Blogs
Copper Oxide In-Situ Leaching Wellfield Design
Table of ContentsComponents of Wellfield DesignGeological ConsiderationsWell Completion MethodsCopper Recovery and Sweep EfficiencyCopper Loadings and Reagent Consumption Copper oxide deposits that may be considered for in situ leaching exist in unique geologic settings, different from uranium deposits. A large number of interrelated factors must be considered in wellfield design. Many of these factors are hard to quantify and are directly
Acid Rain and Smelter Agreement
Table of ContentsCopper Price Changes and ProfitabilityThe Mexican-American Smelter AgreementU.S. Leaching Acid Disposal and Smelter AvoidanceSO2 Pollution ControlImpacts of Early Smelter Closure In July 1985, as the U.S. copper industry contracted and the Mexican industry expanded, a transborder pollution agreement was signed which included smelter air pollution control in the “Gray Triangle”: Cananea, Nacozari and Douglas. Since then the Douglas
Poly-Met Mill Liners for Autogenous and Semiautogenous Grinding Mills
Over 25 years ago, SKEGA pioneered the use of rubber linings in grinding mills and rubber is today widely accepted and almost standard material chosen for Regrind and Secondary Mills. There are, however, only a few Primary Mills in operation with “solid” rubber linings because available materials and designs are often not cost efficient in comparison with steel alloys on
Increase Dissolved Oxygen in Gold Leaching with Hydrogen Peroxide
Improvement of current leaching technology was found necessary when processing ores which are more difficult to leach because they generate highly viscous, air-rejective pulps. Cyanidation of these pulps has to run at low oxygen concentrations if the conventional aeration technique with compressed air is used. Since the dissolution rate of precious metals mainly depends on the concentration of dissolved oxygen
Carbonate Buffer in Soil
Data from analysis of mineralogy, water extracts, and groundwater demonstrate the significance of the neutralization of the acid from the tailings by the carbonate in the soil on the processes of retardation of contaminants. The observed data are consistent with the results of the thermodynamic calculations done with PHREEQE for the concentrations of components exiting the reaction zone. X-ray diffraction
Heap Leach Solution Irrigation
Table of ContentsDrip Tubing InstallationOperational Benefits of Drip Irrigation Drip Irrigation Disadvantages The application of drip irrigation in Heap Leach, has been proven to be a significant improvement over conventional spray irrigation techniques. While still under evaluation, it is evident that the use of drip irrigation will increase the operating time of a heap leach during winter and may significantly reduce operating costs
Vacuum Induction Melting
Table of ContentsIngot MeltingIngot ProcessingPreparation of Test SpecimensTest Procedure and ResultsTensile TestsCharpy V-Notch TestsFatigue Tests The effect of fluoride inclusions on the properties of titanium produced from the Bureau of Mines developed induction slag melting process is of concern to the titanium industry. The objective of the research was to determine the effect of removing the nonconductive molten calcium fluoride
Electrowinning Mercury in Gold Pregnant Solution
Table of ContentsLaboratory InvestigationsElectrolytic Cell DesignTest ProcedureTests Using Steel Wool Cathode Synthetic GoldSynthetic SilverTests Using Mercury-Coated Cathode MaterialsSteel WoolPlatinum FoilCopper PlateCopper WoolTests using Mill Solutions and Mercury-Coated Copper Wool Cathode Many gold-bearing ores in the Western United States also contain small amounts of mercury. The presence of mercury creates potential pollution and health hazards during several steps in gold processing. An
Secondary Copper Converter Dust Metal Recovery using Ammoniacal Carbonate Leaching
Table of ContentsReagents and Flue DustProcedure and Development of Operating ParametersNH3 and CO2 ConcentrationLeach Temperature and TimePulp DensityZinc Required for CementationCementation TemperaturePrecipitation ConditionsRoast Time and TemperatureFinal Operating ParametersFinal Tests of Leaching Procedure Effective recycling or disposal of flue dusts is a continuing problem, particularly for secondary smelters treating low-grade Cu scrap. The Bureau of Mines investigated a variety of flue
Manganese Ore Leaching by Dissolved Sulphur Dioxide
Table of ContentsCharacteristics of Selected DepositsExperimental MethodsBatch-Leaching TestsColumn-Leaching TestsEffect of Solution Application Rate on Mn ExtractionLeaching of Mn MineralsLeaching of Mn OresCosolubilization of Ca and FeInduced Permeability The Bureau of Mines conducted column-leaching tests on 25 domestic Mn ores to determine the feasibility of extracting Mn by in situ or heap leaching with dissolved sulfur dioxide (SO2) solutions. The ores
Aluminium Recycling Furnace Refractories
Table of ContentsMaterials and EquipmentTest ProcedureResults and Discussion We studied the problem of corundum formation on refractory linings in aluminum recycling furnaces. A laboratory test was developed for evaluating refractories in contact with molten recycled aluminum and identifying the mechanism of corundum formation. A test apparatus was designed and constructed to evaluate the performance of refractory samples. Corundum mechanism formation
Electrodewatering of Muds
Table of ContentsExperimental Materials and Sample PreparationElectrodewatering Test ApparatusMethodsPreliminary Electrodewatering TestsElectrodewatering of Red Mud and Black Mudsfrom Simulated Bayer Digestion of Bauxite Research was conducted by the Bureau of Mines to determine the feasibility of using electrokinetic densification to dewater Bayer process red mud, magnetic black mud prepared by pressure digestion of red mud in the presence of ferrous sulfate,
Effect of Fluoride on Slag
Table of ContentsMaterialsProcedureIngot MeltingIngot ProcessingPreparation of Test SpecimensTest Procedure and ResultsFluoride InclusionsMechanical and Fatigue TestingFluoride InclusionsTensile TestsCharpy V-Notch TestsFatigue Tests The effect of fluoride inclusions on the properties of titanium produced from the Bureau of Mines developed induction slag melting process is of concern to members of the titanium industry. The objective of the research was to determine the effect
Corrosion During Ore Grinding
Table of ContentsCorrosion Rate Determinations by Laboratory TestsElectrochemistry of CorrosionLaboratory Test MethodsSynthesis of Ore SlurrySimulation of Abrasive ConditionsDetermination of Potential-Current DataLaboratory Test ResultsCorrosion Rate Measurements in a Copper Ore MillEquipment DesignElectrode AssembliesWiring SystemPotentiostat-Computer for Making Potential-Current ScansCopper Mill Test ResultsComparison of Laboratory and Copper Ore Mill TestsAdvanced Field Test Equipment DesignAnalog-Digital ConversionRadio Transmission of DataData Reception and ProcessingCorrosion Rate Measurements
Mine Waste Tailings Beaching
Table of ContentsMine Survey ProcedureTest ResultsLaboratory Test ProcedureTest ResultsFull-Scale Field Testing ProcedureTest Results The Bureau of Mines surveyed waste disposal sites at 18 metal and non-metal mines and conducted laboratory and full-scale field tests to determine the effects of tailings deposition techniques on physical properties of tailings pond beaches. Survey data included measurements of beach slopes, descriptions of deposition techniques, and measurements of
Modelling Solvent Extraction of Copper in Ammoniacal Systems
Table of ContentsReagents and SolutionsTests and ProceduresShakeout TestsLoading Curve TestsPrecisionMathematical Basis for ModelChemical ReactionsEquilibrium Constants and ExpressionsExtraction EquationsEmpirical Extraction EquationsMechanistic Extraction EquationsSupplemental EquationsSulfate SystemCarbonate SystemModel AlgorithmsFlow ChartsSulfate ModelCarbonate ModelResults and DiscussionLIX 64N ExtractantEmpirical-Based ApproachMechanistic-Based ApproachP5100 ExtractantSummary A mathematical modeling method was developed by the Bureau of Mines for the prediction of the principal equilibrium species in the solvent extraction of
Column Flotation and Bubble Generation
Table of ContentsTest FacilitiesColumn Test Results on Specific OresChromite OreFluorite Mica Beryl Silica OreManganese Oxide OreManganese Crust MaterialHigh-Grade Silver OrePrecious Metals OrePlatinum-Palladium OreMineral Behavior Within the ColumnBubble Generator DevelopmentBubble Generator CapabilitiesParameters Affecting Bubble GenerationBubble Generator ScaleupCommercial Bubble Generator Design As part of its research program on column flotation, we performed studies on (1) column flotation amenability and comparison with conventional
Recovering Lithium from Clays
Table of ContentsWater DisaggregationHydrothermal TreatmentAcid LeachingAcid Pug-Water LeachAlkaline Roast-Water LeachSulfate Roast-Water LeachChloride Roast-Water LeachMultiple-Reagent Roast-Water LeachSulfur Dioxide Atmosphere Roast-Water LeachChlorinating Roast With Hydrochloric AcidLimestone-Gypsum Roast-Water LeachHydrochloric Acid Chlorination Roast-Water Leach ProcessBench-Scale TestingEquipment and ProcedureChlorination with Anhydrous HClSelective Chlorination With HCl-H2O MixturesSelective Chlorination of Clay-CaCO3 Mixtures With HCl-H2OLarge-Scale TestingRoasting Equipment and ProcedureRoast TestsLithium Recovery From CalcineProcess Evaluation and DiscussionLimestone-Gypsum Roast-Water Leach
Electrowinning Tankhouses Air Quality
Table of ContentsVentilationCell Cap Ventilation System Electrowinning is an electrochemical operation employing an anode and cathode immersed in an electrolytic solution containing sulfuric acid and aqueous copper sulfate. When direct electrical current passes between the cathode and anode through the electrolyte, very pure metallic copper is deposited on the surface of the cathode. The process is conducted commercially in electrolytic
Re-agglomeration in Fine Grinding of Coal
There is a growing interest in the use of fine grinding to produce ultrafine particles for applications such as direct firing of micronized coal. It has been long known that the difficulty of grinding increases dramatically with the fineness of the desired product. To some extent this is a direct consequence of the decrease in breakage rate with decreasing particle
Method How to Reduce Ball Mill Wear by Cathodic Protection
The present work was undertaken to develop a method to cathodically protect a ball mill to reduce materials loss from mill liners. The essential science of “Cathodic Protection” is to apply a sufficiently negative potential to a metal in a corrosive environment such that the anodic corrosion rate is reduced to a negligibly small or acceptable value. The metal is
Iodide Pressure Oxidation Gold Leaching – Autoclave
Table of ContentsEffect of stirring speedEffect of temperatureEffect of partial pressure of oxygenEffect of potassium iodide concentrationEffect of pH of iodide solution The pressure oxidation process is especially suitable for the sulfide type of refractory ores. It includes two stages of operation. First, the refractory ore is subjected to an autoclave oxidation. At elevated temperatures usually above 180°C and in
Ammonia Gold Dissolution Leaching
Processes for gold extraction usually depend on how gold is associated with its environment. Although cyanide leaching remains the overwhelming option for the treatment of gold ores, because of its economy and simplicity, it suffers from certain inherent drawbacks such as toxicity, low leaching rate and its inefficiency of treating certain classes of refractory ores. Due to these limitations and