稀土生产与分离（The production and separation of rare earth）.docVIP

稀土生产与分离（The production and separation of rare earth） Production of rare earth carbonate and rare earth chloride: The two major primary products in the rare earth industry, generally speaking, currently have two major processes for producing these two products. A process of concentrated sulfuric acid roasting, namely, mixing rare earth concentrate with sulphuric acid and roasting in a rotary kiln. After roasting the mine water leaching, the Soluble Rare Earth Sulfate enters the water solution and is called leaching solution. Then, the ammonium bicarbonate is added to the leach solution, and the rare earth is precipitated by carbonate, and the rare earth carbonate is obtained after filtration. Another process called caustic soda process, referred to as alkaline process. The general will stir 60% rare earth concentrate and concentrated solution, melting reaction under high temperature, rare earth concentrate can be decomposed into hydrogen, rare earth rare earth oxide, the alkali cake is washed to remove excess salt and alkali, and then washed with rare earth hydroxide and hydrochloric acid dissolution, rare earth rare earth chloride is dissolved into solution, adjusting acid to remove impurities after filtration, rare earth chloride solution was concentrated and crystallized to obtain solid rare earth chloride. 2. Separation of rare earth elements At present, except for Pm, 16 rare earth elements can be purified to 6N (99.9999%) purity. A single pure rare earth element is separated from the rare earth compounds obtained from the decomposition of the rare earth concentrate, and the chemical process is complicated and difficult. There are two main reasons. The physical and chemical properties of a lanthanide are very similar. The radii of most rare earth ions are close to the two neighboring elements, very similar, and all of them are stable trivalent in aqueous solution. Rare earth ions have great affinity with water and are very similar in chemical properties because