An acid mine drainage sludge sample containing 3.6% Mn, 0.18% Ni, 0.15% Co and 0.39 % Zn was obtained from the central part of West Virginia and leached with sulfuric acid at pH 3 and at room temperature. Air was bubbled through the leach solution to precipitate the iron content from the solution at pH … Read more
The effect of the stability and rheological properties of magnetite dense medium on the separation performance of a 6″ dense medium cyclone (DMC) is studied with the use of fine density tracers. The tests in which different size fractions of magnetite are used to prepare the dense media reveal that at low medium densities (<1.5 … Read more
Efficient filtration of fine kaolin particles plays a crucial role in processing of raw kaolin to a marketable product. Oftentimes, filtration is the rate controlling step of the whole process. As a consequence, plant production is dependent, to a great extent, on the rates being achieved in filtration.. Variation in particle size, coupled with varying … Read more
Aqueous pressure oxidation at low temperature, although desirable from a process engineering and operations point of view, presents unique problems when temperatures approach 160°C (320°F). In developing the pressure oxidation process for the Lone Tree Mine, elemental sulfur formation and agglomeration with pyrite proved to be a problem. The Lone Tree Mine currently operates a … Read more
Roasting of refractory gold ores has the primary goal of oxidizing sulfides and organics to improve gold recoveries prior to leaching. Commercial installations currently utilize bubbling and circulating fluidized beds. The principle of flash roasting is aimed at a more cost effective method of whole ore roasting for large throughput applications. Results of pilot plant … Read more
Gold in primary deposits is generally recovered by dissolution in dilute cyanide solution followed by recovery from solution using zinc cementation or carbon adsorption. The dissolution step can be conducted in heaps, vats, or agitated tanks. Gravity concentration, or an intermediate flotation step is an additional process at some operations. An analysis of the processing … Read more
Increased recycling of waste paper has been emphasized in recent years in both the USA and Canada for environmental and economic reasons. Removal of ink particles from the waste paper pulp is therefore necessary. One of the most promising methods for ink removal is froth flotation. Our study investigated the feasibility of a simplified flotation … Read more
hile particle size is universally acknowledged to be important in optimizing industrial copper sulfide rougher flotation circuits, many of the various interactions that do occur at the industrial level with particle size are still being identified and/or quantified. In order to quantify the data collected, a simple two parameter model for fitting time-recovery data will … Read more
The interest in using halogens for extracting precious metals from ores has increased due to changes in ore characteristics, environmental concerns and regulations. The rediscovery of halogen leaching capability has been the topic of these and other writers. Much work has been done on the performance of bromine, chlorine and iodine. Of these, bromine and … Read more
The dissolution behavior of silver and copper from silver/copper alloys in ammoniacal solutions has been investigated using a rotating disc. Oxygen was used as an oxidant. The effect of composition of alloys, concentration of lixiviants, stirring speed and temperature on the overall dissolution kinetics has been studied. Theoretical Background The dissolution of copper and silver … Read more