Aluminum Chloride Solubility
A research program was conducted to improve processing technology for extracting alumina from nonbauxitic. The success of this program had provided the technology necessary for producing an adequate supply of high-grade alumina from domestic sources, thus meeting national economic and strategic needs relative to aluminum production. The hydrochloric acid process for recovering alumina from low-grade ores is one […]
Aluminum Dross Furnace Salt Slags Processing
Disposal of the salt slag produced during the processing of aluminum dross and scrap is of particular interest to the secondary aluminum industry. Melting of these materials is carried out under a salt flux cover to dissolve the contaminants, mostly aluminum oxide, and to optimize the recovery of aluminum metal. Typically, dross and low-grade scrap […]
pH Control in Solvent Extraction Circuits
The control of pH in solvent extraction circuits is an old technique but one which has a large potential for future use. The equilibrium position of any reaction which has hydrogen or hydroxide ions, either as products or as reactants, can be controlled by pH adjustment. Several examples of reaction types which are important in […]
Improve Heap Leaching Percolation Rate
To insure the continuing viability of the domestic minerals and materials economy and the maintenance of an adequate minerals base, the U.S. Department of the Interior, Bureau of Mines, has been investigating the development of methods for improving gold and silver recovery from low-grade resources. Discoveries during the past decade of numerous low-grade, gold-silver deposits […]
Oxide Copper Leach Modeling
In recent years interest in hydrometallurgy, particularly in the case of in-situ leaching and solution mining has remained at a high level. There are several studies published on the development of scale-up principles. D’Andrea and Runke described research on in-situ copper leaching at the Emerald Isle Mine whose dominant copper mineral is chrysocolla. The program […]
Sulfuric Acid Leaching of Smelter Matte
It has long been recognized that the 9 million tons of lead ore mined annually from Missouri’s Lead Belt (83 pct of the U.S. domestic production) contain significant amounts of nickel and cobalt. Yet, neither of these important commodities is being recovered by the current processing depicted in figure 1. The pyrometallurgical treatment of primary […]
Solvent Extraction Electrowinning VS Cementation: Copper Leaching
In the commercial dump leaching of copper, two methods have been generally accepted as a means for recovering copper from pregnant leach liquors. The oldest and most widely used technique is copper cementation with scrap iron. The newer technique involves solvent extraction and electrowinning. As part of a program to assure adequate domestic supplies of […]
Hydroxyoximes
The kinetics of solvent extraction with hydroxyoximes are complex, involving mass transfer with chemical reaction in a heterogeneous system. One is therefore faced with a wide spectrum of possible behaviour within certain well defined boundary conditions. The extraction rate could be diffusion-controlled under all conditions and would thus depend on the interfacial area, and concentration […]
Heap Leaching Time
All metallurgical reactions are dependent on time, temperature, atmosphere (reducing or oxidising) and particle size. Particle size has been discussed and atmosphere will be discussed later. Temperature in heap leaching is dependent on ambient conditions and rates of reaction are not greatly effected during most of the year. Freezing in a northern climate or high […]
Increase Plant Throughput by Mill Expansion
Shortly after start-up, it was apparent that it would be difficult to obtain the plant design throughput. The ore sample that had been used for grinding test work was found to be much softer than that of the orebody in depth. This had led the designers to design without a crushing stage and to designate […]