Water Filtration by MgO Magnesium Oxide
Suspended solids are a common impurity in mine water. Mines rely mainly on flocculation and settling for solid removal, but this can be unreliable owing to seasonal variation in water temperature, runoff, and changes in the character of ores being mined. Filtration is often needed to provide sufficiently pure water to meet mineral processing requirements […]
Fuse Wire Arc Tester
When certain insulating materials are decomposed by heat, highly explosive gases can be released. These insulating materials cannot be used within enclosures containing high-voltage circuits because they may be subjected to destructive electrical arcing. The commonly used method in the United States for determining if materials are highly resistant to electrical tracking is the CTI. […]
Grinding Mill Liner & Ball Corrosion Rate
Several wear mechanisms act upon the grinding media, including corrosion, abrasion, and impact. The interactions between these wear mechanisms are poorly understood, and much disagreement exists in the technical literature. To determine the extent to which corrosion contributes to total wear in industrial grinding mills, the Bureau of Mines entered into cooperative agreements with two […]
Particle Size Distribution
The use of sieves to separate particulate material into fractions of various sizes has occurred throughout the period of recorded history. Sieving is one of the simplest methods of determining particle size distributions, and is probably used in industrial laboratories more than any other method. It is generally overlooked when carrying out fundamental research, which […]
Sizing and Metallurgical Testing
Size is crucial to virtually all mineral processing A size range in a standard series is generally identified by the bottom size in the range A single size parameter is not enough to define a size distribution Narrow size ranges are generally best for following separation processes Sizes are usually arranged in a ratio series […]
Electromagnetic Separation of Copper Iron Sulphides
Chalcopyrite, sp. gr. 4.15 to 4.3, is too feebly magnetic to be separated raw, and must be roasted to either the magnetic sulphide or the magnetic oxide, these changes taking place in a manner similar to the behavior of pyrite. A one-minute roast at a red heat is sufficient to impart magnetism to chalcopyrite through […]
Electromagnetic Separation Siderite & Blende
The specific gravities of blende (3.9 to 4.2) and siderite (3.7 to 3.9) are almost identical, and they may not be separated by any method based on this property. The most important application of magnetic separation in Europe has been the separation of siderite, or carbonate of iron, from blende. Many important ore bodies carrying […]
Separating Pyrite & Blende Magnetism
The co-occurrence of the sulphides of zinc and iron is frequent; blende and pyrite, or marcasite, are found together in important ore bodies which are worked for the value of the contained zinc, and many lead deposits in their lower horizons carry zinc and iron sulphides. Galena may be separated in the wet way from […]
ASSAYING CYANOGEN BY MERCURIC CHLORIDE
Apparatus, Reagents.—Apparatus as before. For the standard solution, pure HgCl2 is required. For analysis the student may take further portions of the materials used in the last estimation. Method, Reactions.—If to an ammoniaeal solution of KCN a solution of HgCl2, be slowly added, Hg(CN)2, is formed and is soluble in water. When this reaction is […]
ASSAYING CYANOGEN BY SILVER NITRATE
Apparatus, Reagents, etc.—The same as in the last analysis, except that the chromate is not required. For analysis the student may take a solution prepared by the demonstrator, or a sample of ‘ gold ’ cyanide (KCN), which, if the potassium salt, will contain from 95% to 98% KCN. This salt now frequently contains NaCN, […]