Treatment of phosphate rocks with hydrochloric acid

Phosphate rocks were leached with hydrochloric acid; and radium was removed by co-precipitation with BaSO₄. Uranium and lanthanides were extracted by di(2-ethyl hexyl) phosphoric acid and tributyl phosphate. Phosphoric acid was then separated from calcium chloride solution and other impurities by extraction using undiluted iso-amyl alcohol. Gypsum was precipitated by sulfuric acid to regenerate hydrochloric acid for recycling. Fluorine was precipitated from the initial leach solution as Na₂SiF₆.