阅读说明：本技术 从fcc废催化剂中回收稀土镧和铈的方法 (Method for recovering rare earth lanthanum and cerium from FCC spent catalyst ) 是由 张宏哲 刘政伟 郭磊 房师平 张志远 牟桂芹 于 2019-03-15 设计创作，主要内容包括：本发明涉及一种从FCC废催化剂中回收稀土镧和铈的方法,主要解决现有技术中FCC废催化剂难以环保处理、处理成本高、回收率低的问题。本发明通过采用一种从FCC废催化剂中回收稀土镧和铈的方法,以酸溶液为提取剂,在一定温度和浓度下,利用酸将废催化剂中的稀土元素浸取到溶液中,得到含有稀土的浸出液,浸出液经除铝、硅后得到净化稀土溶液,然后经萃取、反萃取得到纯净稀土溶液的技术方案较好地解决了上述问题,可用于从FCC废催化剂中回收稀土镧和铈中。(The invention relates to a method for recovering rare earth lanthanum and cerium from FCC spent catalyst, which mainly solves the problems that the FCC spent catalyst in the prior art is difficult to be processed in an environment-friendly way, has high processing cost and low recovery rate. The invention better solves the problems by adopting the technical scheme that the method for recovering rare earth lanthanum and cerium from FCC spent catalyst uses acid solution as an extracting agent, rare earth elements in the spent catalyst are leached into the solution by acid at certain temperature and concentration to obtain leachate containing rare earth, the leachate is subjected to aluminum and silicon removal to obtain purified rare earth solution, and then the purified rare earth solution is obtained through extraction and back extraction.)

1. A method for recovering rare earth lanthanum and cerium from FCC spent catalyst comprises using acid solution as extractant, leaching rare earth elements in the spent catalyst into the solution by using acid at a certain temperature and concentration to obtain leachate containing rare earth, removing aluminum and silicon from the leachate to obtain purified rare earth solution, and then extracting and back-extracting to obtain pure rare earth solution.

2. The method for recovering rare earth lanthanum and cerium from spent FCC catalyst as claimed in claim 1, wherein the spent FCC catalyst is a spent balancer directly discharged from a catalytic cracking unit, and has a particle size of 30-150 μm and an average particle size of 60-90 μm.

3. The method for recovering rare earth lanthanum and cerium from FCC spent catalyst according to claim 1, wherein the acid solution is nitric acid, sulfuric acid or hydrochloric acid solution, the concentration of the acid solution is 0.5-8mol/L, and the liquid-solid volume ratio of the acid solution to the spent catalyst is 2-10: 1.

4. The method for recovering rare earth lanthanum and cerium from FCC spent catalyst according to claim 2, wherein the acid solution is nitric acid or hydrochloric acid solution, the concentration of the acid solution is 1-4mol/L, and the liquid-solid volume ratio of the acid solution to the spent catalyst is 5-8: 1.

5. The method of recovering rare earth lanthanum and cerium from spent FCC catalyst as claimed in claim 1, wherein the leaching time is 1-24h, the leaching temperature is 25-95 ℃, and the stirring rate during leaching is 0-500 r/min.

6. The method for recovering rare earth lanthanum and cerium from spent FCC catalyst according to claim 5, wherein the leaching time is 6-10h, the leaching temperature is 50-85 ℃, and the stirring rate during leaching is 80-200 r/min.

7. The method for recovering rare earth lanthanum and cerium from FCC spent catalyst according to claim 1, wherein the leachate is slowly added into NaOH solution while stirring, filtered, drained and dried to obtain a filter cake rich in aluminum-removed rare earth; completely dissolving the filter cake after removing aluminum and drying by hydrochloric acid solution, heating, standing and cooling, and filtering to obtain a rare earth-rich solution after removing silicon; the volume ratio of the leaching solution to the NaOH solution is 2-5: 1.

8. The method of claim 1, wherein the rare earth lanthanum and cerium are recovered from the spent FCC catalyst by selecting a suitable extractant, adjusting the concentration of the extractant, removing silicon, obtaining a rare earth-rich solution pH and phase ratio to obtain a rare earth-rich extract, and back-extracting to obtain a pure rare earth solution; the extraction agent selected in the extraction process is P204 or P507, the volume fraction of the extraction agent is 5-70%, the pH of the rare earth-rich solution after silicon removal is adjusted to be 1-4, and the extraction ratio is 1:2 to 4: 1.

9. The method of claim 8, wherein the extraction agent is P507, the volume fraction of the extraction agent is 50% -70%, the pH of the rare earth-rich solution after silicon removal is adjusted to 2-3, and the extraction ratio is 2-3: 1.

10. The method of claim 9, wherein the extraction agent is P507, the volume fraction of the extraction agent is 55-60%, the pH of the rare earth-rich solution after silicon removal is adjusted to 2-3, and the extraction ratio is 2.5-3: 1.

Technical Field

The invention relates to a method for recovering rare earth lanthanum and cerium from FCC spent catalyst, in particular to a method for extracting rare earth elements of lanthanum and cerium from FCC spent catalyst by utilizing low-temperature acid leaching-impurity removal-extraction process.

Background

In the modern petroleum refining industry, a Fluid Catalytic Cracking (FCC) process plays an important role, and FCC catalysts containing molecular sieves are commonly used, and have the characteristics of high activity, strong selectivity, good stability, good regeneration performance, strong poisoning resistance and the like. In order to further improve the quality of the FCC catalyst, so that the FCC catalyst has higher catalytic activity, better thermal stability and hydrothermal stability and better regeneration performance, the catalyst can be modified by rare earth elements in the preparation process, and the FCC catalyst is rich in rare earth lanthanum and cerium.

The rare earth elements have excellent optical, electric, nuclear, magnetic and other characteristics, are important research and development objects for the exploration of modern high-tech materials, are 'new material treasury' and 'vitamins of modern industry', are considered as indispensable 'technical metals' by countries in the world, and have increasing strategic position in China. The FCC spent catalyst contains 2-5 wt% of lanthanum and cerium rare earth elements (calculated by oxide), which are almost comparable to the content of rare earth ore, and the types of elements in the spent catalyst are less, so the rare earth elements in the FCC spent catalyst have higher recovery value. However, after the rare earth type FCC catalyst is used for a long time, the catalytic activity is reduced due to the impact of high temperature, poison, coking, mechanical abrasion, thermal crumbling and the like, and it is necessary to add part of fresh catalyst and discharge part of spent catalyst to maintain the activity and selectivity of the catalytic cracking unit. However, the FCC waste catalyst discharged from the catalytic cracking unit belongs to dangerous solid waste, and is currently disposed in landfills, occupying a large amount of land resources, and a large amount of recoverable rare earth resources are wasted. Therefore, the rare earth elements in the FCC waste catalyst are recycled, rare earth resources can be recycled, the FCC waste catalyst hazardous waste is safely treated, good economic benefits and environmental protection benefits are achieved, and the requirements of the harmonious social sustainable development are met.

Patent CN106048228A describes a method for recovering rare earth from catalytic cracking waste catalyst, which comprises placing the catalytic cracking waste catalyst containing rare earth in a sulfuric acid solution of 20% -65% at 150 ℃ and 100 ℃ for acid dissolution, then adding ammonia water into the solution to obtain a rare earth enrichment solution, and evaporating water in the enrichment solution by an evaporation method to obtain a sulfuric acid rare earth double salt product, but the method has high temperature and high energy consumption.

Aiming at the current situations that the yield of the FCC spent catalyst is large, the prior art is difficult to process and the processing cost is high, lanthanum and cerium rare earth elements in the FCC spent catalyst are recovered by utilizing an acid leaching-impurity removing-extracting process aiming at the condition that the FCC spent catalyst contains rare earth lanthanum and cerium elements, so that the safe disposal of the FCC spent catalyst is realized, and the resource utilization of dangerous waste of the FCC spent catalyst is also realized.

Disclosure of Invention

The invention aims to solve the technical problems that the FCC spent catalyst in the prior art is difficult to treat in an environment-friendly way, has high treatment cost and low recovery rate, provides a novel method for recovering rare earth lanthanum and cerium from the FCC spent catalyst, and has the advantages of easy environment-friendly treatment, low treatment cost and high recovery rate of the FCC spent catalyst.

In order to solve the problems, the technical scheme adopted by the invention is as follows: a method for recovering rare earth lanthanum and cerium from FCC spent catalyst comprises using acid solution as extractant, leaching rare earth elements in the spent catalyst into the solution by using acid at a certain temperature and concentration to obtain leachate containing rare earth, removing aluminum and silicon from the leachate to obtain purified rare earth solution, and then extracting and back-extracting to obtain pure rare earth solution.

In the above technical solution, preferably, the FCC waste catalyst is a waste equilibrium agent directly discharged from the catalytic cracking unit, and has a particle size of 30-150 μm and an average particle size of 60-90 μm.

In the above technical scheme, preferably, the acid solution is nitric acid, sulfuric acid or hydrochloric acid solution, the concentration of the acid solution is 0.5-8mol/L, and the liquid-solid volume ratio of the acid solution to the waste catalyst is 2-10: 1.

In the above technical solution, more preferably, the acid solution is a nitric acid or hydrochloric acid solution, the concentration of the acid solution is 1-4mol/L, and the liquid-solid volume ratio of the acid solution to the waste catalyst is 5-8: 1.

In the technical scheme, preferably, the leaching time is 1-24h, the leaching temperature is 25-95 ℃, and the stirring speed in the leaching process is 0-500 r/min.

In the technical scheme, more preferably, the leaching time is 6-10h, the leaching temperature is 50-85 ℃, and the stirring speed in the leaching process is 80-200 r/min.

In the above technical scheme, preferably, the leachate is slowly added into a NaOH solution, stirring is carried out while adding, and then the filtrate is filtered, drained and dried to obtain a rare earth filter cake rich in aluminum removed; completely dissolving the filter cake after removing aluminum and drying by hydrochloric acid solution, heating, standing and cooling, and filtering to obtain a rare earth-rich solution after removing silicon; the volume ratio of the leaching solution to the NaOH solution is 2-5: 1.

In the above technical scheme, preferably, a proper extractant is selected, the concentration of the extractant is adjusted, the pH value and the phase ratio of the rare earth-rich solution after silicon removal are adjusted to obtain an extraction liquid rich in rare earth, and then a pure rare earth solution is obtained by back extraction; the extraction agent selected in the extraction process is P204 or P507, the volume fraction of the extraction agent is 5-70%, the pH of the rare earth-rich solution after silicon removal is adjusted to be 1-4, and the extraction ratio is 1:2 to 4: 1.

In the technical scheme, more preferably, the extractant selected in the extraction process is P507, the volume fraction of the extractant is 50-70%, the pH of the rare earth-rich solution after silicon removal is adjusted to 2-3, and the extraction ratio is 2-3: 1.

In the technical scheme, more preferably, the extractant selected in the extraction process is P507, the volume fraction of the extractant is 55-60%, the pH of the rare earth-rich solution after silicon removal is adjusted to 2-3, and the extraction ratio is 2.5-3: 1.

The invention relates to a method for extracting rare earth elements of lanthanum and cerium in FCC spent catalyst by using low-temperature acid leaching-impurity removal-extraction process, which takes acid solution as extractant, and uses acid to leach rare earth elements in the spent catalyst into the solution at a certain temperature and concentration to obtain leachate containing rare earth. In order to improve the recovery rate and purity of the rare earth, the leachate is subjected to aluminum and silicon removal to obtain a purified rare earth solution, and then the purified rare earth solution is obtained through extraction and back extraction. The method has high rare earth element recovery rate and high product purity, realizes the resource utilization of the FCC spent catalyst hazardous waste, can generate better economic benefit and social benefit, and obtains better technical effect.

The present invention will be further illustrated by the following examples, but is not limited to these examples.

Detailed Description