How to Prepare Thin Rock Sections
In this recommended method of preparing a thin section the operator begins by obtaining a rock slice approximately 1 inch in diameter and 1/8 inch thick. The rock slice is ground on the coarse and fine grinding laps until a flat surface without visible pits is produced on one side. An important step in the […]
How to Make Chromium Metal – Metallurgy
Aluminothermic or silicothermic processes used for the metallurgical production of chromium metal from chromium oxide yield a metal that may contain more than 99 percent chromium. A metal of this purity apparently meets all the requirements of the alloy industry, but the price is about three times that of chromium in the form of low-carbon […]
Stone Cutting and Polishing
The mining and fabrication of structural and ornamental stones is a wide-spread industry involving the use of such rocks as granite, limestone, marble, sandstone, and slate. Granite is a medium- to coarse-grained igneous rock comprising chiefly quartz, feldspar, and either mica or hornblende. Limestone is classed as a sedimentary rock consisting essentially of calcium carbonate. […]
Fluorspar Beneficiation Process Plant
The Fluorspar Beneficiation Problem Acid grade fluorspar which is in great demand by the chemical and aluminum industries, must contain at least 97.5% CaF2 with not more than 1.5% SiO2 and 0.5% Fe2O3. Often the Silica is limited to 1.2% with penalties starting at 1.0% SiO2. These limitations on grade and impurities require extremely close […]
Refine Zinc from Iron Impurity
A process was developed in which iron-contaminated zinc was refined to readily acceptable purity. Aluminum added to the molten impure metal reacted with the iron, forming a solid intermetallic compound, Fe2Al5, which floated to the surface of the melt. Small amounts of residual aluminum were eliminated from the product easily by fluxing with zinc chloride. […]
How to Recover Lead & Copper from Blast Furnace Matte
This research has shown that & solid waste byproduct from secondary lead smelters can be successfully processed to recover copper and lead that is lost during smelting. The major steps in the process and the products recovered are as follows: Copper and lead sulfides in blast furnace matte are converted to sulfates and iron sulfide […]
Electrorefining Vanadium Scrap
A molten-salt electrorefining process was developed which provides a practical way for reclaiming vanadium from scrap generated in the processing of ductile vanadium into bar, sheet, wire, and other shapes. Refining produced extremely ductile vanadium with a purity range of 99.93 to 99.95 percent. The process was particularly effective in reducing the interstitial elements, carbon, […]
Ball Mill Pulverizing
As in a pilot-plant-scale hammermill, the effect of moisture content in the pulverization of lignite in a similar size ball mill was observed to be a highly significant factor with respect to power required and in pulverization capacity. Both predrying before pulverization and drying in the mill were found to be highly beneficial in pulverization […]
Fluorine Determination Method
Coal normally contains trace amounts of fluorine ranging up to about 0.02 percent. These small quantities of fluorine generally are volatilized when coal is burned in boiler furnaces. but they may be a transient factor in some types of corrosion and occasionally in deposit formation, and may contribute to atmospheric pollution. A standard method is […]
Vacuum Arc Melting
During the past decade, several novel melting and casting techniques including vacuum arc melting, skull casting, Hopkins’ Process or electroslag melting, and electron-beam melting have been developed on an industrial scale. All of these techniques employ a water-cooled crucible. Heat transfer during vacuum-arc melting with water-cooled crucibles has been studied on a theoretical bases, but […]