Decomposition of Rare Earth Concentrate
Rare earth in rare earth, generally difficult to dissolve in water, carbonates, fluoride, phosphate, oxide or silicate and other forms. It is necessary to convert rare earth into a compound dissolved in water or a mineral acid by various chemical changes. After mixing, separating, purifying, concentrating or burning, various mixed rare earth compounds such as mixed rare earth chlorides are prepared as products or separations A single rare earth raw material, such a process known as rare earth concentrate decomposition is also known as pre-treatment.
Decomposition of rare earth concentrates have many methods, in general, can be divided into three categories, namely acid, alkali and chlorination decomposition. Acid decomposition is divided into hydrochloric acid decomposition, sulfuric acid decomposition and hydrofluoric acid decomposition method. Alkaline decomposition is divided into sodium hydroxide decomposition or sodium hydroxide melting or soda roasting and so on. Generally, according to the type of concentrate, grade characteristics, product program, easy to non-rare earth elements of the recovery and comprehensive utilization, conducive to labor and environmental protection, economic rationality and other principles to choose the appropriate process.
Production of rare earth carbonate and rare earth chloride:
This is the rare earth industry in the two main products, in general, there are two main processes to produce these two products.
A process is concentrated sulfuric acid roasting process, that is, rare earth concentrate and sulfuric acid mixed in the rotary kiln roasting. After the leaching of the mine water leaching, the soluble rare earth sulfate into the aqueous solution, called leaching solution. And then to the leaching solution by adding ammonium bicarbonate, the rare earth was carbonate precipitation down, after filtering to be rare earth carbonate.
Another process called caustic soda process, referred to as alkali process. Usually 60% of the rare earth concentrate and concentrated lye mix, melting reaction at high temperatures, rare earth concentrate is broken down, rare earth into rare earth hydroxide, the alkali cake washed with water to remove sodium and excess alkali, and then The washed hydrogenated rare earth is dissolved in hydrochloric acid, the rare earth is dissolved into rare earth chloride solution, the acidity is removed to remove impurities, and the filtered rare earth chloride solution is solidified by solidification.read more: