Assertion: phosphoric acid's impurity | /r/Desires | separation
Facets:
value: often
type: TEMPORAL
value: prior to its intended use
type: OTHER
Source sentences:
text: In general, silicon, calcium, arsenic, iron, fluorine, aluminum, chromium, vanadium and lead compounds are some of the impurities which often require separation to some degree from the wet phosphoric acid prior to its intended use.