Pure rhenium is a refractory metal with a very high melting point of 3180°C. Extraction of rhenium from molybdenite concentrates and other primary sources has been studied for many years. Hydrometallurgical methods using Br2, HNO3, Ca(OH)2, NaOH or Na2CO3 have been investigated. Recently, a new process using halogen salts and ammonium as well as oxygen … Read more
The packed jig is a column filled with corrugated diagonal packing. A slurry of mixed particles, the ore, is fed into the middle of the column. Water enters the column near the bottom as both a steady state and a pulsating flow. The pulsating water sets up a jigging action that interacts with the packing … Read more
We will discuss the fundamental elements of cutoff grade optimization and demonstrate how cutoff grade optimization may improve NPV of a given operation under different scenarios. The first case study is a description of cutoff grade optimization for a gold deposit to be mined in a single push-back with a small mill capacity. The second … Read more
Low-cost oxidation pretreatment technologies are needed in order to economically extract precious metals from refractory sulfidic deposits as the world’s free-milling reserves are consumed. Already, more than one-third of the gold ore reserves in the United States are considered to be refractory. Many of the deeper gold deposits that are currently being discovered, including deeper … Read more
Dynamic tests were conducted in a laboratory continuous thickening system. This system, shown in Figure 1, consists of a 3½ in. (89 mm) ID and 20 in. (508 mm) height lab thickener/clarifier equipped with feed, polymer and underflow pumps, bed level sensor and controller. Rake speed, the gap between the deflector plate and feed pipe, … Read more
The granular media used for the study of soluble manganese removal included natural manganese oxide ore. The manganese oxide ore of South Africa origin obtained from Elkem Company (Marietta, OH) was used as the medium for soluble manganese removal. The raw manganese oxide ore sample was crushed and ground into particles of 1.0-0.425 mm (-No. … Read more
However, in a number of applications, natural zeolites have inherent advantages, not the least of which is that natural zeolites cost much less than the synthetics. Fish and Shellfish Farming: Clinoptilolite (clino) can remove ammonia in aquaculture ponds and tanks. Clino has been successfully used in biofilters, regenerable ion exchange beds and pressure filters; and … Read more
A new procedure for determining the optimum separation for any unit operation. This procedure is based on maximization of the yield index, YI, which is the product of the yield (or valuable recovery) and gangue rejection. In addition, the characteristics of the yield index and the separation efficiency are compared and contrasted. As indicated earlier, … Read more
The phenomena of magnetism is well known. The way in which materials respond to a magnetic field can be predicted and the design of magnet systems is now regularly modelled on computer. The real step forward has been in the use of superconducting wire wound magnets that enable much higher fields to be generated. Conventional … Read more
The unique insolubility of silver chloride makes it possible to readily achieve a distinctive separation of silver from a mixed metal ion acidic solution. Using chloride precipitation with NaCl solution, the plant operation selectively removes all the silver from the pressure leach solution. The chemistry is quite straightforward and effective. As with most processes, it … Read more