| 摘要 |
The present invention process and compositions remove heavy metal ions, such as cadmium, copper, lead, nickel, arsenic, manganese and mercury ions from wet-process phosphoric acid by providing a simple, single-step process that uses relatively small amounts of reagent. The process involves treating either the crude acid prior to gypsum filtration or the filtered acid with an organic precipitating agent composition, precipitating metals such as copper, cadmium, nickel, mercury, zinc, and separating the precipitate by either filtration or flotation, to produce phosphoric acid with reduced levels of the metals. The compositions of the present invention include a diorgano dithiophosphinic acid (or alkali metal or ammonia salts thereof), a first dithiophosphoric acid (or alkali metal or ammonia salts thereof) with alkyl or alkylaryl or aralkyl moieties, and optionally a second diaryl dithiophosphoric acid (or alkali metal or ammonia salts thereof).
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