Method for synergistically and deeply purifying rare earth lanthanum and cerium in waste polishing powder pickle liquor
Through the steps of complex salt precipitation, alkalization, acidolysis, extraction and calcination, combined with rare earth synergistic extraction agent, the separation and purification of rare earth elements in waste polishing powder is solved, and efficient and low-cost rare earth elements are achieved.
Patent Information
- Application Number
- CN202510654931.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-05-21
- Publication Date
- 2025-08-08
AI Technical Summary
In the prior art, the separation and purification methods of rare earth elements in waste polishing powder have problems such as poor reaction selectivity, unsatisfactory separation effect, complex operation and high cost, making it difficult to achieve high efficiency and high selectivity rare earth elements recovery.
By using steps such as compound salt precipitation treatment, alkalization reaction, acidolysis reaction, extraction reaction, backextraction reaction, oxalic acid precipitation and calcination, combined with a mixture of rare earth synergistic extraction agents N235, C272 and kerosene, the rare earth sulfate complex salt precipitation, hydroxide precipitation, acidolysis, extraction and backextraction, and finally calcination is used to obtain high-purity rare earth oxides.
The efficient separation and purification of rare earth lanthanum and cerium were achieved, with the extraction rate reaching 99.93% and 99.98%, the separation factor β reached 4557.03, and the purity of rare earth oxides reached 99.99%, which simplified the operation process and reduced costs.
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Figure CN120442966A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the technical field of deep purification and recovery of valuable components in solid waste, in particular to a method for collaborative deep purification of rare earth lanthanum and cerium in waste polishing powder acid leaching solution. Background Art
[0002] With the continuous growth of global demand for rare earth resources, rare earth resources contained in waste have gradually become an important source of recycling. Waste polishing powder, as an industrial waste containing rare earth elements, has received widespread attention in the field of rare earth recycling. At present, among the methods for recycling waste polishing powder at home and abroad, the acid leaching method has the advantages of relatively mild experimental conditions and good economic benefits compared with other methods for recovering rare earths from waste polishing powder. It is widely used in large-scale secondary recycling of rare earth resources. The acid leaching process of rare earth elements in common waste polishing powder is usually accompanied by a large amount of impurity ions. The presence of these impurity ions poses a challenge to the separation and purification of rare earth elements. Therefore, how to achieve high efficiency and high selectivity in the extraction of rare earth elements from waste polishing powder and purification has become a key research issue.
[0003] Traditional rare earth purification methods, such as ion exchange and precipitation, often suffer from poor reaction selectivity, unsatisfactory separation results, and complex operations. A patent discloses a solvent extraction process for recovering rare earth-containing waste. This process uses a traditional P507 extractant and a novel P227 extractant to form a mixed organic phase, followed by a resin phase for saponification-free extraction. Another patent discloses a rare earth extraction and separation method that uses the P507 extractant after saponification and then extracts and separates rare earth lanthanum and cerium from a rare earth chloride solution. These methods are not only complex and require high chemical reagent consumption, but also require specialized process equipment, resulting in high water and energy consumption and high recovery costs.
[0004] Therefore, how to provide a method for the coordinated deep purification of rare earth lanthanum and cerium in the acid leaching solution of waste polishing powder, which is simple to operate and can achieve the technical effect of high rare earth element recovery efficiency and good selectivity, is a technical problem that technical personnel in this field urgently need to solve. Summary of the Invention
[0005] In view of the problems existing in the prior art, the technical problem to be solved by the present invention is to provide a method for the coordinated deep purification of rare earth lanthanum and cerium in the acid leaching solution of waste polishing powder, which is simple to operate and can achieve the technical effect of high rare earth element recovery efficiency and good selectivity. It is a technical problem that technical personnel in this field urgently need to solve.
[0006] To achieve the above-mentioned purpose, the present invention provides a method for the coordinated deep purification of rare earth lanthanum and cerium in waste polishing powder acid leaching liquid, and the method for the coordinated deep purification of rare earth lanthanum and cerium in waste polishing powder acid leaching liquid comprises: double salt precipitation treatment: mixing the waste polishing powder acid leaching liquid with sodium sulfate, carrying out double salt precipitation reaction under heating and stirring conditions, and separating the solid and liquid after the reaction to obtain double salt precipitation residue and double salt precipitation liquid; alkalization reaction: adding sodium hydroxide aqueous solution to the obtained double salt precipitation residue for alkalization reaction, and separating the solid and liquid after the reaction to obtain alkalized liquid and alkalized residue; acidolysis reaction: adding dilute hydrochloric acid to the obtained alkalized residue for acidolysis reaction to obtain acidolysis liquid; extraction: adjusting the pH of the obtained acidolysis liquid with ammonia water, and then mixing with a rare earth synergistic extractant. The steps of: mixing, shaking, and separating the liquids to obtain a first extraction phase and a first raffinate phase; back extraction: adding a sulfuric acid aqueous solution to the obtained first extraction phase, shaking, and separating the liquids to obtain a second extraction phase and a high-purity rare earth solution; oxalic acid precipitation: adding an oxalic acid aqueous solution to the obtained high-purity rare earth solution, and performing oxalic acid precipitation under heating and stirring conditions. After the reaction is completed, solid-liquid separation is performed to obtain oxalic acid precipitation residue and oxalic acid precipitation liquid; calcination: calcining the obtained oxalic acid precipitation residue in a muffle furnace to obtain rare earth oxides; the rare earth synergistic extractant is a mixture of extractant N235, extractant C272, and kerosene; the volume proportions of the extractant N235 and the extractant C272 in the rare earth synergistic extractant are 20-30% and 20-40%, respectively.
[0007] In the first aspect, the solid-liquid ratio of the sodium sulfate to the waste polishing powder acid leaching solution is 100 g / L to 200 g / L; the temperature of the double salt precipitation reaction is 60° C. to 100° C.; and the time of the double salt precipitation reaction is 10 min to 90 min.
[0008] In the first aspect, the sodium hydroxide aqueous solution added in the alkalization reaction is excessive, and the mass concentration of the sodium hydroxide aqueous solution is 30% to 50%.
[0009] In the first aspect, the dilute hydrochloric acid added in the acidolysis reaction is excessive, and the molar concentration of the dilute hydrochloric acid is 0.1 mol / L to 1.0 mol / L.
[0010] In the first aspect, in the extraction step, the pH value of the acid hydrolyzate is adjusted to 1.6-2.0 by the ammonia water; and the volume ratio of the acid hydrolyzate to the rare earth synergistic extractant is 3:1-1:3.
[0011] In the first aspect, in the extraction step, the rotation speed of the oscillation is 50 rpm to 300 rpm, and the oscillation time is 5 min to 20 min.
[0012] In the first aspect, in the stripping step, the volume ratio of the first extraction phase to the aqueous sulfuric acid solution is 3:1 to 1:3; and the molar concentration of the aqueous sulfuric acid solution is 0.2 mol / L to 2 mol / L.
[0013] In the first aspect, in the stripping step, the rotation speed of the oscillation is 50 rpm to 300 rpm, and the oscillation time is 2 min to 15 min.
[0014] In the first aspect, an oxalic acid aqueous solution is added to the obtained high-purity rare earth solution, and oxalic acid precipitation is carried out under heating and stirring conditions. After the reaction is completed, solid-liquid separation is carried out to obtain oxalic acid precipitation residue and oxalic acid precipitation liquid. Specifically, the method includes: adding an oxalic acid aqueous solution with a molar concentration of 1 mol / L to 4 mol / L to the obtained high-purity rare earth solution until the pH of the high-purity rare earth solution is 1.0 to 2, and then stirring at a temperature of 80°C to 100°C and a stirring speed of 300 rpm to 600 rpm for 60 min to 120 min, followed by solid-liquid separation to obtain oxalic acid precipitation residue and oxalic acid precipitation liquid.
[0015] In the first aspect, the calcination temperature is 700° C. to 1000° C., the calcination time is 60 min to 120 min, and the calcination heating rate is 5° C. / min to 20° C. / min.
[0016] Beneficial effects:
[0017] Due to the adoption of the above technical scheme, the present invention has the following advantages compared with the prior art: 1) A method for the coordinated deep purification of rare earth lanthanum and cerium in a waste polishing powder acid leaching solution of the present invention comprises the following steps: adding sodium sulfate to the waste polishing powder acid leaching solution to generate a rare earth sulfate complex salt precipitate, thereby precipitating rare earth elements such as cerium and lanthanum in the waste polishing powder acid leaching solution, and simultaneously generating calcium sulfate and aluminum precipitate, thereby precipitating elements such as aluminum and calcium; then alkalizing the generated rare earth sulfate complex salt precipitate by adding an excess of sodium hydroxide solution to obtain a hydroxide precipitate of rare earth elements such as cerium and lanthanum, and converting the aluminum precipitate into a soluble aluminum-containing compound by adding sodium hydroxide solution, converting the calcium sulfate into calcium hydroxide slightly soluble in water, and separating aluminum and part of the calcium element from rare earth elements such as cerium and lanthanum; then dissolving the hydroxide precipitate of rare earth elements such as cerium and lanthanum and part of the calcium hydroxide by adding a dilute hydrochloric acid solution to obtain an acidolysis solution, wherein the acidolysis solution contains rare earth elements such as cerium and lanthanum, as well as calcium ions and chloride ions; it can be considered that the non-rare earth elements contained in the acidolysis solution are The impurity elements are significantly reduced; a rare earth synergistic extractant is used for extraction to separate the cerium and lanthanum rare earth elements from the impurity elements in the acid solution to obtain a first extraction phase containing cerium and lanthanum rare earth elements. The extraction rate of cerium in the first extraction phase reaches 99.93%, the extraction rate of lanthanum reaches 99.98%, and the separation factor β between cerium, lanthanum and impurity elements reaches 4557.03. It can be considered that the method for the synergistic deep purification of rare earth lanthanum and cerium in the waste polishing powder acid leachate of the present invention combines double salt precipitation technology with extraction, effectively improving the recovery and purification efficiency of rare earth elements in the waste polishing powder acid leachate; sulfuric acid aqueous solution is added to the first extraction phase for stripping to transfer the cerium and lanthanum rare earth elements from the organic phase back to the aqueous phase, and the cerium and lanthanum rare earth elements are further purified to obtain a high-purity rare earth solution; the high-purity rare earth solution is precipitated with oxalic acid to obtain an oxalic acid precipitation residue containing cerium oxalate and lanthanum oxalate, and the oxalic acid precipitation residue is calcined to obtain rare earth oxides containing cerium and lanthanum. The purity of the obtained rare earth oxides reaches 99.99%; It can be seen that the method for the coordinated deep purification of rare earth lanthanum and cerium in the waste polishing powder acid leaching solution of the present invention combines the double salt precipitation technology with extraction and back extraction, which not only effectively improves the recovery efficiency of rare earth elements in the waste polishing powder acid leaching solution, but also ensures the selective deep purification of rare earth elements; 2) The method for the coordinated deep purification of rare earth lanthanum and cerium in the waste polishing powder acid leaching solution of the present invention adopts a rare earth synergistic extractant which is a mixture of extractant N235, extractant C272 and kerosene, and the volume proportions of the extractant N235 and the extractant C272 in the rare earth synergistic extractant are 20-30% and 20-4% respectively. 0%. During the extraction process, the extractants N235 and C272 in the rare earth synergistic extractant have a synergistic effect, improving the extraction selectivity of cerium and lanthanum during the extraction process, and significantly improving the separation of cerium and lanthanum from other elements other than cerium and lanthanum in the complex waste polishing powder acid leaching solution. 3) The present invention provides a method for the synergistic deep purification of rare earth lanthanum and cerium in waste polishing powder acid leaching solution. The pH value during extraction is 1.6-2.0, and the extraction pH is low. Good extraction effect is achieved under low pH conditions, without the need for a complex saponification process, and has the advantages of short phase separation time and simple operation. BRIEF DESCRIPTION OF THE DRAWINGS
[0018] In order to more clearly illustrate the embodiments of this specification or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.
[0019] Figure 1 The present invention is a simplified process flow diagram of a method for collaborative deep purification of rare earth lanthanum and cerium in a waste polishing powder acid leaching solution. DETAILED DESCRIPTION
[0020] The following will be combined with the drawings in the embodiments of this specification to clearly and completely describe the technical solutions in the embodiments of this specification. Obviously, the embodiments described are only part of the embodiments of this specification, not all of the embodiments. Based on the embodiments in this specification, all other embodiments obtained by ordinary technicians in this field are within the scope of protection of this invention.
[0021] Example 1
[0022] like Figure 1As shown, the present embodiment provides a method for the coordinated deep purification of rare earth lanthanum and cerium in the waste polishing powder acid leachate, and the method for the coordinated deep purification of rare earth lanthanum and cerium in the waste polishing powder acid leachate includes: double salt precipitation treatment: mixing the waste polishing powder acid leachate with sodium sulfate, performing a double salt precipitation reaction under heating and stirring conditions, and separating the solid and liquid after the reaction to obtain a double salt precipitation residue and a double salt precipitation liquid; alkalization reaction: adding sodium hydroxide aqueous solution to the obtained double salt precipitation residue for alkalization reaction, and separating the solid and liquid after the reaction to obtain an alkalized liquid and an alkalized residue; acidolysis reaction: adding dilute hydrochloric acid to the obtained alkalized residue for acidolysis reaction to obtain an acidolysis liquid; extraction: adjusting the pH of the obtained acidolysis liquid with ammonia water, and then mixing it with a rare earth synergistic extractant. , shaking and then separating the liquid to obtain a first extraction phase and a first raffinate phase; back extraction: adding a sulfuric acid aqueous solution to the obtained first extraction phase, shaking and then separating the liquid to obtain a second extraction phase and a high-purity rare earth solution; oxalic acid precipitation: adding an oxalic acid aqueous solution to the obtained high-purity rare earth solution, carrying out oxalic acid precipitation under heating and stirring conditions, and after the reaction, solid-liquid separation to obtain oxalic acid precipitation residue and oxalic acid precipitation liquid; calcination: calcining the obtained oxalic acid precipitation residue in a muffle furnace to obtain rare earth oxides; the rare earth synergistic extractant is a mixture of extractant N235, extractant C272 and kerosene; the volume proportions of the extractant N235 and the extractant C272 in the rare earth synergistic extractant are 20-30% and 20%-40%, respectively.
[0023] Compared with the prior art, the method for the coordinated deep purification of rare earth lanthanum and cerium in the acid leaching solution of waste polishing powder provided in Example 1 of the present invention has the following advantages:
[0024] 1. The present invention relates to a method for the coordinated deep purification of rare earth lanthanum and cerium in a waste polishing powder acid leaching solution. The method comprises the following steps: adding sodium sulfate to the waste polishing powder acid leaching solution to generate a rare earth sulfate double salt precipitate, thereby precipitating rare earth elements such as cerium and lanthanum in the waste polishing powder acid leaching solution; and simultaneously generating calcium sulfate and aluminum precipitate, thereby precipitating elements such as aluminum and calcium; then alkalizing the generated rare earth sulfate double salt precipitate by adding an excess of sodium hydroxide solution to obtain a hydroxide precipitate of rare earth elements such as cerium and lanthanum; and converting the aluminum precipitate into a soluble aluminum-containing compound by adding sodium hydroxide solution, thereby purifying the rare earth sulfate double salt precipitate. Calcium is converted into calcium hydroxide which is slightly soluble in water, so that aluminum and part of calcium are separated from rare earth elements such as cerium and lanthanum; then, a dilute hydrochloric acid solution is added to dissolve the hydroxide precipitates of rare earth elements such as cerium and lanthanum and part of calcium hydroxide to obtain an acid hydrolysis solution, which contains rare earth elements such as cerium and lanthanum, as well as calcium ions and chloride ions; it can be considered that the impurity elements other than rare earth elements contained in the acid hydrolysis solution are significantly reduced; a rare earth synergistic extractant is used for extraction to separate the cerium and lanthanum rare earth elements from the impurity elements in the acid hydrolysis solution to obtain a first extraction phase containing cerium and lanthanum rare earth elements, and in the second extraction phase, a precipitate of cerium and lanthanum rare earth elements is dissolved in the second extraction phase. The extraction rate of cerium in the first extraction phase reached 99.93%, the extraction rate of lanthanum reached 99.98%, and the separation factor β between cerium, lanthanum rare earth elements and impurity elements reached 4557.03. It can be considered that the method for the coordinated deep purification of rare earth lanthanum and cerium in the waste polishing powder acid leaching solution of the present invention combines the double salt precipitation technology with extraction, effectively improving the recovery and purification efficiency of rare earth elements in the waste polishing powder acid leaching solution; sulfuric acid aqueous solution is added to the first extraction phase for stripping, and the cerium and lanthanum rare earth elements are transferred from the organic phase back to the aqueous phase, and the cerium and lanthanum rare earth elements are further separated. The earth elements are purified to obtain a high-purity rare earth solution; the high-purity rare earth solution is precipitated with oxalic acid to obtain oxalic acid precipitation residue containing cerium oxalate and lanthanum oxalate; the oxalic acid precipitation residue is calcined to obtain rare earth oxides containing cerium and lanthanum, and the purity of the obtained rare earth oxides reaches 99.99%; it can be seen that the method for the coordinated deep purification of rare earth lanthanum and cerium in the waste polishing powder acid leaching solution of the present invention combines the double salt precipitation technology with extraction and back extraction, which not only effectively improves the recovery efficiency of rare earth elements in the waste polishing powder acid leaching solution, but also ensures the selective deep purification of rare earth elements.
[0025] 2. The present invention provides a method for the synergistic deep purification of rare earth lanthanum and cerium in a waste polishing powder acid leachate. The rare earth synergistic extractant used is a mixture of extractant N235, extractant C272 and kerosene, and the volume proportions of the extractant N235 and extractant C272 in the rare earth synergistic extractant are 20-30% and 20-40%, respectively. During the extraction process, the extractant N235 and extractant C272 in the rare earth synergistic extractant have a synergistic effect, which improves the extraction selectivity of cerium and lanthanum during the extraction process, and significantly improves the separation effect of cerium and lanthanum from other elements other than cerium and lanthanum in a complex waste polishing powder acid leachate.
[0026] 3. The method of the present invention for the coordinated deep purification of rare earth lanthanum and cerium in the acid leaching solution of waste polishing powder has a pH value of 1.6 to 2.0 during extraction, a low extraction pH value, and a good extraction effect under low pH conditions. It does not require a complex saponification process and has the advantages of short phase separation time and simple operation.
[0027] In some possible implementations, the solid-liquid ratio of the sodium sulfate to the waste polishing powder acid leaching solution is 100 g / L to 200 g / L; the temperature of the double salt precipitation reaction is 60° C. to 100° C.; and the time of the double salt precipitation reaction is 10 min to 90 min.
[0028] Specifically, the waste polishing powder acid leaching solution contains elements such as cerium, lanthanum, aluminum, and calcium. By adding sodium sulfate to the waste polishing powder acid leaching solution for complex salt precipitation, it is mainly used to precipitate rare earth elements such as cerium and lanthanum.
[0029] In some possible implementations, the sodium hydroxide aqueous solution added in the alkalization reaction is excessive, and the mass concentration of the sodium hydroxide aqueous solution is 30% to 50%.
[0030] Specifically, the excess sodium hydroxide aqueous solution is mainly used to convert the non-rare earth elements in the double salt precipitation residue into soluble compounds, so as to separate the non-rare earth elements from rare earth elements such as cerium and lanthanum.
[0031] In some possible implementations, the dilute hydrochloric acid added in the acidolysis reaction is excessive, and the molar concentration of the dilute hydrochloric acid is 0.1 mol / L to 1.0 mol / L.
[0032] Specifically, excess dilute hydrochloric acid is mainly used to dissolve the hydroxide precipitates of rare earth elements such as cerium and lanthanum, so as to facilitate subsequent extraction.
[0033] In some possible implementations, in the extraction step, the pH value of the acid hydrolyzate is adjusted to 1.6 to 2.0 by the ammonia water; the volume ratio of the acid hydrolyzate to the rare earth synergistic extractant is 3:1 to 1:3; in the extraction step, the oscillation speed is 50 rpm to 300 rpm, and the oscillation time is 5 min to 20 min.
[0034] Specifically, the pH value of the acid hydrolyzate is adjusted to 1.6-2.0 by using ammonia water to improve the extraction effect and reduce the extraction phase separation time.
[0035] In some possible implementations, in the stripping step, the volume ratio of the first extraction phase to the aqueous sulfuric acid solution is 3:1 to 1:3; the molar concentration of the aqueous sulfuric acid solution is 0.2 mol / L to 2 mol / L; in the stripping step, the oscillation speed is 50 rpm to 300 rpm, and the oscillation time is 2 min to 15 min.
[0036] Specifically, aqueous sulfuric acid solution is used as a stripping agent, mainly used to convert the cerium and lanthanum rare earth elements in the first extraction phase from the organic phase to the aqueous phase, and further purify the cerium and lanthanum rare earth elements.
[0037] In some possible implementations, an oxalic acid aqueous solution is added to the obtained high-purity rare earth solution, oxalic acid precipitation is carried out under heating and stirring conditions, and after the reaction is completed, solid-liquid separation is carried out to obtain oxalic acid precipitate residue and oxalic acid precipitate liquid. Specifically, the process includes: adding an oxalic acid aqueous solution with a molar concentration of 1 mol / L to 4 mol / L to the obtained high-purity rare earth solution until the pH of the high-purity rare earth solution is 1.0 to 2, then stirring at a temperature of 80°C to 100°C and a stirring speed of 300 rpm to 600 rpm for 60 min to 120 min, followed by solid-liquid separation to obtain oxalic acid precipitate residue and oxalic acid precipitate liquid; the calcination temperature is 700°C to 1000°C, the calcination time is 60 min to 120 min, and the calcination heating rate is 5°C / min to 20°C / min.
[0038] Specifically, by adding an aqueous oxalic acid solution to a high-purity rare earth solution to a pH of 1.0 to 2, an oxalic acid precipitation reaction is carried out within this pH range, so that the cerium element and lanthanum element in the high-purity rare earth solution are converted into cerium oxalate and lanthanum oxalate, which are then calcined at high temperature to obtain rare earth oxides containing cerium oxide and lanthanum oxide. The cerium and lanthanum rare earth elements are extracted and purified together and then commercialized, thereby realizing the recycling of material resources and having economic benefits.
[0039] In order to further illustrate the technical solution of the present application in detail to support the technical problem to be solved by the present application, a method for the coordinated deep purification of rare earth lanthanum and cerium in an acid leaching solution of waste polishing powder is specifically illustrated below, as shown in Examples 1 to 4 and Comparative Examples 1 to 2.
[0040] Example 1
[0041] A method for the coordinated deep purification of rare earth lanthanum and cerium in a waste polishing powder acid leaching solution, specifically comprising:
[0042] Double salt precipitation treatment: the waste polishing powder acid leaching solution is mixed with sodium sulfate, and the mixture is reacted at 95°C under stirring and heating conditions for 30 minutes. After the reaction, the solid and liquid are separated to obtain double salt precipitate residue and double salt precipitate; the solid-liquid ratio of the sodium sulfate to the waste polishing powder acid leaching solution is 200g / L;
[0043] Alkalization reaction: adding an excess amount of 50% sodium hydroxide aqueous solution to the obtained double salt precipitate residue to carry out an alkalization reaction, and after the reaction is completed, separating the solid and the liquid to obtain an alkalized liquid and an alkalized residue;
[0044] Acid hydrolysis reaction: adding an excess amount of dilute hydrochloric acid with a molar concentration of 0.5 mol / L to the obtained alkalized slag to carry out acid hydrolysis reaction to obtain an acid hydrolysis solution;
[0045] Extraction: The obtained acid hydrolyzate was adjusted to a pH of 1.8 with aqueous ammonia, then mixed with a rare earth synergistic extractant, and shaken at a shaking speed of 200 rpm for 10 minutes before separation to obtain a first extract phase and a first raffinate phase; the volume ratio of the acid hydrolyzate to the rare earth synergistic extractant was 1:1; the rare earth synergistic extractant was a mixture of extractant N235, extractant C272, and kerosene, wherein the volume of the rare earth synergistic extractant was 25% by volume of the extractant N235, 35% by volume of the extractant C272, and 40% by volume of the kerosene;
[0046] Stripping: adding a 1.2 mol / L sulfuric acid aqueous solution to the obtained first extract phase, shaking at a shaking speed of 200 rpm for 10 minutes, and then separating the liquids to obtain a second extract phase and a high-purity rare earth solution; the volume ratio of the first extract phase to the sulfuric acid aqueous solution is 1:1;
[0047] Oxalic acid precipitation: adding an aqueous oxalic acid solution with a molar concentration of 2 mol / L to the obtained high-purity rare earth solution until the pH of the high-purity rare earth solution reaches 1.5, then stirring at 85° C. and 400 rpm for 60 minutes, followed by solid-liquid separation to obtain oxalic acid precipitate residue and oxalic acid precipitate liquid;
[0048] Calcination: The obtained oxalic acid precipitated slag was placed in a muffle furnace, heated to 900°C at a heating rate of 10°C / min, and maintained at 900°C for 60 minutes to obtain rare earth oxides.
[0049] Example 2
[0050] A method for the coordinated deep purification of rare earth lanthanum and cerium in a waste polishing powder acid leaching solution, specifically comprising:
[0051] Double salt precipitation treatment: the waste polishing powder acid leaching solution is mixed with sodium sulfate, and the mixture is reacted at 95°C under stirring and heating conditions for 30 minutes. After the reaction, the solid and liquid are separated to obtain double salt precipitate residue and double salt precipitate; the solid-liquid ratio of the sodium sulfate to the waste polishing powder acid leaching solution is 200g / L;
[0052] Alkalization reaction: adding an excess amount of 50% sodium hydroxide aqueous solution to the obtained double salt precipitate residue to carry out an alkalization reaction, and after the reaction is completed, separating the solid and the liquid to obtain an alkalized liquid and an alkalized residue;
[0053] Acid hydrolysis reaction: adding an excess amount of dilute hydrochloric acid with a molar concentration of 0.5 mol / L to the obtained alkalized slag to carry out acid hydrolysis reaction to obtain an acid hydrolysis solution;
[0054] Extraction: The obtained acid hydrolyzate was adjusted to a pH of 1.8 with aqueous ammonia, then mixed with a rare earth synergistic extractant, and shaken at a shaking speed of 200 rpm for 8 minutes, followed by liquid separation to obtain a first extract phase and a first raffinate phase; the volume ratio of the acid hydrolyzate to the rare earth synergistic extractant was 1:1.2; the rare earth synergistic extractant was a mixture of extractant N235, extractant C272, and kerosene, wherein the volume of the rare earth synergistic extractant was 25% by volume of the extractant N235, 35% by volume of the extractant C272, and 40% by volume of the kerosene;
[0055] Stripping: adding a 1.2 mol / L sulfuric acid aqueous solution to the obtained first extract phase, shaking at a shaking speed of 200 rpm for 10 minutes, and then separating the liquids to obtain a second extract phase and a high-purity rare earth solution; the volume ratio of the first extract phase to the sulfuric acid aqueous solution is 1:1;
[0056] Oxalic acid precipitation: adding an aqueous oxalic acid solution with a molar concentration of 2 mol / L to the obtained high-purity rare earth solution until the pH of the high-purity rare earth solution reaches 1.5, then stirring at 85° C. and 400 rpm for 60 minutes, followed by solid-liquid separation to obtain oxalic acid precipitate residue and oxalic acid precipitate liquid;
[0057] Calcination: The obtained oxalic acid precipitated slag was placed in a muffle furnace, heated to 900°C at a heating rate of 10°C / min, and maintained at 900°C for 60 minutes to obtain rare earth oxides.
[0058] Example 3
[0059] A method for the coordinated deep purification of rare earth lanthanum and cerium in a waste polishing powder acid leaching solution, specifically comprising:
[0060] Double salt precipitation treatment: the waste polishing powder acid leaching solution is mixed with sodium sulfate, and the mixture is reacted at 95°C under stirring and heating conditions for 30 minutes. After the reaction, the solid and liquid are separated to obtain double salt precipitate residue and double salt precipitate; the solid-liquid ratio of the sodium sulfate to the waste polishing powder acid leaching solution is 200g / L;
[0061] Alkalization reaction: adding an excess amount of 50% sodium hydroxide aqueous solution to the obtained double salt precipitate residue to carry out an alkalization reaction, and after the reaction is completed, separating the solid and the liquid to obtain an alkalized liquid and an alkalized residue;
[0062] Acid hydrolysis reaction: adding an excess amount of dilute hydrochloric acid with a molar concentration of 0.5 mol / L to the obtained alkalized slag to carry out acid hydrolysis reaction to obtain an acid hydrolysis solution;
[0063] Extraction: The obtained acid hydrolyzate was adjusted to a pH of 1.8 with aqueous ammonia, then mixed with a rare earth synergistic extractant, and shaken at a shaking speed of 200 rpm for 15 minutes, followed by liquid separation to obtain a first extract phase and a first raffinate phase; the volume ratio of the acid hydrolyzate to the rare earth synergistic extractant was 1:1; the rare earth synergistic extractant was a mixture of extractant N235, extractant C272, and kerosene, wherein the volume of the rare earth synergistic extractant was 25% by volume of the extractant N235, 35% by volume of the extractant C272, and 40% by volume of the kerosene;
[0064] Stripping: adding a 1.2 mol / L sulfuric acid aqueous solution to the obtained first extract phase, shaking at a shaking speed of 200 rpm for 10 minutes, and then separating the liquids to obtain a second extract phase and a high-purity rare earth solution; the volume ratio of the first extract phase to the sulfuric acid aqueous solution is 1:1;
[0065] Oxalic acid precipitation: adding an aqueous oxalic acid solution with a molar concentration of 2 mol / L to the obtained high-purity rare earth solution until the pH of the high-purity rare earth solution reaches 1.5, then stirring at 85° C. and 400 rpm for 60 minutes, followed by solid-liquid separation to obtain oxalic acid precipitate residue and oxalic acid precipitate liquid;
[0066] Calcination: The obtained oxalic acid precipitated slag was placed in a muffle furnace, heated to 900°C at a heating rate of 10°C / min, and maintained at 900°C for 60 minutes to obtain rare earth oxides.
[0067] Example 4
[0068] A method for the coordinated deep purification of rare earth lanthanum and cerium in a waste polishing powder acid leaching solution, specifically comprising:
[0069] Double salt precipitation treatment: the waste polishing powder acid leaching solution is mixed with sodium sulfate, and the mixture is reacted at 95°C under stirring and heating conditions for 30 minutes. After the reaction, the solid and liquid are separated to obtain double salt precipitate residue and double salt precipitate; the solid-liquid ratio of the sodium sulfate to the waste polishing powder acid leaching solution is 200g / L;
[0070] Alkalization reaction: adding an excess amount of 50% sodium hydroxide aqueous solution to the obtained double salt precipitate residue to carry out an alkalization reaction, and after the reaction is completed, separating the solid and the liquid to obtain an alkalized liquid and an alkalized residue;
[0071] Acid hydrolysis reaction: adding an excess amount of dilute hydrochloric acid with a molar concentration of 0.5 mol / L to the obtained alkalized slag to carry out acid hydrolysis reaction to obtain an acid hydrolysis solution;
[0072] Extraction: The obtained acid hydrolyzate was adjusted to a pH of 1.8 with aqueous ammonia, then mixed with a rare earth synergistic extractant, and shaken at a shaking speed of 200 rpm for 20 minutes, followed by liquid separation to obtain a first extract phase and a first raffinate phase; the volume ratio of the acid hydrolyzate to the rare earth synergistic extractant was 1:1; the rare earth synergistic extractant was a mixture of extractant N235, extractant C272, and kerosene, wherein the volume of the rare earth synergistic extractant was 25% by volume of the extractant N235, 35% by volume of the extractant C272, and 40% by volume of the kerosene;
[0073] Stripping: adding a 1.2 mol / L sulfuric acid aqueous solution to the obtained first extract phase, shaking at a shaking speed of 200 rpm for 10 minutes, and then separating the liquids to obtain a second extract phase and a high-purity rare earth solution; the volume ratio of the first extract phase to the sulfuric acid aqueous solution is 1:1;
[0074] Oxalic acid precipitation: adding an aqueous oxalic acid solution with a molar concentration of 2 mol / L to the obtained high-purity rare earth solution until the pH of the high-purity rare earth solution reaches 1.5, then stirring at 85° C. and 400 rpm for 60 minutes, followed by solid-liquid separation to obtain oxalic acid precipitate residue and oxalic acid precipitate liquid;
[0075] Calcination: The obtained oxalic acid precipitated slag was placed in a muffle furnace, heated to 900°C at a heating rate of 10°C / min, and maintained at 900°C for 60 minutes to obtain rare earth oxides.
[0076] Comparative Example 1
[0077] A method for the coordinated deep purification of rare earth lanthanum and cerium in a waste polishing powder acid leaching solution, specifically comprising:
[0078] Double salt precipitation treatment: the waste polishing powder acid leaching solution is mixed with sodium sulfate, and the mixture is reacted at 95°C under stirring and heating conditions for 30 minutes. After the reaction, the solid and liquid are separated to obtain double salt precipitate residue and double salt precipitate; the solid-liquid ratio of the sodium sulfate to the waste polishing powder acid leaching solution is 200g / L;
[0079] Alkalization reaction: adding an excess amount of 50% sodium hydroxide aqueous solution to the obtained double salt precipitate residue to carry out an alkalization reaction, and after the reaction is completed, separating the solid and the liquid to obtain an alkalized liquid and an alkalized residue;
[0080] Acid hydrolysis reaction: adding an excess amount of dilute hydrochloric acid with a molar concentration of 0.5 mol / L to the obtained alkalized slag to carry out acid hydrolysis reaction to obtain an acid hydrolysis solution;
[0081] Extraction: The obtained acid hydrolyzate was adjusted to a pH of 1.8 with aqueous ammonia, then mixed with a rare earth synergistic extractant, and shaken at a shaking speed of 200 rpm for 10 minutes before separation to obtain a first extract phase and a first raffinate phase; the volume ratio of the acid hydrolyzate to the rare earth synergistic extractant was 1:1; the rare earth synergistic extractant was a mixture of extractant N235 and kerosene, wherein the volume of the rare earth synergistic extractant was 60% by volume of the extractant N235 and 40% by volume of the kerosene;
[0082] Stripping: adding a 1.2 mol / L sulfuric acid aqueous solution to the obtained first extract phase, shaking at a shaking speed of 200 rpm for 10 minutes, and then separating the liquids to obtain a second extract phase and a high-purity rare earth solution; the volume ratio of the first extract phase to the sulfuric acid aqueous solution is 1:1;
[0083] Oxalic acid precipitation: adding an aqueous oxalic acid solution with a molar concentration of 2 mol / L to the obtained high-purity rare earth solution until the pH of the high-purity rare earth solution reaches 1.5, then stirring at 85° C. and 400 rpm for 60 minutes, followed by solid-liquid separation to obtain oxalic acid precipitate residue and oxalic acid precipitate liquid;
[0084] Calcination: The obtained oxalic acid precipitated slag was placed in a muffle furnace, heated to 900°C at a heating rate of 10°C / min, and maintained at 900°C for 60 minutes to obtain rare earth oxides.
[0085] Comparative Example 2
[0086] A method for the coordinated deep purification of rare earth lanthanum and cerium in a waste polishing powder acid leaching solution, specifically comprising:
[0087] Double salt precipitation treatment: the waste polishing powder acid leaching solution is mixed with sodium sulfate, and the mixture is reacted at 95°C under stirring and heating conditions for 30 minutes. After the reaction, the solid and liquid are separated to obtain double salt precipitate residue and double salt precipitate; the solid-liquid ratio of the sodium sulfate to the waste polishing powder acid leaching solution is 200g / L;
[0088] Alkalization reaction: adding an excess amount of 50% sodium hydroxide aqueous solution to the obtained double salt precipitate residue to carry out an alkalization reaction, and after the reaction is completed, separating the solid and the liquid to obtain an alkalized liquid and an alkalized residue;
[0089] Acid hydrolysis reaction: adding an excess amount of dilute hydrochloric acid with a molar concentration of 0.5 mol / L to the obtained alkalized slag to carry out acid hydrolysis reaction to obtain an acid hydrolysis solution;
[0090] Extraction: The obtained acid hydrolyzate was adjusted to a pH of 1.8 with aqueous ammonia, then mixed with a rare earth synergistic extractant, and shaken at a shaking speed of 200 rpm for 10 minutes before separation to obtain a first extract phase and a first raffinate phase; the volume ratio of the acid hydrolyzate to the rare earth synergistic extractant was 1:1; the rare earth synergistic extractant was a mixture of extractant C272 and kerosene, wherein the volume of the extractant C272 accounted for 60% and the volume of the kerosene accounted for 40% of the rare earth synergistic extractant;
[0091] Stripping: adding a 1.2 mol / L sulfuric acid aqueous solution to the obtained first extract phase, shaking at a shaking speed of 200 rpm for 10 minutes, and then separating the liquids to obtain a second extract phase and a high-purity rare earth solution; the volume ratio of the first extract phase to the sulfuric acid aqueous solution is 1:1;
[0092] Oxalic acid precipitation: adding an aqueous oxalic acid solution with a molar concentration of 2 mol / L to the obtained high-purity rare earth solution until the pH of the high-purity rare earth solution reaches 1.5, then stirring at 85° C. and 400 rpm for 60 minutes, followed by solid-liquid separation to obtain oxalic acid precipitate residue and oxalic acid precipitate liquid;
[0093] Calcination: The obtained oxalic acid precipitated slag was placed in a muffle furnace, heated to 900°C at a heating rate of 10°C / min, and maintained at 900°C for 60 minutes to obtain rare earth oxides.
[0094] The extraction rate of cerium element, the extraction rate of lanthanum element, and the separation factor between rare earth elements and impurity elements of the first extraction phase obtained in Examples 1 to 4 and Comparative Examples 1 to 2 were tested. At the same time, the purity of the rare earth oxides obtained in Examples 1 to 4 and Comparative Examples 1 to 2 was tested. The test results are shown in Table 1.
[0095] Table 1 Test results
[0096] Example Cerium extraction rate Lanthanum extraction rate Separation factor β Rare earth oxide purity Example 1 99.93％ 99.98％ 4557.03 99.99％ Example 2 99.91％ 99.86％ 2417.35 99.97％ Example 3 99.84％ 99.58％ 1320.65 99.95％ Example 4 99.81％ 98.98％ 1093.09 99.92％ Comparative Example 1 4.96％ 0.24％ 0.04 71.63％ Comparative Example 2 17.06％ 3.3％ 0.95 97.54％
[0097] As can be seen from Examples 1 to 4 in Table 1, the extraction rate of cerium can reach 99.93%, the extraction rate of lanthanum can reach 99.98%, and the separation factor β between cerium, lanthanum and other elements other than cerium and lanthanum can reach 4557.03, and the purity of rare earth oxides is high, reaching 99.99%. It can be seen that the method for the coordinated deep purification of rare earth lanthanum and cerium in the waste polishing powder acid leaching solution of the present invention has a high extraction rate of cerium and lanthanum in the waste polishing powder acid leaching solution, and can selectively extract cerium and lanthanum together; at the same time, it also ensures the purity of rare earth High purification of oxides; by comparing Example 1 with Comparative Examples 1-2, it can be seen that the extraction rates of cerium and lanthanum in Comparative Examples 1 and 2 do not exceed 20%, and the separation factor β does not exceed 1. Comparative Examples 1 and 2 respectively use only one of the extractants N235 and C272 mixed with kerosene as the extractant for the extraction reaction; it can be considered that among the rare earth synergistic extractants, the extractant N235 and the extractant C272 have a synergistic effect, which can significantly improve the selective co-extraction of cerium and lanthanum.
[0098] The above describes in detail the preferred embodiments of the present invention. It should be understood that those skilled in the art can make numerous modifications and variations based on the concepts of the present invention without inventive effort. Therefore, any technical solutions that can be derived by those skilled in the art through logical analysis, reasoning, or limited experimentation based on the concepts of the present invention and the prior art should be within the scope of protection defined by the claims.
Claims
1. A method for the coordinated deep purification of rare earth lanthanum and cerium in waste polishing powder acid leaching solution, characterized in that: The method for collaborative deep purification of rare earth lanthanum and cerium in the waste polishing powder acid leaching solution comprises: Complex salt precipitation treatment: the waste polishing powder acid leaching solution is mixed with sodium sulfate, and a complex salt precipitation reaction is carried out under heating and stirring conditions. After the reaction is completed, the solid and liquid are separated to obtain complex salt precipitation residue and complex salt precipitation liquid; Alkalization reaction: adding a sodium hydroxide aqueous solution to the obtained double salt precipitate residue to carry out an alkalization reaction, and after the reaction is completed, separating the solid and the liquid to obtain an alkalized liquid and an alkalized residue; Acid hydrolysis reaction: adding dilute hydrochloric acid to the obtained alkalized slag to carry out acid hydrolysis reaction to obtain acid hydrolysis solution; Extraction: The pH of the obtained acid hydrolyzate is adjusted with aqueous ammonia, then mixed with a rare earth synergistic extractant, shaken, and separated to obtain a first extract phase and a first raffinate phase; Stripping: adding aqueous sulfuric acid solution to the obtained first extraction phase, shaking and separating the liquids to obtain the second extraction phase and high-purity rare earth solution; Oxalic acid precipitation: adding an oxalic acid aqueous solution to the obtained high-purity rare earth solution, performing oxalic acid precipitation under heating and stirring conditions, and after the reaction is completed, solid-liquid separation to obtain oxalic acid precipitation residue and oxalic acid precipitation liquid; Calcination: calcining the obtained oxalic acid precipitated residue in a muffle furnace to obtain rare earth oxides; The rare earth synergistic extractant is a mixture of extractant N235, extractant C272 and kerosene; the volume proportions of the extractant N235 and the extractant C272 in the rare earth synergistic extractant are 20-30% and 20-40% respectively.
2. The method for synergistic deep purification of rare earth lanthanum and cerium in a waste polishing powder acid leaching solution according to claim 1, characterized in that: The solid-liquid ratio of the sodium sulfate to the waste polishing powder acid leaching solution is 100 g / L to 200 g / L; the temperature of the double salt precipitation reaction is 60° C. to 100° C.; and the time of the double salt precipitation reaction is 10 min to 90 min.
3. The method for synergistic deep purification of rare earth lanthanum and cerium in a waste polishing powder acid leaching solution according to claim 2, characterized in that: The sodium hydroxide aqueous solution added in the alkalization reaction is excessive, and the mass concentration of the sodium hydroxide aqueous solution is 30% to 50%.
4. The method for synergistic deep purification of rare earth lanthanum and cerium in a waste polishing powder acid leaching solution according to claim 3, characterized in that: The dilute hydrochloric acid added in the acidolysis reaction is excessive, and the molar concentration of the dilute hydrochloric acid is 0.1 mol / L to 1.0 mol / L.
5. The method for synergistic deep purification of rare earth lanthanum and cerium in a waste polishing powder acid leaching solution according to claim 4, characterized in that: In the extraction step, the pH value of the acid hydrolysis solution is adjusted to 1.6-2.0 by the ammonia water; and the volume ratio of the acid hydrolysis solution to the rare earth synergistic extractant is 3:1-1:
3.
6. The method for synergistic deep purification of rare earth lanthanum and cerium in a waste polishing powder acid leaching solution according to claim 5, characterized in that: In the extraction step, the rotation speed of the oscillation is 50 rpm to 300 rpm, and the oscillation time is 5 min to 20 min.
7. The method for synergistic deep purification of rare earth lanthanum and cerium in a waste polishing powder acid leaching solution according to claim 6, characterized in that: In the stripping step, the volume ratio of the first extraction phase to the aqueous sulfuric acid solution is 3:1 to 1:3; and the molar concentration of the aqueous sulfuric acid solution is 0.2 mol / L to 2 mol / L.
8. The method for synergistic deep purification of rare earth lanthanum and cerium in a waste polishing powder acid leaching solution according to claim 7, characterized in that: In the stripping step, the rotation speed of the oscillation is 50 rpm to 300 rpm, and the oscillation time is 2 min to 15 min.
9. The method for synergistic deep purification of rare earth lanthanum and cerium in a waste polishing powder acid leaching solution according to claim 8, characterized in that: The method comprises adding an oxalic acid aqueous solution to the obtained high-purity rare earth solution, performing oxalic acid precipitation under heating and stirring conditions, and performing solid-liquid separation after the reaction to obtain oxalic acid precipitation residue and oxalic acid precipitation liquid. The method specifically comprises: adding an oxalic acid aqueous solution with a molar concentration of 1 mol / L to 4 mol / L to the obtained high-purity rare earth solution until the pH value of the high-purity rare earth solution is 1.0 to 2, then stirring at a temperature of 80° C. to 100° C. and a stirring speed of 300 rpm to 600 rpm for 60 min to 120 min, and then performing solid-liquid separation to obtain oxalic acid precipitation residue and oxalic acid precipitation liquid.
10. The method for synergistic deep purification of rare earth lanthanum and cerium in a waste polishing powder acid leaching solution according to claim 9, characterized in that: The calcination temperature is 700° C. to 1000° C., the calcination time is 60 min to 120 min, and the calcination heating rate is 5° C. / min to 20° C. / min.