Magnetic Separation of Pyrite
Exploratory measurements of the dielectric constant of coal and pyrite indicate that pyrite in coals can be heated selectively. If about 1 percent of the radiation is absorbed in the process, it would be very attractive from a commercial standpoint. The following recommendations are offered. More precise and systematic measurements of the dielectric properties of […]
Smelting low Pyrite Copper Concentrate
A laboratory smelting study was conducted on a copper ore containing chalcocite and native copper to test the technical feasibility of non-pyritic smelting (low pyrite). The results of this investigation led to the following conclusions, based on sulfur and copper recoveries and matte compositions: The concentrate can be effectively smelted when pyrite is replaced by […]
Columbium Alloys
As a continuing endeavor, the Bureau of Mines is developing columbium and tantalum alloys for high-temperature applications. This investigation was undertaken to improve the high-temperature properties displayed by the more common columbium alloys that are commercially available. In a previous investigation beneficial improvements were realized by alloying columbium with elements such as hafnium, tungsten, titanium, […]
Columbium Tantalum Flotation
The purpose of this investigation was to determine the flotation characteristics of important columbium / tantalum ore minerals as a guide for the practical concentration of low-grade columbium ores. Placer deposits amenable to gravity concentration have been the major source of columbium; however, these deposits are limited. Therefore, the future of columbium is dependent upon […]
How to Purify & Concentrate a Manganese Leach Solution
A temperature of 250° to 260° C was found to be satisfactory for simultaneous removal of iron and manganese from the pregnant leach liquor resulting from leaching of low-grade manganese ore. A holding time of about 15 minutes at this temperature was sufficient for maximum iron removal under oxidizing conditions. Using optimum conditions with oxygen […]
How to Identify the Surface Texture of Rock
Model studies, using rock, require carefully prepared specimens. Most preparation procedures use some form of grinding or polishing as the last of several steps. During these steps, particularly the final one, the surface formed acquires a configuration defined as texture. Texture is a composite term identifying the physical features called flaws, lay, waviness, and roughness. […]
Electrorefining Yttrium
Tests on electrorefining of yttrium were performed in LiCl-YCl3 electrolytes at 710° C, and the deposits were subjected to vacuum-distillation at 880°C to remove salt from the metal. A comparison of the analyses of the anode feed and the product metal indicates that all metallic impurities were substantially lowered, but oxygen was reduced appreciably only […]
Chlorination Of Ferrochromium
Low-temperature chlorination of three types of ferrochromium at 340° to 525° C chlorinated an average of 89 percent of the chromium and 95 percent of the iron contents of the feed materials. From 81.9 to 91.6 percent of the iron was removed by sublimation as FeCl3. The reactor product was a free flowing material which […]
Zinc Copper Titanium Alloys Cast
Sound ingots of Zn-Cu-Ti alloys can be semi-continuously cast under appropriate conditions. A modified mold design on a specially constructed, semi-continuous casting stand has permitted casting of ingots having adequate surface quality. With the experimental equipment described, pouring temperatures near 860° F (460° C) produced ingots with better surface quality than when a pouring temperature […]
Ammonium Nitrate ANFO Electric Detonation
Accidental firings of explosive initiators have occurred occasionally with some uncertain correlation to the pneumatic loading of ammonium nitrate-fuel oil (AN-FO) blasting agents. The exact association, if any, between these firings and static electricity is unknown. This report describes the role of pneumatic loaders in generation or transfer of static electricity and discusses the possible […]