Preparation of double salts of rareearths sulfate

The research of new agricultural double salts of rareearths sulfate is described. The effects of some technical parameters such as particle size, temperature, pH value and liquid solid ratio etc on the raw material conversion rate, as well as product recovery rate, are investigated. A conversion rate of no less than 98% is achieved at the following process parameters: the size in 100% 0.175 mm, reaction at 65℃, pH at 5.5 and liquid solid ratio at 7. The process is simple and there is no waste to be discharged. The product is of anti moisture, easy matched, moderate solubility, slow release and low cost, without the shortages of that of nitrate rare earth and chloridate rare earth. The field trials show the yields increase on rape by 11.47% and paddy by 8.7%.