Method for separating and recovering scandium from impurity P204 organic matter extracted from scandium-containing nickel-cobalt material

Abstract

The invention belongs to the technical field of nickel and cobalt wet refining, and particularly discloses a method for separating and recycling scandium from impurity P204 organic matter extracted from a scandium-containing nickel and cobalt material, the P204 organic matter after iron washing is mixed with a sodium hydroxide solution with the concentration of 1-1.2 mol / L and the phase ratio O / A of 1: (1-1.2), P204 saponification is completed in the mixing process, meanwhile, trace scandium loaded in the P204 organic matter can be reversely extracted, and the scandium content in the P204 organic matter can be recycled. Partial scandium in the saponification strip liquor is hydrolyzed into precipitates, and partial scandium is dissolved in the precipitates; after saponification, organic acidification is conducted till the saponification rate is 65% and then returns to an original production system, saponification strip liquor is heated to 95 DEG C, acetic acid is added for scandium precipitation, the addition amount of acetic acid is 1.0-1.2 times of the theoretical scandium precipitation amount, obtained precipitation residues are scandium acetate residues, sodium hydroxide is supplemented into the liquid obtained after precipitation, and then saponification circulation is conducted; the method is characterized in that a saponification mode of an original process is changed, saponification strip liquor is separated, scandium is precipitated, a scandium precipitation reagent has no influence on an original production system, sodium hydroxide is supplemented into liquor after scandium precipitation, then the liquor returns to the system for reuse, no three wastes are generated in the scandium recovery process, and the method is a clean scandium recovery process method.

Description

Technical Field

[0001] The present invention belongs to the technical field of nickel-cobalt hydrometallurgical refining, and particularly relates to a method for separating and recovering scandium from P204 organic containing scandium in nickel-cobalt materials. Background Art

[0002] Nickel-cobalt hydroxide materials are usually nickel-cobalt intermediate products obtained by the sulfuric acid high-pressure leaching process of laterite nickel ore. In laterite nickel ore, the scandium content is usually 50 - 600 g / t, and the scandium-containing components in laterite nickel ore from different regions vary greatly. During the process of producing nickel-cobalt hydroxide from laterite nickel ore by the sulfuric acid high-pressure leaching process, most of the scandium in the raw materials is enriched in the nickel-cobalt hydroxide product.

[0003] Nickel-cobalt hydroxide products produced from laterite nickel ore are mostly used in the production of nickel-cobalt sulfate salts or electrolytic nickel. The front-end processes of their production are the same, which are: reduction dissolution leaching of nickel-cobalt hydroxide - neutralization and iron-aluminum removal from the leaching solution - P204 extraction and impurity removal from the solution after iron-aluminum removal, and the solution after P204 impurity extraction enters the subsequent processes. After the scandium in the nickel-cobalt hydroxide material enters the leaching solution, since the pH at the end point of neutralization and iron-aluminum removal is mostly controlled at about 4.5, only a small amount of scandium enters the iron-aluminum slag, and a large amount of scandium follows the solution after iron-aluminum removal into the P204 extraction process.

[0004] The typical process flow of P204 impurity extraction is P204 sodium soap - P204 nickel soap - extraction - washing nickel from the loaded organic phase - washing copper and manganese from the loaded organic phase - washing iron from the loaded organic phase - saponification of the organic phase after iron washing (a complete organic cycle process). The scandium in the solution after iron-aluminum removal exists as Sc3+ ions in the solution. It has a strong binding ability with P204 organic, and once the scandium loaded on P204 organic is difficult to elute under acidic conditions, that is, the scandium loaded on P204 will not be back-extracted from the loaded P204 with subsequent processes such as P204 nickel washing, P204 copper and manganese washing, and iron washing, and the scandium is still loaded on the P204 organic phase. If a high-concentration hydrochloric acid is used for back-extracting scandium, the obtained back-extraction solution has a high acidity and is difficult to process; if an alkali solution is used for back-extracting, due to the amphoteric characteristics of scandium, part of the scandium dissolves in the back-extraction solution, and part of the scandium hydrolyzes into colloidal scandium hydroxide precipitate. The back-extraction solution is in a solid-liquid mixed state and needs to be acid-dissolved before further treatment, resulting in a large amount of acid and alkali consumption.

[0005] In most nickel-cobalt hydroxide refining enterprises, due to the low scandium content in the materials and the lack of economically viable recovery methods, most enterprises do not recover scandium separately. In actual production, the P204 organic after iron washing is saponified with 10 mol / L sodium hydroxide, and the saponification rate is controlled at 65%. After saponification, liquid-solid separation is not carried out, and the saponified organic and a small amount of aqueous solution enter the nickel soap process together. This leads to the continuous enrichment of scandium loaded on the P204 organic during production, resulting in a continuous decline in the organic extraction capacity until it finally fails and is discarded, ultimately causing the phenomenon of "scandium poisoning" of the organic. At the same time, the hydrolysis precipitation of scandium hydroxide formed during the saponification process will cause the formation of three-phase substances, increasing production costs and bringing great difficulties to production operations.

[0006] In view of the problems of difficult scandium recovery and the "poisoning" of P204 organic caused by scandium faced in the subsequent refining production process of the above nickel-cobalt hydroxide materials, the present invention proposes a brand-new method for recovering scandium from the P204-loaded organic in the nickel-cobalt hydroxide materials with clean and pollution-free. Summary of the Invention

[0007] The object of the present invention is to provide a method for separating and recovering scandium from the P204 organic in nickel-cobalt materials containing scandium. Aiming at the problem of difficult scandium recovery in the production process of treating the intermediate product nickel-cobalt hydroxide materials produced by the laterite ore pressure acid leaching process, a scandium recovery process is added to the P204 extraction process to realize the recovery and utilization of scandium metal resources in laterite ore, and solve the problem that scandium loaded on the P204 organic cannot be back-extracted and causes organic poisoning during the repeated recycling of the P204 organic in the nickel-cobalt hydroxide material treatment process. There is no waste water and waste residue discharge in the whole process.

[0008] In order to achieve the above object, the technical solution adopted by the present invention is as follows: A method for separating and recovering scandium from the P204 organic in nickel-cobalt materials containing scandium, comprising the following steps: Step 1: Mix the P204 organic after iron washing in the process of treating nickel-cobalt hydroxide materials with a sodium hydroxide solution with a concentration of 1-1.2 mol / L at a phase ratio of O / A = 1:1-1.2, and after mixing for 5 minutes, let it stand and clarify to obtain the saponified organic and the saponification back-extraction liquid, and the saponification back-extraction liquid is in a solid-liquid mixed state; Step 2: Acidify the saponified organic obtained in Step 1 until the organic saponification rate drops to the required production index value of 65%, and then return it to the original production system; Step 3: Heat the saponification back-extraction liquid obtained in Step 1 to 95 °C, and then slowly add an acetic acid solution. Both the scandium hydroxide (Sc(OH)3) dissolved in the saponification back-extraction liquid and hydrolyzed into a solid colloid react with acetic acid to form a scandium acetate precipitate; after precipitation, solid-liquid separation is carried out to obtain a scandium-rich residue and a liquid after scandium precipitation; Step 4: Add caustic soda flakes to the solution after scandium precipitation obtained in Step 3 until the sodium hydroxide concentration reaches 1 - 1.2 mol / L, and then return it for saponifying P204 organic. During the saponification process, sodium acetate remaining in the solution after scandium precipitation will react with the back-extracted scandium to form scandium acetate precipitate, thus achieving no wastewater generation in the entire scandium recovery process.

[0009] Preferably, the addition amount of acetic acid solution in Step 3 is 1.0 - 1.2 times the theoretical amount, and the excess acetic acid reacts with the base to form sodium acetate.

[0010] The beneficial effects of the present invention are as follows: 1. The characteristic of the present invention is to change the saponification method of the original process, separate the saponification back-extraction solution and precipitate scandium. The scandium precipitation reagent has no influence on the original production system. After adding sodium hydroxide to the solution after scandium precipitation, it is returned to the system for reuse. There is no generation of three wastes during the scandium recovery process, which is a clean scandium recovery process method. Using acetic acid to precipitate and recover scandium in the back-extraction solution to obtain scandium-rich slag, there is no wastewater and waste residue production in the whole process, and it has no influence on the original production system, which is a green scandium recovery process method.

[0011] 2. This method uses a sodium hydroxide solution with a certain concentration for saponifying P204 organic and back-extracting scandium after iron washing, obtaining a saponification back-extraction solution containing scandium and scandium hydrolysis products.

[0012] 3. This method uses acetic acid to neutralize and treat the saponification back-extraction solution, converting all scandium into scandium acetate slag with good liquid-solid separation performance. Using acetic acid to precipitate scandium, both Sc(OH)3 dissolved in the saponification back-extraction solution and hydrolyzed into a solid colloid will react with acetic acid to form scandium acetate precipitate.

[0013] 4. This method uses acetic acid to neutralize and precipitate the saponification back-extraction solution. Only acetate ions are introduced in the whole process. The excess acetate ions will form scandium acetate precipitate with scandium. Therefore, no wastewater is generated during the scandium recovery process. After adding caustic soda flakes to the solution after scandium precipitation, it is returned to the saponification back-extraction scandium process for recycling. Description of the Drawings

[0014] Figure 1 It is a process flow diagram of the present invention and its relationship with the original production process. Detailed Embodiments

[0015] The present invention will be further described below in combination with specific embodiments and process flow diagrams: The following non-limiting examples are used to further illustrate the process of the present invention to help understand the present invention and its advantages, and are not used to limit the protection scope of the present invention. The protection scope of the present invention is determined by the claims.

[0016] As Figure 1A method for separating and recovering scandium from P204 organic containing impurities in scandium-containing nickel-cobalt materials. The nickel-cobalt materials involved in this method are nickel-cobalt hydroxide produced by the sulfuric acid leaching process of laterite nickel ore, and its typical components are (%): Ni 38-42, Co 5.0-5.5, Mn 5.0-5.5, Mg 1.0-1.5, Fe 0.1-0.2, Al 0.8-1.2, Sc 0.08-1.0; the organic material for recovering scandium involved is the P204 loaded organic during the purification and impurity removal of the solution after leaching the nickel-cobalt hydroxide material. The present invention uses a sodium hydroxide solution with a certain concentration to back-extract the scandium on the loaded and regenerated P204 organic, and precipitates the back-extract solution to obtain a scandium-rich slag. The sodium hydroxide solution is recycled, realizing a process method for synchronously recovering scandium during the treatment of nickel-cobalt hydroxide materials produced from laterite ore.

[0017] Example 1 Specific implementation process: Step 1: Measure 500 ml of P204 organic after iron washing during the treatment of nickel-cobalt hydroxide material, and prepare 500 ml of sodium hydroxide solution with a concentration of 1 mol / L (O / A = 1:1); shake and mix the two materials for 5 minutes, then let it stand for phase separation. The lower solid-liquid mixture is the saponification back-extract solution, and the upper layer is the saponified organic phase; Step 2: Measure 10 ml of concentrated sulfuric acid, add it to 60 ml of pure water for dilution, and mix the diluted solution with the saponified organic obtained in Step 1 to acidify the organic, so that the saponification rate of the organic drops to about 65% of the production index requirement value, and then return it to the original production system; Step 3: Place the saponification back-extract solution obtained in Step 1 in a stirring reactor, heat it to 95 °C, then start stirring, slowly add 0.25 g of 98.8% acetic acid solution (1.0 times the theoretical amount), after reacting for 20 minutes, perform solid-liquid separation to obtain 1.89 g of scandium-rich slag and the solution after scandium precipitation; Step 4: Place the solution after scandium precipitation obtained in Step 3 in a stirring reactor, start stirring and slowly add 20 g of flake caustic soda, and return it to be used for saponifying P204 organic after it is fully dissolved; 。

[0018] Example 2 Specific implementation process: Step 1: Measure 1000 ml of P204 organic after iron washing during the treatment of nickel-cobalt hydroxide material, and prepare 1200 ml of sodium hydroxide solution with a concentration of 1.2 mol / L (O / A = 1:1.2); shake and mix the two materials for 5 minutes, then let it stand for phase separation. The lower solid-liquid mixture is the saponification back-extract solution, and the upper layer is the saponified organic phase; Step 2: Measure 24 ml of concentrated sulfuric acid and add it to 145 ml of pure water for dilution. The diluted solution is mixed with the saponified organic matter obtained in Step 1, and the organic matter is acidified to reduce the organic saponification rate to about 65% of the production index requirement value, and then returned to the original production system; Step 3: Place the saponified stripping solution obtained in Step 1 in a stirring reactor, heat it to 95 °C, then start stirring, and slowly add 8 g of 98.8% acetic acid solution (1.2 times the theoretical amount). After reacting for 20 minutes, perform solid-liquid separation to obtain 22.10 g of scandium-rich slag and the solution after scandium precipitation; Step 4: Place the solution after scandium precipitation obtained in Step 3 in a stirring reactor, start stirring and slowly add 55 g of flake caustic soda. After it is fully dissolved, it is returned for saponifying P204 organic; 。

Claims

1. A method for separating and recovering scandium from P204 organic impurities in a scandium-nickel-cobalt material, characterized in that The steps include: Step 1: mixing the iron-washed P204 organic in the nickel-cobalt hydroxide material treatment process with a sodium hydroxide solution having a concentration of 1-1.2 mol / L according to a ratio of O / A=1:1-1.2, and standing to clarify after mixing for 5 minutes to obtain a soap organic and a saponification stripping solution, wherein the saponification stripping solution is in a solid-liquid mixed state; Step 2: acidifying the saponified organic matter obtained in step 1, reducing the organic saponification rate to the production index requirement value of 65%, and then returning it to the original production system; Step 3: After heating the saponification stripping solution obtained in step 1 to 95° C., slowly add acetic acid solution, and the Sc(OH)3 dissolved in the saponification stripping solution and hydrolyzed to form a solid colloidal state reacts with acetic acid to generate scandium acetate precipitate; after precipitation, the solid and liquid are separated to obtain scandium-rich slag and a post-scandium precipitation liquid; Step 4: Add caustic soda to the scandium precipitation solution obtained in step 3 until the sodium hydroxide concentration reaches 1-1.2 mol / L, and return to the organic P204 for saponification. The sodium acetate remaining in the scandium precipitation solution will react with the scandium stripped off to form scandium acetate precipitate during the saponification process, thereby achieving the whole scandium recovery process without wastewater generation.

2. The method for separating and recovering scandium from P204 organic impurities in a scandium-nickel-cobalt material according to claim 1, characterized in that: The amount of acetic acid solution added in step 3 is 1.0 to 1.2 times the theoretical amount, and the excess acetic acid reacts with the base to generate sodium acetate.

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