| 摘要 |
<p>A process of separating phosphoric acid and excess of sulphuric acid from the rare-earth sulphate pulp obtained by decomposing monazite sand with concentrated sulphuric acid comprises introducing the pulp into aliphatic alcohols or ketones, preferably at a low temperature, for example 0 DEG C., separating from the liquid the undissolved sulphates, and washing and drying them. Examples relate to the use of methanol and acetone, these liquids being also employed in the respective washing operations. Drying is effected at 100 DEG C. The alcohol or ketone is recovered from the acid-containing liquid by distillation after neutralization with sodium carbonate or lime. The dried sulphates may be dissolved in water at 0 DEG C., and the rare earths isolated in known manner.</p> |
