Precipitate coflotation of orthophosphate and fluoride

Orthophosphate and fluoride are simultaneously precipitated from aqueous solution, 5.26 × 10⁻³ M. in each, by La (III). The precipitates are cofloated by the anionic surfactant sodium laurylsulfate, with optimum flotation at pH 4.0 and a stoichiometric lanthanum concentration based on LaPO₄ and LaF₃. Over pH 3.5 to 6.0, better than 95% flotation of the total orthophosphate and precipitated fluoride that‐are present can be floated at a molar sodium laurylsulfate to orthophosphate plus fluoride ratio of 0.023. At lower sodium laurylsulfate concentrations, the flotation decreases at pH 3.5 and 6.0 compared to pH 4.0–5.0; at pH 4.0, an increase in the La(III) concentration decreases the flotation.