Method for precipitating rare earth carbonate

Abstract

The invention relates to a method for precipitating rare earth carbonate, belonging to the field of production technology of rare earth carbonate. The method comprises the following steps of: adding sodium carbonate into rare earth liquid; precipitating the rare earth metal ions until the concentration of the rare earth metal ions in the supernate is 0.2-0.002mol / L; continuously precipitating by taking a sodium bicarbonate solution as a precipitator until the pH value of the supernate is 6-7; and dehydrating the precipitate, and washing to obtain the rare earth carbonate. In the rare earth precipitation process, the rare earth carbonate with low content of calcium oxide and calcium oxide is obtained by combining sodium carbonate and sodium bicarbonate as a precipitator; and after thorough precipitation, the concentration of rare earth ions in the mother liquid is less than 0.0001mol / L.

Description

technical field [0001] The invention relates to a method for precipitating rare earth carbonate and belongs to the technical field of rare earth carbonate production. Background technique [0002] At present, in the production process of rare earth carbonate, in order to avoid the pollution of ammonia nitrogen, soda ash is used as a precipitating agent for the production of lanthanum carbonate, lanthanum cerium carbonate, cerium carbonate, lanthanum cerium carbonate, mixed rare earth carbonate, when calcium in the rare earth feed liquid When the content of magnesium ions is high, in order to avoid co-precipitation of calcium, magnesium ions and rare earth ions in the solution during the precipitation process, the incomplete precipitation of rare earth ions in the rare earth feed solution is often controlled to ensure the content of calcium and magnesium in the product. In the rare earth carbonate obtained by this method, the combined amount of calcium oxide and magnesium oxi...

AI Technical Summary

Problems solved by technology

In the rare earth carbonate obtained by this method, the combined amount of calcium oxide and magnesium oxide is generally more than 0.2%. At the same time, due to the incomplete precipitation of rare earth ions in the rare earth feed liquid, the unprecipitated rare earth ions account for about 1-2% of the total rare earth. This part of rare earth is discharged with the precipitation mother liquor, causing a lot of waste of resources

[0003] Because in the precipitation process, calcium and magnesium ions can co-precipitate with rare earth ions to form calcium carbonate and magnesium carbonate, so that the content of the two in the product is relatively high, and the effective method has not been reported in the corresponding research content and methods at present. failed to get a good solution