Foam fractionation of the ferric oxide‐dodecyl sodium sulphate system

An experimental investigation is presented of the batch foam fractionation‐flotation of a positively‐charged colloid‐anionic surfactant system, to determine the feasibility of the process for the removal of trivalent iron from water supplies. Ferric oxide (trivalent iron) initial concentrations are varied from 17.5 to 219 mg./l., dodecyl sodium sulphate initial concentrations from 10 to 30 mg./l., and nitrogen rates from 600 to 8000 ml./min. Excellent separations of both ferric oxide and DSS are obtained with residual iron concentrations as low as 0.003‐0.031 of initial concentrations around 25 mg./l., depending on the intital concentration of DSS. The residual DSS concentration remains virtually constant. The ferric oxide enrichment ratio is an inverse power function of the initial iron concentration and is maximized at minimum gas rate.