process for recovery of metal accessories and squared solids after treatment with waesserigen solutions of chemicals that may austraege solutions

摘要

The liquid adhering to a solid such as a metal which has been treated with a liquid such as an acid, alkali, salt or phosphate solution, is recovered by suspending the solid in a column of ascending saturated steam which is enclosed by side walls and cooled above the solid. In a continuous pickling and phosphating process for steel wire, the wire on leaving the pickling and phosphating bath is passed through an elongated container which has a cooler at the top and a steam jacket at the bottom to boil the water in the container. The steam formed dissolves the acid and salt residues on the wire, collects in the bottom of the container and when the concentration of the solution is equal to that of the pickling bath it is transferred to the bath. Alternatively, the salts may first be crystallized out. Instead of using a separate steam generating container, the articles may be suspended over the pickling or phosphating bath in a frame and surrounded by a column of saturated steam produced by heating the treating bath. The process may also be applied to the recovery of ammonium sulphate from filtered ferric hydroxide, the steam being generated by heating a part of the filtrate in a separate boiler.