New Process and Expert System Design for High Purity Rare Earth Extraction and Separation

Question Number: G1998061301
Project leader: Yan Chunhua, Li Deqian, Zhang Guocheng, Liao Chunsheng
Undertaker: Peking University, Chinese Academy of Sciences Changchun Institute of the Beijing Research Institute of Nonferrous metals
Research period: 1998.08~2003.09

I. The completion of the planned tasks According to the annual plan and expected goals of the “Project Task Book”, the research content and expected goals set in the plan have been fully completed.
(A) rare earth compounds of high purity separation process 1, heavy rare earth (thulium, ytterbium, lutetium and scandium) Extraction of the new system (1) Synthesis of a series of novel extractant having a bifunctional group, in a molecule P507 The methylamine group replaces the original alkyl group, which solves the problem of dimerization of the acidic phosphine extractant itself, thereby lowering the equilibrium acidity of the extraction and achieving low acidity back extraction and improving under the premise of ensuring the separation performance of the heavy rare earth. The regeneration performance of the extracted organic phase makes it possible to produce high-purity heavy rare earths (lanthanum, cerium, lanthanum and cerium) by extraction, and at the same time increase the use efficiency of the extracting agent by more than one time; the research results of this system declare Chinese patents.
(2) On the basis of in-depth study of the equilibrium process of heavy rare earth stripping, the principle of phase transfer catalysis was introduced into the back extraction process of heavy rare earth, and the transfer function of protons by amine extractant and the rare earth of acidic phosphine extractant were proposed. The separation function makes the exchange process of protons and rare earths change from interfacial reaction to homogeneous reaction, which solves the slow exchange rate between heavy rare earth ions and protons between two phases (from 40 minutes to 5 minutes), and the acid extraction efficiency of extractant is low. problem. Thereby, the solvent extraction and separation of high-purity heavy rare earths (铥, 镱, 镥) of the existing extractant system is realized. The research result has not been reported so far and has been applied in industrial production; the result is declared a national patent.
The above results won the second prize of the National Science and Technology Progress Award of the Ministry of Education and the second prize of the National Science and Technology Progress Award.
(3) The Cynaex923, scandium extraction CA-12, CA-100, HAB, HDP, Cyanex302 other new systems, yttrium, lanthanide ions mechanism of mass transfer and kinetics. It is proposed that there is a thermodynamic and kinetic synergistic effect between the extracted substances in a single extractant system. This is in contrast to the traditional synergistic effect that two or more extractant systems are completely different for the synergistic extraction of one substance. The extraction mechanism of this new system was clarified.
2. New process and new process research (1) The production process of high-purity cerium oxide is based on the study of the flow distribution of strontium in various stages of rare earth extraction process and the extraction mechanism of strontium and other rare earths and non-rare earths. The conditions of enrichment and high purification in rare earth ore have formed a process for obtaining high-purity lanthanum products by solvent extraction in the process of rare earth separation, and solved the problem of utilizing resources of strontium associated with rare earth minerals for a long time. The result of the application was filed with a national invention patent entitled "Process for enrichment and preparation of high purity hydrazine using alkoxy substituted acetic acid as an extractant" (Application No. X, Application Date: 2002.8.1).
(2) The extraction and separation process of lanthanum (IV), lanthanum and rare earth (III) in Panxi Rare Earth Mine was based on laboratory simulation test. At the end of 1998, the mixing clarification tank amplification experiment was completed and passed the expert appraisal. In 1999, it was counted by the state. The committee approved the demonstration project for industrialization (4000 tons of concentrate/year). In 2000, the industrial test was completed in Suining, Sichuan, and passed the expert appraisal. The process solves the problem of recycling and utilization of radioactive element lanthanum in Panxi rare earth mine, and has obtained the national invention patent (Patent No. 6.).
(3) HAB double solvent extraction and separation of high purity bismuth process Based on the laboratory simulation test, the semi-industrial experiment was completed in Jiangxi in December 1999, and the invention patent (patent application No.8) was applied. It was adopted in Beijing in 2000. Expert identification. In 2001, it was approved by the State Planning Commission as an industrialization project. The process solves the problem that the one-step extraction of high-purity lanthanum requires strict requirements on rare earth components and non-rare earth impurities of the raw materials, and has strong adaptability.
(4) Preparation of high-purity electrolytic reduction process is made short process europium oxide cascade box electrolytic reduction apparatus for processing a europium-containing rare earth chloride solution techniques. Membrane separation electrolytic reduction instead of the classic zinc powder reduction method can eliminate Zn on europium oxide, improve product quality, high purity of 99.999% or more, but also become more continuous production. The world's largest production line of 18 tons of high-purity cerium oxide has been built in Gansu. The results were identified in 2003.
(5) Baotou Rare Earth Mine Clean Metallurgical Separation Process [next]
In 2001, the problem of effective recovery of antimony and fluorine in concentrated roasting of Baotou rare earth concentrate was reported. Completed the laboratory research of “extraction separation and extraction of rare earth cleaning process” and applied for invention patent (patent application No. 4). It provided the basis for the feasibility study of the project. In 2002, it was approved by the State Planning Commission as an industrialization project. In order to provide optimized process design parameters for 40,000 tons of industrialization projects, we proposed the establishment of a 2000-ton industrial scale demonstration project and the 2002 863 clean production project.
(II) Design of rare earth separation expert system 1. On-line analysis method of 241Am-EDXRF On the basis of establishing 241Am-EDXRF online analysis device, the absorption function is introduced to correct Compton scattering and absorption of each element including self-absorption, so that analysis The precision is greatly improved and the analysis object is expanded. The method of the research of this subject can be used to quickly analyze the rare earth elements with a concentration of 1~200 g/L. The relative error is <5% (rare earth concentration <5g/L), 1% (rare earth concentration > 10g / L), this analysis accuracy is similar to X-ray fluorescence analysis, is the best accuracy reported so far. Because the analysis equipment is simple, easy to operate, and fast (the measurement time of each element is less than 1 minute), it fully meets the online analysis requirements of the rare earth separation process. At the same time, the direct analysis method of rare earth elements in the organic phase was successfully studied, so that the analysis method can directly analyze the organic phase-loaded rare earth, thereby expanding the analysis object and species, and the result has not been reported so far.
2. Non-constant mixed extraction ratio system Cascade extraction theory Based on the in-depth study of the exchange between rare earth ions and protons and the extraction mechanism in the current acid extractant system, the exchange equilibrium process between protons and rare earth ions is introduced into the rare earth cascade. The extraction process was calculated, and a cascade extraction calculation model of the acid-containing system (non-constant mixed extraction ratio system) was established and a calculation program was developed, which extended the cascade extraction theory from a pure calculation method to a chemical process. Process design calculations. This theory has important theoretical guidance in the optimization of heavy rare earth separation and stripping processes and process linkage.
3. Development of control scheme, control software and expert system (1) A new cascade extraction simulation model was proposed, in which the mixing-clarification chamber structure of the actual extraction tank and the material operation therein were considered. Compared to the traditional funnel method model, the dynamic process in the actual extraction tank can be more realistically simulated. At the same time, the enhanced Newton method is used to speed up the calculation. The method of attenuation integral feedback is used to automatically control the input flow, which reduces the time for dynamic simulation to reach steady state. The calculation program and interface design are completed, and the software has strong practicability;
(2) Solved the static design problem of multi-component multi-outlet fractionation extraction system. For complex cascade extraction systems with multiple components and multiple outlets, the previous method is to use dynamic simulation to make the system reach equilibrium state, and then study its law, which takes a very long time. The static design method can quickly solve the equilibrium state of the system under a given flow condition. According to the rare earth composition and separation requirements of the raw materials, the number of stages required for separation and the flow rate setting can be quickly solved. Completed the program main body and related interface design, which has certain theoretical value and strong practical significance;
(3) The design of linkage program proposes the concept of fuzzy extraction, which fully interconnects the separation process of segmentation and greatly utilizes reagent chemical energy. Based on the analysis of various separation processes of major rare earth minerals in China (the fluorocarbon strontium, monazite and ion-adsorbed ore) of Baotou and Suining, the fluorocarbon antimony ore and ion-adsorbed rare earth were designed respectively. A new process connection method for the complete separation process of mineral raw materials, which can effectively reduce the acid-base consumption of the whole separation process and reduce the acid and ammonium ion content in the wastewater, thereby not only greatly reducing the separation cost, but also having an important environmental value. The above method has been started in the annual processing of 8,000 tons of rare earth mining and smelting separation process of Sichuan Funing Rare Earth New Materials Co., Ltd., and the annual processing of 3,000 tons of rare earth oxides in the southern mine of Jiangsu Luoyang Fangzheng Rare Earth New Materials Co., Ltd. run. The results show that the application of the new technology can reduce acid consumption by more than 30%, save more than 10,000 tons of hydrochloric acid per year, and 10,000 tons of liquid alkali. The ammonia nitrogen, salinity and wastewater in wastewater can be greatly reduced, with significant The advantages of cost and environmental benefits. It is currently being further promoted nationwide. This is of great significance for improving the separation efficiency, scale and intensification of rare earths in China. The design method greatly exerts the overall benefits of the system through the coordination of multi-element complex systems. In the rare earth separation system, not only the theoretical breakthrough, but also the environmental protection to a "zero emission" clean production has made a big step.
(III) Preparation and properties of functional materials of rare earth compounds On the basis of the above-mentioned separation chemistry and technology research, we have carried out research on functional materials based on ruthenium for the production and accumulation of light rare earth products in China. In the fields of electrolyte materials, electronic devices and high-performance polishing materials required for large-scale integrated circuit chips, the research focuses on the preparation of rare earth doped zirconia systems and small particles of cerium oxide and their films, powders and colloids. Methods and functions. The results show that oxides and hydroxides with different particle sizes can be controlled in a range of several nanometers to several tens of nanometers under mild conditions. In the rare earth doped zirconia nano-film and particle system, the important phenomenon of grain boundary conductivity enhancement is observed, and the strengthening mechanism is given, which is of great significance for exploring the value of the above rare earth elements and improving the functional properties.
Meanwhile, when selecting the item not covered by the project, but the specific nature of the international horizon just rare earth and transition metal-doped cobalt spinel ferrite in the magneto-optical recording area, carried doped cobalt ferrite nano Synthesis and magneto-optical properties of crystalline films. Systematic and in-depth study of the phase formation, particle size and film thickness control methods of different rare earth and transition metal doped cobalt spinel ferrites, as well as the magnetic and magneto-optical properties of the materials show that the system can be blended Effective control of impurities and enhanced magneto-optical characteristics (the maximum Kerr peak reaches 3°, which is 3 to 5 times stronger than the magneto-optical effect of the existing rare earth-transition metal alloy film, and can move the Kerr peak to a short wavelength, thereby facilitating recording The increase in density), the Curie temperature of the material (adjustable from room temperature to 530 ° C) makes it possible to use it in a new generation of magneto-optical recording materials. More importantly, combined with the molecular orbital theory, the mechanism of the magnetic and magneto-optical properties of this type of system is explained. This research has implications for the development of rare earths in information recording materials.