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How Mineral Behave in Grinding Circuit
A closed grinding circuit, typified by a ball mill-cyclone combination, is often required to treat a feed comprised of a variety of minerals of differing properties. Usually, the individual behaviour of the minerals is not assessed, a procedure which requires sizing and metal or mineralogical assaying of each size fraction. Further, sizing is frequently by screening to perhaps 325 mesh
Increasing Grinding Throughput with Grinding Aids
Table of ContentsWet Grinding of OresFluidity Control Using Chemical Additives in the Wet Grinding Laboratory and industrial grinding tests have shown that the process of size reduction can be significantly influenced by chemicals added to the powder or slurry being ground. The terms grinding aid or grinding additive refers to a substance which when mixed into the mill contents causes
How to Calculate an Open Pit Mine Capacity
Table of ContentsTrucks’ waiting timesActivity times and their standard deviationsDistribution of shovels and trucks The calculation of open pit operations’ capacities has been the subject of many studies using computer simulations. The common problems of simulation are that if one desires a realistic picture of an operation the programming work becomes long and expensive and that the program requires a
Calculating Mass Flow Balances
Table of ContentsMathematical Formulation of the ProblemSolution of the Mathematical FormProgram Description Calculating material flows from analytical data by means of the standard two-product formulas grew increasingly difficult and time-consuming as the complexity of the flowsheets increased and as choices between conflicting analytical values had to be made. Mathematical Formulation of the Problem Any metallurgical flowsheet can be represented by
Belt Conveyors of Large Carrying Capacity Resistance to Motion
Table of ContentsFrictional Resistance Due to Imprint (Ky1)Belt and Material Flexing Resistance (Ky2 + Ky3) The frictional resistance to motion of a belt conveyor has always been a subject of intensive studies and research by engineers throughout the years. Numerous informations have been developed by analysing series of field tests on belt conveyors of different characteristics and carrying different materials at
Belt Conveyor Drives Factors & Selection
Table of ContentsSoft Start ControlDual DrivesMultiplexing Conveyor Soft-Start Controls Conventional belt conveyors are powered by electric or electro-mechanical drives mounted at the conveyor’s head, tail, intermediate return span, or a combination of these. The following are main elements influencing the selection of the drive system: 1) dynamic characteristics, 2) economic factors such as capital cost, plant spares compatibility, reliability, availability, maintainability,
Ball Mill Charging System
Mill ball charging systems have undergone little change during the past two decades. Most operations utilize a locomotive/ball car combination to load and haul charges from the ball storage bin to the mill charging boxes or, alternatively, transport charges to the charging boxes by means of a ball bucket handled by bridge crane. The grinding section at Island Copper is
Automatic Grinding Mill Control
Table of ContentsPlant DescriptionCommissioning There are presently in use many grinding mill control schemes and concepts. In this case, one operating method of controlling the particle size of the cyclone overflows for proper metallurgical results and controlling the level of the cyclone feed sump and new feed rate to obtain lowest unit cost of finished (ground) material which is usually
Gangue Assay
On-stream analysis is a much more rapid means of obtaining true assays of a flowing product when compared to wet chemistry or “grab” samples dried, briquetted and assayed by x-ray. In contrast, on-stream analysis uses real time samples assayed every 30 seconds while each stream is assayed every 5 to 15 minutes. The main physical and chemical factors which influence
Copper Sulfide Leaching by Ammoniac to recover Sulfur
Results of a preliminary study of the ammoniacal leaching of covellite (CuS) in an aqueous oxidizing system in the presence of a non-miscible organic sulfur solvent are described. Up to 60% of the sulfur can be recovered from the solvent as elemental sulfur while achieving high degrees of solubilization of the mineral. Experimental Leaching tests, both with and without an
Hydrometallurgical Copper Extraction Process
The successful development of the Cyprus Copper Process has been an evolutionary series of events covering a time span of some seven years. What does the Cyprus Copper Process do? Very simply, it converts copper concentrates of varying composition into copper metal which has been proven to be equivalent in every way to electrolytic tough pitch copper suitable for electrical applications.
Sulfide Ion Leaching Kinetic of Wulfenite
The principle oxide minerals of molybdenum are wulfenite (PbMoO4), ferrimolybdite (Fe2(MoO4)3·nH2O), powellite (CaMoO4), and ilsemannite (Mo3O4). Wulfenite is found in Arizona, New Mexico, Nevada, Utah, California, and Montana. It is also found in the states of Sonora and Chihuahua, Mexico. Prior to 1915 wulfenite ores were the primary source of molybdenum. All leaching experiments were performed in a thermostated glass
Vor-Siv Dewatering & Classifying Device
The Vor-Siv Dewatering and Classifying Unit was developed by the Polish Coal Industry because of a need for a unit that would dewater and classify high volumes of solids in water slurry. To be practical, the unit needed to be relatively small in size, simple in design, involve low operating costs, and be able to give a dewatered product of
High Waste Dump Stability
Table of ContentsDevelopment of Foundation FailureModeling and Monitoring ProgramsMonitoringFailure of Copper Notch Dump The height, structure, rapid rate of growth, and anticipated leaching suggested the possibility of dump failure. In order to evaluate this possibility, an outside consulting firm was retained in 1966 to investigate the stability of the growing dumps. Their investigation indicated that, other than superficial movement, the
How to Recover Zinc from Zinc Chloride by Electrolysis
Table of ContentsExperimental ProcedureInvestigation of VariablesElectrolyte Composition and TemperatureEffect of ZnCl2 ConcentrationNaCl-ZnCl2 SystemKCl-ZnCl2 SystemLiCl-ZnCl2 SystemKCl -LiCl -ZnCl2 SystemCurrent Density and Electrode SpacingMetal PurityConclusions 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
Flotation Reagent Manufacturing
Manufacture and mixing of flotation reagents at the mill site provides an economic and convenient method of maintaining a continuous and fresh supply of reagents for concentrator operations. Kennecott Copper Corporation has designed and built a Reagent Mixing Facility which incorporates new ideas in construction and fail-safe operation at its Nevada Mines Division concentrator. Reagents used at the McGill concentrator
Optimising Ball Mill Liners to Maximise Tonnage
Mill liner design is an important factor in grinding. Testing and selection of the optimum liner profile for a given set of mill operating conditions can improve mill capacity, liner life, and liner wear rate. In testing four mill liner profiles for 13′ x 12′ overflow ball mills. Climax found that an improved design increased mill tonnage by 3 tons
Scrapped Starter Motors & Alternators Recycling
Table of ContentsStartersGeneratorsAlternatorsDismantling of Starters and Generators 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
How to Grind Finer
The minntac complex is a facility for production of iron ore pellets located on the mesabi range at mountain iron, minnesota. It consists basically of a mine, crushing plant, concentrator, and a pelletizer producing twelve and one-half million tons of pellets annually. This paper deals with some of the aspects of the grinding circuits; but prior to that discussion, it
Hydrochloric Acid Copper Leaching
Table of ContentsPertinent Chemistry and MineralogyPreliminary Process ConsiderationsExperimental Data Experimentation with chalcopyrite concentrate in dilute hydrochloric acid, under reflux conditions (in Pyrex flasks) and with an inert purge gas, revealed substantial amounts of H2S production and iron solubilization, with negligible copper solubilization, after 2½-4 days. Under comparable condition the extent of reaction with dilute sulfuric, acetic and phosphoric acids was
Magnetic Filtration of Kaolin Clay
Table of ContentsThe Development of HEMF EquipmentDescription of HEMF EquipmentUtilization in Kaolin The kaolin development brings together for the first time four concepts that make practical large scale use of high extraction magnetic filtration (HEMF). These include retention time, extreme gradients, high intensity fields, and efficient design of large high field magnets. Each of these elements was known and available
Handling Sticky Flotation Concentrates
Table of ContentsHandling Characteristics“Ideal” Belt Conveyor Chute Design – Wet Concentrate“Modified Ideal” Conveyor Chute Design – Wet ConcentrateBelt Conveyor Chute Design – “Bone Dry” ConcentratesBelt Conveyor Design EconomicsFilling of Bins and Storage Files with Wet Concentrate The passage of an ore pulp through the froth flotation process results in the production, after dewatering, of a finely divided concentrate. This intermediate
Effect Grinding Media on Selective Flotation of Copper Lead Zinc
The normal practice for processing complex sulphide ore has been to grind with steel balls and/or rods in steel mills before flotation. Little thought had been given to the effect of grinding media on flotation selectivity of copper – lead zinc ore. Ore Sample The mill feed for the pilot-plant investigation was from a copper-zinc producing mine in northwestern Quebec.
How Rotary & Spray Drying of Copper Concentrate Compares
The rotary drying system consists of a final concentrate thickener to dewater the slurry to about 60%-70% solids; a vacuum filter (disc or drum) with the necessary vacuum pumps to dewater the thickened material further to about 14%-20% moisture on a dry basis; a collecting belt underneath the filter to receive the filter cake; a stainless steel type ribbon screw