Abstract: Almost complete elimination of metal ions in aqueous effluents can be effected by treating said effluent with a base and then adding amorphous, hydrated magnesium silicate. This sequential process allows metal ion concentration to be reduced to less than 0.1 part per million while using a fairly small amount of amorphous hydrated magnesium silicate.

Abstract: The recycle stream from chrome tanning baths can be treated with magnesium silicate to reduce the amount of suspended solids. The treated stream can be recycled more times, thereby providing a considerable savings of chrome values.

Abstract: Amorphous, hydrated magnesium silicate is effective in reducing the concentration of various metal ions in aqueous solutions or effluent streams. Both mono- and multi-valent ions can be treated in this manner thereby providing a method of preventing release of metal ions to the environment. The method is especially efficient in removal of chrome values from effluents generated in chrome tanning operations. Efficient adsorption of the chrome requires that the pH of the effluent-magnesium silicate slurry be adjusted to or maintained at a value between 5.3 and 9.8. The chrome value may be recovered from the magnesium silicate by acidification of the complex.