关键工程管理国际学术研讨会

1、Recovery of Rare Earth and Cobalt from Co-based Magnetic ScrapsXu Taoi,2, Zhang Xiao-dong3(1 Baotou Research Institute of Rare Earth , Baotou 014030,ChinaNational Engineering Research Center of Rare Earth Metallurgy and Functional Materials,Baotou 014030,ChinaAbstract:Inner Mongolia Baotou Steel Rar

2、e Earth Hi-Tech CO., LTD., Baotou 014030,China)The reuse of RE and cobalt in Co-based magnetic scraps was studied.Making sure feat lixiviated condition is that: 200 mesh, sulfuric acid dosage of 1.4 times theoretic dosage, temperature 90 C, leaching time 1h. The result indicated that lixiviate rate

3、of cobalt and rare earth attained 97.8%, 99.6% respectively. The optimum technology conditions was:Na2S2O8 dosage of 8 times theoretic dosage, oxidation temperature 80 C, oxidation time 2 hour, pH=4.5.Rare earth was precipitated by saturated (NH4)2C2O4 solution, after roasting of rare earth oxalate,

4、 received rare earth oxide. The samarium and gadolinium sum recovery was 96%, 92% respectively. Cobalt-iron residue was soaked by hydrochloric acid, the Fe(OH)3 was preferential solution, pH was adjusted to 1.4 by hydrochloric acid, Co(OH)3 does not dissolved, Cobalt and iron were separated, after r

5、oasting of Co(OH) 3,received cobalt oxide. The total recovery of cobalt was found to be 97% and rare earths was 96%.Keywords: cobalt-based magnetic scrap; cobalt; rare earthCLC number: TE992.3Document code: ASmCo alloy was 70 years of the 20th century developed a new type of permanent magnetic mater

6、ials, because of its high Curie temperature, temperature stability, corrosion resistance and good oxidation resistance, the advantages of the permanent magnet material has an irreplaceable role, so since the advent of SmCo permanent magnet get wide attention. The material in microwave communication

7、technology, audio-visual technology, electrical engineering, instrumentation technology, computing technology, automation technology, transportation, petrochemicals, magnetic technology, magnetic separation technology, biological engineering and magnetic fields of medical and fitness equipment is wi

8、dely used The materials have already become an important material foundation of new technologies 1. Permanent magnet material in the molding process, 20 to 30% of scrap material and discarded as waste, extraction of cobalt and rare earth, can recycling 2 6. By extraction and precipitation 7 The rare

9、 earth permanent magnet rare earth elements in industrial waste recycling and cobalt have been reported, Zhang Xiaodong and others 8 The cobalt-based alloy material waste comprehensive utilization of resources were reviewed, studied co-based magnetic scrap leaching conditions and recovery of rare ea

10、rth oxide and cobalt separation process conditions.1 ExperimentalMaterials and instrumentCobalt-based magnetic scrap was the main material used in this experiment. And experimental water are deionized water, all reagents were of analytical grade.ICP-AES (US Varian, Inc)Experimental methodsElements o

11、f the leaching experimentTable 1 Chemical composition of the SmCo magnetic scraps (mass fraction, %)ElementSmCoFeGdContent21.6249.8016.044.34Accurately weighed 20g sample dissolved with 2moLH 2SO4, impact of sample on leaching of elements in the main factors size, amount of sulfuric acid, temperatur

12、e and time of each experiment.Oxidation of cobalt and iron to precipitate into purpose and RE separationTake 100mL the leaching solution into the 500mL beaker, Co 2+ and Fe 2+ were oxidized to C03+ and Fe3+ with Na2S2O8 in leaching solution, to be obtained Co(OH) 3 and Fe(OH)3. After filtration, rar

13、e earth 、 cobalt and iron separation. Cobalt and iron in solution and precipitation were analyzed, in order to express the rate of precipitation of cobalt and iron, and the separation between the three metals. Addition of ammonium oxalate in the filtrate after precipitation of rare earth, precipitat

14、ion after washing, drying and roasting were rare earth oxides.Separation of cobalt and ironThe precipitation of Co(OH) 3 and Fe(OH) 3 were dissolved in hydrochloric acid(1moL),then control pH1.4 to be separated cobalt and iron.Detection of elementsThe element was determinated by volumetric method, g

15、ravimetric method and ICP-AES.2 Results and analysisLeaching test results and discussionSize on leaching rateThe different size samples were leached by sulfuric acid, with 1.4 times the theoretical amount of sulfuric acid(2moL), at 80 90 C ,under the leaching time of Ih.The content of samarium gadol

16、inium and cobalt were determinated in solution and residue. Fig.1 shows that, the smaller of samples, the higher the leaching rate.%/eraK gsncaeL000000000009876543210 020406080100 120 140 160 180 200 220 240size/mesh10090/80tRg 70hae 605040 0.91.0 1.1 1.21R1.4 1.51.61.7 1.8sulfuric acid dosageFig.2

17、Effect of multiples of sulfuric acid on leachingFig.1 Effect of size on leaching rateAmount of sulfuric acid on leaching rateThe weight of 20g sample was put forward to the size of 200, was dissolved by sulfuric acid in 80 90 C , under the leaching time of 1h. The times theoretic dosage of sulfuric

18、acid were 1.0、1.1、1.2、1.3、1.4、1.5、1.7 respectively. The content of samarium、gadolinium and cobalt were determinated in solution and residue. Fig.2 shows that, the metal leaching rate increases with the dosage of sulfuric acid, and then reaches its maximum when 1.4 times theoretic dosage of sulfuric acid was put. So choose the