Copper smelting practice has not changed much over the last century. Little attention has been paid to the gas-fired reverberatory furnace because it has traditionally represented only about 10 percent of the total cost of producing copper from its ores. However, the emphasis on air pollution control, fuel shortages, and costs have generated interest in … Read more
In the quest for technological improvements in the extractive metallurgy of zinc, some efforts have been made to develop a one-step pyrometallurgical process for direct reduction of zinc sulfide to metallic zinc. The earliest endeavors were those of Eulenstein in 1912 and Peterson in 1913 who both attempted to reduce zinc sulfide with iron in … Read more
The earliest known specimen of lead, dating from 2000 B.C., is a figurine found near the Dardanelles at the site of the ancient city of Abydos. Since that time, the method for producing lead from its most abundant mineral, galena, has changed very little. Basically, a lead concentrate is mixed with fluxing agents, roasted to … Read more
A kinetic investigation of copper cementation on iron was made to study the effects of deposited copper on the reaction rate. Both the copper deposit attached to the iron and slurried copper particles were considered. The revolving-drum reactor used in this study allowed some of the copper to remain attached to the iron and provided … Read more
Domestically produced primary lead is won from lead sulfide concentrates by a smelting process consisting of sintering, blast furnace reduction with carbon and refining. Unfortunately, this pyrometallurgical practice creates gaseous sulfur oxides and particulate lead, which must be controlled to prevent air pollution. For some smelters, meeting environmental regulations requires production curtailment at times, and … Read more
It does not appear likely that this conveyor-system function requirement can be avoided. The emphasis on the continuous miner performance is necessarily such that the conveyor system must be required to handle any material that is provided by the cutting head. Hence, a slowing down in the rate of advance of the miner to produce … Read more
Demand for lead for transportation uses (1) has continued to grow as requirements for batteries have increased. The quantity of lead used in battery manufacturing has reached a record high, and the recycling and recovery of lead from lead battery scrap represented 56 percent of the total secondary lead recycled in 1972. The two methods … Read more
For several years, the Bureau of Mines has been actively involved in developing techniques for recovering and recycling metals and alloys from industrial scrap, including waste materials generated by the electronics industry. Among the latter materials is tin-lead solder that has become contaminated with gold and other impurities to a point where it no longer … Read more
The leaching solutions circulated at copper dumps in the United States contain an appreciable concentration of aluminum-as much as 5 to 10 grams Al2O3 per liter in some solutions. This aluminum passes through the copper-recovery operations and recirculates to the leach dump. The aluminum concentration in the leach liquor appears to be in an equilibrium … Read more
Most copper is produced from chalcopyrite concentrates by smelting. While smelting is both simple and efficient, it converts the sulfur in the feed concentrate to sulfur dioxide. To meet the ambient standards for this pollutant, as established by the Clean Air Act, the Federal Environmental Protection Agency (EPA) has established a goal for smelters to … Read more