Fertilizer values from galvanizer waste

Abstract

The present invention teaches a technique and provides for apparatus eminently useful for the econimic recovery of Fe, Zn, and S from waste galvinizer sulfuric acid and crystals of iron sulfate and zinc sulfate. The technique or method of the instant invention involves the ammoniation of the acid or a solution prepared from such crystals followed by the partial oxidation of the resulting ammoniated suspension to a point where the desired product magnetite is formed in the separated from a marketable solution of ammoniacal zinc sulfate. The effecting of the instant technique requires only a minimal amount of relatively inexpensive equipment and is simply and easily placed into practice by, for example, sparging anhydrous ammonia into a stirred tank of waste acid until the Ph is elevated to about 10. Air can be sparged through the resulting slurry to oxidize the iron in the acid. After a proper incubation period, the desired stable product, e.g., magnetite is desired, which product can thereafter be recovered in a gravity-type separator with the aid of magnetic flux enhancement. Both the heretofore mentioned solid product, magnetite, and liquid product of ammoniacal zinc sulfate are readily marketable items.