How to Recover Silver from Waste Photographic Solutions
Metallic displacement-type silver recovery units are economical and practical for use by either large- or small-scale photographic processors. Most photographic processors could significantly increase their income by utilizing a unit of this type. The large-scale processor may find it advantageous to use the metallic displacement-type unit as a scavenger following an electrolytic cell. Electrolytic units […]
Chemiluminescence Detector
Instruments currently in use for routine measurement of ozone in the atmosphere are based on ultraviolet spectrometry, coulometry, or colorimetry. Studies have shown that none of these techniques is completely satisfactory for routine ozone measurement, either because the instruments require an inordinate amount of attention or because they lack the requisite specificity to ozone or […]
Recycling Plastics from City Waste
Nearly 4 billion pounds of plastics were consumed by the packaging industry in 1970, about one-fifth of the total plastics production. Urban refuse from the city of Madison, Wis., was found to contain 2.9 weight-percent plastic before drying and 3.3 weight-percent after drying. Plastic waste is a worldwide problem: urban waste contains about 2 percent […]
How to Recover Cobalt and Nickel from Copper
It is the goal of the Bureau of Mines to help maintain an adequate supply of minerals to meet national economic and strategic needs. Among the activities designed to attain this goal is that of advancing minerals technology by making improvements in metals and minerals processing. Toward that end, the Bureau of Mines has been […]
How to Recover Zinc from Zinc Chloride by Electrolysis
The closure of zinc plants has reduced smelting capacity in the United States from 1,300,000 tons in 1969 to approximately 700,000 tons in 1974. At the same time, U.S. consumption of zinc has increased, as shown in figure 1. As a result, the United States must import over 50 pct of its zinc supply from […]
Scrapped Starter Motors & Alternators Recycling
There are two principal methods in use for processing the 8 million cars that are scrapped annually in the United States. About one-half of the cars are processed by shredding in which automobiles minus radiators, batteries, engines, gas tanks, and seats are ripped into fist-sized chunks and then magnetically separated to produce a ferrous scrap […]
Separation of Copper-Nickel by Flotation and Magnetic Methods
As part of our mission to investigate technology options for the development of domestic mineral resources, conducted tests aimed at separating the copper-nickel values in bulk sulfide mattes into copper-rich and nickel-rich fractions. Resources in the Duluth Gabbro Complex are estimated to be 4.4 billion short tons of mineralized rock grading more than 0.50 pct […]
Roof Bolt Bond Tester
A measured pulse of energy is sent into the bolt by a piezoelectric transducer, and the instrument listens for reflected energy. Where the bolt is properly bonded, the energy passes from the bolt, through the resin, and out into the rock mass. Where proper bonding does not exist, a portion of the energy is reflected […]
Control Acid Mine Drainage
Acid Mine Drainage from underground coal mines and coal refuse piles is one of the most persistent industrial pollution problems in the United States. Pyrite in the coal and overlying strata, when exposed to air and water, oxidizes, producing ferrous ions and sulfuric acid. The ferrous ions are oxidized and produce an hydrated iron oxide […]
Acid Dissolution of Metal & Mineral Samples by Microwave
Objective Reduce the time, complexity and expense of dissolving metal and mineral samples in solution in preparation for chemical analysis. Approach In earlier research, the Bureau of Mines developed a rapid and inexpensive method for the dissolution of mineral and metal samples in plastic pressure bottles heated in a boiling water bath. Using this technique, […]