A METHOD FOR TOTAL PRECIPITATION OF VALUABLE METALS FROM AN ACID LEACHING SOLUTION.

摘要

A method for the total precipitation of valuable metals from a leaching solution that has been acidified with sulphuric acid and that is substantially free from impurities, by neutralising the solution with lime and/or limestone. Neutralisation is effected in at least two stages, wherewith only partial precipitation is effected in the first stage, and wherewith full precipitation of remaining valuable metal content is effected in the last stage, by adding a surplus of neutralisation agent. Slurry containing precipitates and remaining solid neutralisation agent formed in the last stage in the neutralisation process is returned to the first neutralisation stage, possibly after re-dissolving the slurry in the incoming acid leaching solution. The amount of slurry returned together with any further neutralising agent added manages said partial precipitation of the valuable metal content. Metal hydroxide/gypsum precipitate free from neutralising agent and formed in the first stage is washed and then removed from the process for winning metal therefrom in some known manner.