Miscellaneous - Chlorides - Nonferrous Metals From Pyrite Cinder

At the Duisburger Kupferhütte plant in Germany, pyrite cinder is collected from the sulfuric acid manufacturers in that country and processed to recover the nonferrous metals contained in the cinder, before charging it to the blast furnace for iron recovery. A typical analysis of the cinder is given in Table 9-1. The pyrite cinder is mixed with NaCl and treated continuously in a multiple hearth furnace. The evolved gases are scrubbed with water to form a weak acid which is used for the leaching process. Each batch requires about 2 days for leaching. The concentrated leaching solution obtained in the first 15 to 20 hr is sent for copper recovery, while that subsequently obtained, being poor ill metal content, is recycled. The residue, called purple ore, now a high-grade iron ore (61-63 % Fe); is sintered and delivered to the blast furnace.