Blogs
Pegmatites Geology
Table of ContentsBeryllium MineralsLithium MineralsTantalum-Columbium MineralsSheet MuscovitePegmatite DepositsDevelopment of Reserves Granitic pegmatite deposits are the chief source of commercial feldspar, sheet mica, beryllium, tantalum-columbium, and lithium minerals, and certain types of kaolin. They also have yielded significant quantities of cassiterite, gems, scrap mica, molybdenite, tungsten minerals, uranium-thorium and rare-earth minerals, and zircon, either directly or as the sources of
Sand and Gravel Jig
In general, the beneficiation of sand and gravel consists of the removal of certain low specific gravity deleterious particles from the sand and gravel. These particles are coal, lignite, ochre, chert, sandstone, wood, clay, shale, and chalk. These deleterious materials almost always have an apparent specific gravity which is less than 2.35 while good sand and gravel has an apparent
Lightweight Aggregates
Table of ContentsStructural Uses of Lightweight AggregatesTypes of AggregatesNaturally Occurring Aggregates Lightweight aggregates have been in use for many years in the United States but are now receiving more and more attention by manufacturers and users of concrete shapes. These shapes comprise building blocks, special forms, such as door sills, lintels, floor slabs, and beams. Lightweight aggregate also is adapted
Potash Mining Methods
Table of ContentsDrilling and BlastingHaulageVentilationPotash Co. of America Commercial beds of sylvite ore were discovered by the Snowden & McSweeney Co. while drilling a wildcat oil well some 25 miles northeast of Carlsbad, N. M., in 1925. After a preliminary core drilling program the U. S. Potash Co. sank a 1060-ft shaft within 4 miles of the original discovery. This
Small Coal Burning Boiler Plant
Table of ContentsAsh HandlingLift Speeds Timber HandlingHardening for Increased Bit LifeCrushing Plant Dust Control at The Ray Mines Division, Kennecott Copper Corp.Transfer StationHousekeeping How much can the mine operator afford to spend on his coal burning boiler plant? The usual answer is as little as possible and still get the job done. Thus, attention must be focused on the spot
The Rupp-Frantz Vibrating Filter
Table of ContentsThe Filter MechanismThe Filter in ActionCapacity of the MachineDewatering Effect One of the chief difficulties with which the operator of a coal washing plant has been forced to contend is the handling of the very fine coal. First he has the problem of separating the fine coal from washery water. This is usually accomplished by the use of
How to Produce Graded Glass Sand by Grinding and Classification
Table of ContentsSand-preparation PracticePresent InvestigationThe Mineral Dressing ProblemChemical TreatmentsAttrition Scrubbing and Grinding The problem of producing a uniform, medium-fine sand for glass-furnace feed has been of interest to the glass-container industry for many years. In the present investigation of the problem, conducted by the Bureau of Mines in cooperation with the Owens-Illinois Glass Co., Alton, Ill., a satisfactory method of
How to Produce Ammonium Sulphate and Manganese Oxides
Manganese Products, Inc. has developed a sulphurous-sulphuric acid leaching process for the recovery of manganese from low-grade, intermediate manganese ores. By the term “intermediate manganese ores” is meant those ores in which the manganese in the form of manganese oxides is found to have two different valences, usually two and four, as is probable in Mn3O4, or the ore may
Leaching Manganese Ore with Caustic Soda
Table of ContentsExperimental ProcedureRegenerating Caustic Leach Liquors All of our larger domestic deposits of manganese are very low grade, but estimated tonnages in these deposits are large enough to constitute a potential strategic reserve of manganese for emergency periods, provided these ores can be upgraded sufficiently to meet industrial specifications. Many types of processes have been suggested for upgrading these
Grinding Circuit Control Strategy
Table of ContentsBall Mill Load Detection SchemeNew feed rate controllerGrind index control strategyBall mill transport index control strategySump level controllerWater flow controller Figure 4 is a schematic diagram of a ball mill/cyclone control system. This diagram shows the instrumentation and the calculated variables used in the control strategies. The prior detailed process analysis study produced two major conclusions: Reduce mill
Adsorption of Sodium Ion on Quartz
When a mineral particle is fractured, bonds between the atoms are broken. The unsatisfied forces that appear at the newly formed surface are considered to be responsible for the adsorption of ions at the mineral surface. A knowledge of the mechanism and extent of ion sorption from solution onto a mineral surface is of interest in the development of the
What are the Applications of Xanthates to Flotation
Table of ContentsDescription of the XanthatesApplicationsDifferential Lead-Zinc MillsCopper MillsDifferential Copper-Zinc Mills Most papers on xanthate have dealt with principles rather than practice. On the assumption that many millmen are interested in knowing where and in what manner the xanthates are being used in mills other than their own, this paper will summarize the results of a recent survey of North
Launder Washers
Table of ContentsThe RheolaveurFree-discharge Rheolaveur for Fine CoalPlant Circuits and Operating ResultsKoppers-Battelle Launder Trough washers were among the earliest methods used for concentrating ores; they are referred to by Agricola about the middle of the sixteenth century as already being used while the hand-operated jigging sieve had only recently come into use. For cleaning coal the trough washer apparently was
Flotation Rates and Flotation Efficiency
The separation of minerals by flotation can be regarded as a rate process, with the extraction of any one mineral determined by its flotation rate, and the grade of concentrate by the relative rates for all the minerals. So regarded, the significant variables for the process are those that control the rates. These variables are of two types, the first
Effect of Flotation Air Bubble Size
A search of the literature reveals that no measurements have been made of the forces acting between a small solid particle whose surface is hydrophobic, and an air bubble to which the solid adheres, both immersed in water. Analyses have been made of the forces acting to support a greased solid on the surface of water, and the forces acting
Physical Metallurgists
Table of ContentsTransformationsAge-HardeningDiffusionPowder MetallurgyTwinningFractureCorrosion During the past year there have been a number of significant investigations that have furnished evidence on the driving forces governing grain growth and on the role played by boundary impurities. Thus Burke has shown that in high-purity alpha brass the rate of grain growth in the earliest stages is approximately inversely proportional to the existing
Precipitation in Copper-Beryllium Alloys
Table of ContentsExperimental TechniqueOrientation RelationshipIntermediate Structure—γ’Discussion of Results The nature of the atomic rearrangement involved in the precipitation of the compound γ-Cu-Be from supersaturated solid solutions of the copper-base alloys has been the subject of two extensive investigations. The precipitate in this alloy system has a rather simple structure; at equilibrium it has a body-centered cubic unit cell with copper
Vapor Pressure of Silver
The purpose of this study was to measure the vapor pressure of silver as the first step in the determination of activities in silver alloys and to test the limitations of the method adopted. In order to work at low pressures, below 2×10-² mm of mercury, the orifice effusion technique was employed. To shorten the time of collection of silver
Solid Copper Surface Tension
G. Kuczynski and B. H. Alexander—This paper represents a most noteworthy attempt to evaluate experimentally the surface tension of a solid metal. Because of the great importance of such measurements, any proposed method should receive the closest scrutiny before the results can be considered reliable. The writers think, however, that the experimental results are fairly reliable, but that there may
Fundamentals of Mixing and Agitation
Table of ContentsFluid MotionFlow Patterns for MixingMixing Requirements for ProcessingPower Required to Drive Impellers Mixers are being applied with increasing frequency to problems in the metallurgical industries. The increase represents in part the modernization of mechanical equipment used through the application of unitized drives, modern electric motors and speed reducers, and recently developed materials of construction. Some applications have resulted
Callow Flotation Cells – Design and Operation
Callow-Type flotation cells, with various modifications, have been employed at the Hayden concentrator since 1917. Other flotation machines, such as matless-air and mechanically agitated types, which have been tested in competition, have failed to handle tonnages or give metallurgical results equal to the modified Callow-type cells on the Ray ores. While experimental work was conducted at Hayden on cell bottoms
Cationic Collector for the Flotation of Quartz
Table of ContentsQuartzCollectorAdsorption TestsVacuum Flotation TestsSolubility of DodecylamineAdsorption IsothermEffect of pH on the Adsorption Density of the CollectorCritical pH CurvesCorrelation of Adsorption Data with Flotation ConditionsA Physical Model of the Quartz-Solution Interface The behavior of collectors at the mineral-solution interfaces is usually explained in terms of an ionic adsorption process. Through the distribution of collector ions between the solid surface
How to Select the Correct Classifier
Table of ContentsUnit-Type ClassifiersThe Bowl ClassifierThe Multi-Deck Washing ClassifierThe HydroseparatorCentrifugal Classifiers Separating a mixture of particle sizes of material suspended in a liquid medium is by no means an exact science. Selecting machines for individual classifying operations is even more difficult. The plant operator’s own background is of course invaluable, and considerable help may be obtained from technical articles, talks
Crushed Limestone Aggregates for Concrete
The problems encountered in efforts to explain the behavior of limestones, dolomites, and related rocks as concrete aggregate lie on the frontiers between the ignorance of the geologists and the ignorance of the engineers. The mineral composition and textures of the rocks have not been adequately explored and described, and the effects of mineral composition and texture on the performance