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.