Brown and Caldwell Home Page
Technical Papers RECENT PAPERS    ALL PAPERS      LOG IN

Brown and Caldwell engineers and scientists are technical and thought leaders in the environmental sector. Meet the people who have been advancing innovation for more than 70 years.
Author      Title/Abstract      

Recovery and Recycling of Spent Acids in the Metals Processing Industry
Author: Dhiru Patel, Steven J. Pratt

Many companies generate large amounts of concentrated acid wastes. Facilities which process metals are very concerned about this problem. A typical process is that of a steel finishing company's pickling line. In a typical line, the iron oxides are removed from the steel in hydrochloric (HCl) or sulfuric (H2SO4) acid pickling baths. Then the processed steel from the pickle baths is washed in rinsing baths to remove excess acid and wash away the salts. Spent pickling bath acid (saturated with salts) is generally sent to a storage tank for eventual transportation to an offsite treatment or disposal facility. The acidic rinse water is usually stored separately and treated by precipitation processes prior to discharge to the sanitary sewer.