate solution containing copper and scandium in Examples 1-6, it can be seen that the scandium recovery process does not cause the loss of nickel and cobalt, and copper does not generate precipitation together with scandium, so the separation effect of scandium and copper, nickel and cobalt is better; from the changes in the composition of the first nickel cobalt sulfate solution and the original composition of the nickel cobalt sulfate solution containing copper and scandium in Examples 7-8, it can be seen that the copper recovery process does not cause the loss of cobalt, and scandium does not generate precipitation together with copper, so the separation effect of copper and scandium, nickel and cobalt is better.

[0080] Table 4 Recovery conditions of copper (Examples 1-6) and scandium (Examples 7-8) in step (2)

[0081]

[0082] Table 5 Main components of nickel-cobalt solution and copper slag after recovery of scandium and copper

[0083]

[0084] From Table 3 to Table 5, it can be seen that the composition changes of the second nickel cobalt sulfate solution composition and the first nickel cobalt sulfate solution composition in Examples 1-6 show that the copper recovery process does not cause the loss of nickel and cobalt, so the separation effect of copper from nickel and cobalt is good; from the composition changes of the second nickel cobalt sulfate solution composition and the first nickel cobalt sulfate solution composition in Examples 7-8, it can be seen that the scandium recovery process does not cause the loss of nickel and cobalt, so the separation effect of scandium from nickel and cobalt is good. In summary, it can be seen that the technical solution of the present invention can achieve the separation of copper and scandium while maintaining a high nickel and cobalt recovery rate.

[0085] Table 6 Nickel-cobalt recovery conditions (using a mixed solution containing nickel-cobalt sulfate ions as a nickel-cobalt precipitation pre-liquid)

[0086]

[0087] Table 7 Refining of nickel cobalt sulfate leaching solution

[0088]

[0089] As can be seen from Tables 6 and 7, a mixed solution containing nickel and cobalt sulfate ions is used as a pre-liquid for nickel and cobalt precipitation, a neutralizing agent is added to precipitate nickel and cobalt, and then the post-precipitation solution is aerated and oxidized, and the endpoint pH is controlled to 9.5-10.0 for two-stage nickel and cobalt precipitation, and solid-liquid separation is performed to obtain a second-stage nickel and cobalt precipitation post-liquid and a second-stage nickel and cobalt precipitation slag. The second-stage nickel and cobalt precipitation slag is washed, slurried with water, and then leached with sulfuric acid to obtain a second nickel and cobalt leaching solution. The nickel and cobalt leaching solution is subjected to chemical precipitation to remove silicon, P204 extraction to deeply remove impurities, and C272 or P507 extraction to separate nickel and cobalt to obtain a refined nickel salt or cobalt salt solution, so that nickel and cobalt can be separated, and the effect of recovering nickel and cobalt respectively can be achieved.

[0090] The above description is a detailed description of the preferred feasible embodiments of the present invention, but the embodiments are not intended to limit the scope of the patent application of the present invention. All equivalent changes or modified changes completed under the technical spirit suggested by the present invention should fall within the patent scope covered by the present invention.

Claims

1. A method for comprehensive recovery of valuable metals from nickel-cobalt sulfate solution containing copper and scandium, It is characterized in that The following steps are involved: (1) Recovery of scandium: adding sodium sulfite to the nickel-cobalt sulfate solution containing copper and scandium, controlling the end point pH to 3.0-4.0, stirring the reaction at 15-40° C., and performing solid-liquid separation to obtain scandium slag and the first nickel-cobalt sulfate solution; (2) Recovery of copper: the first nickel cobalt sulfate solution is heated to 45-95° C., a copper removal agent is added, the end point pH is controlled to be 3.0-5.0, the reaction is stirred, and the solid-liquid separation is performed to obtain copper slag and a second nickel cobalt sulfate solution; (3) Recovery of nickel and cobalt: A neutralizing agent is added to the second nickel and cobalt sulfate solution, and the end point pH is controlled to 8.5-9.

5. The solid and liquid are separated to obtain a nickel and cobalt precipitation liquid and a nickel and cobalt slag, and the nickel and cobalt are recovered.

2. The method for comprehensive recovery of valuable metals from a nickel-cobalt sulfate solution containing copper and scandium as claimed in claim 1, Features: In the step (1), the nickel cobalt sulfate solution containing copper and scandium contains Sc 3+ 0.1-20g / L, Cu 2+ 0.1-50g / L, pH2.5-3.

5.

3. The method for comprehensive recovery of valuable metals from nickel-cobalt sulfate solution containing copper and scandium as claimed in claim 1, Features: In the step (1), the excess coefficient of sodium sulfite is 1.5-10.

4. The method for comprehensive recovery of valuable metals from nickel-cobalt sulfate solution containing copper and scandium as claimed in claim 1, Features: In the step (2), the copper removal agent is one of sodium carbonate, sodium hydroxide, lime milk, calcium oxide, sodium sulfite, and sodium bisulfite.

5. The method for comprehensive recovery of valuable metals from nickel-cobalt sulfate solution containing copper and scandium as claimed in claim 1, Features: In the steps (1) and (2), the stirring reaction time is 1-4 hours.

6. The method for comprehensive recovery of valuable metals from nickel-cobalt sulfate solution containing copper and scandium as claimed in claim 1, Features: In the step (3), the neutralizing agent is one of sodium hydroxide, sodium carbonate, lime milk, and calcium oxide.

7. The method for comprehensive recovery of valuable metals from nickel-cobalt sulfate solution containing copper and scandium as claimed in claim 1, Features: In the step (3), the nickel-cobalt slag is treated by adding water to the nickel-cobalt slag to make a slurry, heating it to 50-95° C., adding concentrated sulfuric acid, controlling the end point pH to 1.0-2.5, and acid dissolving for 1-4 hours. After the acid dissolution is completed, the solid-liquid separation is performed to obtain a first nickel-cobalt leaching solution, and then recovering nickel and cobalt from the first nickel-cobalt leaching solution.

8. The method for comprehensive recovery of valuable metals from nickel-cobalt sulfate solution containing copper and scandium as claimed in claim 7, Features: In the step (3), the post-nickel-cobalt precipitation liquid is treated by aeration oxidation of the post-nickel-cobalt precipitation liquid, while controlling the endpoint pH to 9.5-10.0 to perform second-stage nickel-cobalt precipitation, solid-liquid separation to obtain second-stage nickel-cobalt precipitation liquid and second-stage nickel-cobalt precipitation slag, washing the second-stage nickel-cobalt precipitation slag, acid leaching to obtain a second nickel-cobalt leaching liquid, and then recovering nickel and cobalt from the second nickel-cobalt leaching liquid.

9. The method for comprehensive recovery of valuable metals from a nickel-cobalt sulfate solution containing copper and scandium as claimed in claim 7 or 8, Features: The steps of recovering nickel and cobalt from nickel-cobalt leaching solution are as follows: removing silicon by chemical precipitation, deep impurity removal by P204 extraction, and separation of nickel and cobalt by C272 or P507 extraction to obtain a refined nickel salt or cobalt salt solution.

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