Carbonate deposition method of crystal type heavy rare earth

Abstract

The invention relates to a method for precipitating crystal heavy-rare-earth carbonate, wherein pH of heavy-rare-earth chlorid solution is adjusted to 5.0 to 5.2 by the 8-10% carbon-ammonia water, adding polyacrylamide saturated-water solution in which the volume is 1-3 per thousand of that of heavy-rare-earth chlorid solution, filtering, and the filtrate is diluted to 0.4 to 0.5 M by water, adding eavy-rare-earth carbonate, as seed crystal, agitating to uniformly mix, then precipitating by 8-10% carbon-ammonia water, ending precipitating when pH is 6.2, adding water to 80-90% of volume of the precipitating container, stopping the press water for 12- 24 hours, washing the precipitate for 2 -3 times, filtrating, and crystal heavy-rare-earth carbonate is obtained. The invention has simple operation, low cost, high yield of heavy-rare-earth and good-quality product which contains low-water and low calcium carbonate, chloride ion or the like, is easy to filtrate, having convenient packaging, stacking and trasportation, and small contamination.

Description

technical field [0001] The invention belongs to the field of nonferrous metal hydrometallurgy, and relates to a method for precipitating crystalline heavy rare earth carbonate. Background technique [0002] The heavy rare earth solution after mixed rare earth grouping, if used as a finished product, needs to undergo precipitation treatment to turn it into a solid phase. At present, there are two main precipitation methods: one is oxalic acid precipitation, which has a better precipitation effect, larger particles, and less impurities in the precipitate, but the price of oxalic acid is high, the toxicity is high, and it will pollute the environment. The solubility of the precipitate is large, which affects the recovery of rare earths. The precipitation rate is high and the difficulty and cost of secondary separation treatment are increased, so it has no practical significance for heavy rare earths with large output and low output value. The other is ammonium carbonate precip...

AI Technical Summary

Problems solved by technology

At present, there are two main precipitation methods: one is oxalic acid precipitation, which has a better precipitation effect, larger particles, and less impurities in the precipitate, but the price of oxalic acid is high, the toxicity is high, and it will pollute the environment. The solubility of the precipitate is large, which affects the recovery of rare earths. The precipitation rate is high and the difficulty and cost of secondary separation treatment are increased, so it has no practical significance for heavy rare earths with large output and low output value

The other is ammonium carbonate precipitation. Its precipitation cost is low, the solubility product of heavy rare earth carbonate is small, the recovery rate of rare earth is high, and the subsequent treatment is convenient. However, due to the characteristics of the heavy rare earth element itself, improper precipitation conditions will cause precipitation. The particles are small, difficult to filter, the product has high moisture content, and impurities such as chloride radicals, calcium, and iron are relatively high, which brings inconvenience to packaging, transportation and use.