Solubility product of iron arsenate and calcium arsenate
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The simplest and most economical way to treat arsenic in arsenic-containing wastewater is by converting it into arsenates. May I ask what the solubility products of ferric arsenate and calcium arsenate are? Which substance is more stable when waste is stored?
Calcium arsenate should be more stable.
Ferric arsenate: green or brown powder. Soluble in hydrochloric acid, insoluble in water and nitric acid. Relative density is 3.18. Melting point decomposition. Refractive indices: 1.765, 1.774, 1.797. Highly toxic! It is highly irritating. Calcium arsenate: Properties: The product is a mixture of various calcium arsenate salts, including CaHAsO4, Ca5H2(AsO4)4, Ca3(AsO4)2, 3Ca(AsO4)2·Ca(OH)2, Ca(OH)2, and CaCO3. A white solid; industrial versions appear red due to the presence of impurities. Density is 3.62 g/cm3. Slightly soluble in water, soluble in dilute acids. Toxic! LD5020mg/kg。 Arsenate insecticides, which appeared in the early 20th century, can be produced by reacting arsenic acid solution with lime milk. It exerts a stomach poison effect on pests and is used to control pests with chewing mouthparts. Although both of these substances are insoluble in water, with calcium salts having an even lower solubility, they are both toxic and unstable. Therefore, precipitation methods are generally not used for arsenic removal; instead, oxidation methods are employed.
Calcium iron arsenate is the most stable, with the lowest solubility product