Recovery Of Rare And Valuable Metals From Rare Eare Waste Optical Glass

Rare earth waste optical glass containing30%～60%of rare earth and some valuable elements, is not only beneficial to recycling of rare earth resources, at the same time can reduce environment pollution by heavy metals. In order to realize the sustainable development of rare earth industry, some rare earth solid waste (waste nickel metal hydride batteries, spent polishing powder, magnetic material, waste fluorescent powder, etc.) has been as raw materials for the extraction of rare earth resources. At present, the report is less about recycling rare earth from the research of rare earth waste optical glass, so this study has considerable value and practical significance.In this paper, there are two different types of rare earth optical glass waste for the study. The research content can be divided into three parts, resource characteristics research of rare earth optical glass process waste and acid dissolve; the recycling of rare earth elements and the separation of niobium and zirconium.The resource characteristics results demonstrated that the spent rare earths catalysts are not belong to dangerous abandon materials.Hydrochloric is used to leach rare earths of the two different types of rare earth waste optical glass; the optimum experimental conditions of orthogonal test are as the following. A-rare earth waste optical glass, the concentration of hydrochloric acid, leaching temperature, leaching time and liquid-solid ratio are4mol/L,90℃,4h, and8mL/g, respectively. B-rare earth waste optical glass optimal conditions of leaching rare earths are identified as4M HCl and a liquid-solid ratio of8mL/g at80℃with stirring of300r/min for60min. In their best conditions, the both leaching rate of rare earth elements were over99%. Rare earths can be separated from impurities by oxalic acid precipitation method. The rare earths of filtrate could be precipitated by2times the theoretical addition of oxalic acid. RE2O3was gained through filtration, washing and calcining, its purity was more than99%In the paper the niobium and zirconium hydrolysis solid (obtained of each of10g sample) was dissolved by different quality of oxalic acid and same volume of deionized water under the heating condition. Almost all of the niobium and zirconium could be dissolved when the dosage of H2C2O4is6g, the dissolution rate of niobium and zirconium are99.30%and99.61%, respectively. Niobium is almost insoluble in the solution which includes a large amount of sodium ions, so niobium and zirconium could be separated by applying the nature of niobium. The concentration of niobium and zirconium in the oxalic acid solution, which we gained in the ideal situation, are3.97g/L and3.78g/L, respectively. It is appropriate that40g Na2CO3is added in the per litre solution to precipitate niobium. The total recovery of niobium and zirconium were91.68%and99.47%, respectively.