Blogs
Recover Anhydrous ZnCl2 from Aqueous Solutions
Table of ContentsMethods and ProceduresResults and DiscussionScreening TestsSparging TestsEffect of ImpuritiesLime Treatment of Mother LiquorThermal Decomposition of Zn(NH3)2Cl2Process Flowsheet At the present time, zinc is produced commercially by a roast-leach zinc electrowinning process. The primary source is high-grade concentrates of the mineral ZnS. Concentrates must contain low levels of iron to avoid formation of zinc ferrites during roasting because zinc
Solvent Extraction – Predicting Equilibrium Values
Table of ContentsExperimentalReagents and SolutionsTests and ProceduresPrecisionMathematical Basis for ModelExtraction EquationsAqueous Equilibria EquationsEquilibrium Constants and ExpressionsMaterial Balance EquationsComputer ProgramResults and DiscussionConclusions Trends in extractive metallurgy in recent years from milling and smelting of high-grade ores toward heap leaching and electrowinning of low-grade or marginal ores, have resulted in increased reliance on solvent extraction as a key part of profitable operations.
Multi-timbered Wood Crib Supports
Table of ContentsGeneralized Wood Crib BehaviorCompression CharacteristicsBuckling CharacteristicsLocalized Behavior CharacteristicsStiffness CharacteristicsLoad Rate CharacteristicsWood Pack Wall Test ResultsCrib Deformation AnalysisStiffness CharacteristicsEnergy AbsorptionCost Benefit AnalysisUnderground Observations Wood cribs are used extensively by the coal mining industry in a variety of applications to stabilize mine openings. The U.S. Bureau of Mines is conducting research to evaluate the load-displacement characteristics of active and passive
Biosorption of Metal Contaminants Using Immobilized Biomass
Table of ContentsFabrication of Bio-Fix BeadsIdentification of Bead Fabrication ParametersSelection of BiomassStandard Bead Fabrication ProcedureBio-Fix Bead Sorption and Elution CharacteristicsMetal Sorption from Dilute Waste WatersMetal Sorption KineticsEffect of pH on Metal SorptionSorption of Calcium and Magnesium IonsElution and Regeneration of Bio-Fix BeadsStability of BIO-FIX BeadsBIO-FIX Bead ApplicationsContinuous Column TestPassive System TechnologySecondary Treatment of Waste WatersSummary and Conclusions The removal of
Cyanide Leach in Cold Temperatures
Table of ContentsAcknowledgmentsHistory of Cyanide UseCyanide ChemistryCyanide Heap LeachingEnvironmental FactorsAlaskan ConsiderationsCost AnalysesNevada Mine ModelsAlaska Mine ModelsNevada Mill ModelsAlaska Mill ModelsRecoverable Metal ValueSummaryAppendix – Summary of Capital and Operating Costs for Alaska and Nevada Mine/Mill Models. In October of 1987, the U.S. Bureau of Mines (Bureau) initiated a study on the applicability of cyanide technology to the Alaska mineral industry. The
Tin Tungsten Mineralization
Table of ContentsAcknowledgmentsGeographic Location and AccessGeologySurficial GeologyRegional GeologyLocal GeologyIgneous PetrologyBiotite GraniteBiotite-Muscovite GraniteZinnwaldite GraniteDike rocksMineralizationDeposit MorphologyAlterationOre MineralogyTin Resource EstimationExploration Assessment StudiesGeochemistry of the Igneous RocksMajor ElementsTrace ElementsRubidium-Strontium Isotope StudyDiscussionGeophysical SurveysMagnetic SurveyVLF-EM SurveyRadiometric SurveySoil Geochemical SurveyPan Concentrate SurveyConclusions Tin and tungsten are critical and strategic minerals to the United States. The basis for such a designation exists in the historic and current
Thiocyanic Acid in Ion Exchange & Solvent Extraction of Metals
Table of ContentsMetal Thiocyanate SystemsThiocyanic Acid and ThiocyanatesDiscussions Metal separations and metal recoveries by ion exchange and solvent extraction of their thiocyanate complexes are widely practiced in analytical chemistry as well as in some industries. Consequently, a critical review of the chemistry of thiocyanic acid and thiocyanates is presented in the second part with the aim of providing a clearer
Smelting & Refining Terms and Conditions – Typical Example
Table of ContentsMetal PaymentTreatment DeductionPenalties One of the most frequently asked questions is: “Where is copper (price and usage) going?” I will not attempt to forecast either the future price of copper or the future growth of the copper industry; rather I would like to discuss the current trends experienced in the smelting and refining terms and conditions for sales
Slurry Handling
Table of ContentsCascadesReceiving SumpsDrop Boxes The need to move large tonnages of slurry has grown as mines have become larger. As existing tailing depositories are filled up, new mines developed, or environmental requirements dictate, it becomes necessary to transport tailing particularly over longer distances. There are two basic types of slurry transport systems, packed flow and slack flow. Packed flow
Platinum & Palladium Ore Flotation Pilot Plant
Table of ContentsBench-Scale Flotation TestsRougher FlotationCleaning of Rougher ConcentratesPilot Mill OperationMetallurgical ResultsExamination of Rougher Circuit ProductsCleaning of Rougher Concentrates We have been conducting research on methods for beneficiating platinum-palladium ores from the Stillwater Complex, Montana. The Stillwater Complex contains the only known major deposits of platinum-palladium ores in the 48 contiguous States. Exploration by Johns-Manville Corp. (Manville Corp.) has resulted
Gold Mill Tailings Restoration
Environmental Setting A basic understanding of the climatic characteristics, geology, surface and groundwater hydrology conditions together with the physical and chemical characteristics of selected mill tailings deposits will aid in understanding the environmental problems associated with tailings disposal and restoration. The Black Hills region is in the mid-latitudes which have a prevailing westernly airflow. The weather in this region is
Tower Mill Grinding of Molybdenite Concentrate
Table of ContentsTower Mill CircuitTest ProceduresTower Mill On-Line OperationTower Mill EfficiencyGrinding Kinetics Modeling A Tower mill consists of a vertical grinding vessel provided with a central shaft screw-shaped impeller. The screw impeller rotates in such a way as to move the grinding media upward through the central portion of the grinding compartment and downward through the outer portion. Grinding media
Slurry Thickening & Dewatering
Dewatering refuse tailings with a belt filter press has not been widely accepted by the Coal Industry. Part of the problem lies with the highly variable characteristics of the refuse solids themselves. The belt filter press, like other dewatering devices, is highly dependent on these dewatering characteristics. The purpose of this study was to examine the feasibility of using a
How to Recycle Tungsten Carbide
Tungsten carbide (WC) is chemically a binary compound of tungsten and carbon in the stoichiometric ratio of 93.87% tungsten and 6.13% carbon. However, industrially the term usually implies cemented tungsten carbides (CWC); a sintered powdered metallurgical product consisting of very fine grains of pure tungsten carbide bound or cemented together in a cobalt matrix. The size of the tungsten carbide
Precipitation of Mercury in Cyanide Gold Leaching
Table of ContentsMaterial Equipment and Operating ProcedureResults and DiscussionEffect of Process Variables on Mercury ExtractionCyanide ConcentrationLeaching TimeSolution pHTemperatureParticle SizeMercury Removal by Sulfide PrecipitationMercury Precipitation from Leach SlurryMercury Precipitation Prior to the Carbon-In-Pulp CircuitMercury Precipitation in a Laboratory Grinding Circuit Numerous low-grade gold-silver ore deposits are being mined and milled throughout the Western United States. In addition to gold and silver,
Potash Recovery by Solar Evaporation & Flotation
Table of ContentsLaboratory-Scale ResearchEvaporation ExperimentsDescription of Process and Waste BrinesLaboratory Evaporation ProcedureEvaporation Results and DiscussionBeneficiation of Crude EvaporitesGrinding StudiesFlotation of Chloride EvaporitesFlotation of Sulfate-Chloride EvaporitesHigh-Sulfate EvaporitesLow-Sulfate EvaporitesKainite-Bearing EvaporitesSolar Evaporation-Flotation EvaluationSolar EvaporationBrine AnalysisPond DesignSolar Evaporation ResultsPRU Design and OperationEvaporite PreparationSchoenite FlotationSylvite FlotationSylvite Concentrate LeachingProduct Debrining and Brine RecycleOperationExperimental ResultsMaterial Balance and Economic EvaluationSummary and ConclusionsAppendix.-Economic EvaluationCapital CostsOperating CostsEconomic Evaluation Over 80
Oxygen Self Rescuers
Table of ContentsDescription of an Oxygen Self RescuerNiosh-ApprovedCSE AU-9AlDraeger OXY-SR 60BMSA 60-Min SCSROcenco EBA 6.5PASS 700U.S.D. SCEBA-60ForeignAuer SSR-90AZG-40Draeger OXY-SR 30Draeger OXY-SR 45Fenzy Spiral IIWC-7Bureau Of Mines-Developed PrototypesLockheed PBA (Personal Breathing Apparatus)MSA 10-Min PBAMSA 10/60 Oxygen Self-RescuerWestinghouse PBATest Apparatus and Experimental ProcedureResults and DiscussionCSE AU-9AlDraeger Oxy-SR 60BMSA 60-MIN SCSROcenco Eba 6.5PASS 700U.S.D. SCEBA-60AUER SSR-90AZG-40DRAEGER OXY-SR 30DRAEGER OXY-SR 45Fenzy Spiral IIWC-7Lockheed PbaMsa 10-Min
On Stream Analysis
Table of ContentsRadiometric TechniquesX-Ray Tube TechniquesNeutron ActivationA Comparison Between Radiometric and X-Ray Tube Techniques An on-stream analyser cannot be considered in isolation from the mineral process where it is to be ultimately installed. Depending upon the requirements of the process, an on-stream analyser can be designed in several ways. If a feasibility study done on the process shows that several
How to Design of a Multi-Variable Grinding Circuit Control System
In this case, the primary grinding stage in a concentrator comprises a rod mill in open circuit and a semi-autogeneous mill in closed, circuit with a hydrocyclone classifier. All the measurements have computer interfaces and all the control circuits have been implemented by the process control computer. The crushed ore feed to the rod mill is measured by a belt-weigher
Nitrogen Gas Molybdenum Flotation from Copper Concentrate
Table of ContentsNitrogen Flotation SystemDepressant ConsumptionMetallurgical ResultsRole of Nitrogen in the Flotation of MolybdeniteFlowsheetCircuit ChemistryNitrogen Testing Mill feed averages 0.7% Cu, primarily as chalcopyrite, and 0.024% Mo. The copper concentrator produces 1050 mt/day of bulk Cu-Mo concentrate averaging 27% Cu and 0.6% Mo. Molybdenum plant feed is thickened to 62% solids and stored in two 150 cubic meter tanks. Two
How to Recover Potash from Carnallite
Table of ContentsSample DescriptionContinuous Flotation Unit Design and OperationDesign For Insoluble-Slimes FlotationDesign For Direct FlotationOperationSampling and Data AnalysisExperimental ResultsMaterial Balance and Economic EvaluationSummary and ConclusionsAppendix—Economic EvaluationCapital CostsOperating Costs The Bureau of Mines conducted research on techniques for recovering potash values from high-insoluble-slimes-bearing domestic carnallite ores. In the first phase of the study, two techniques were devised: (1) a method where the
Electro-depositing PGM Platinum Group Metal Coatings
Table of ContentsHistorical PerspectiveScope of ReportElectrolyte PreparationDrying and Fusing of SaltsPlatinum-Group Metal AdditionRole of OxygenElectrodepositionSubstrate Surface PreparationMolybdenum-Base AlloysIron-Base AlloysElectroplatingPlatinumRhodiumPlatinum-Rhodium AlloysPalladiumIridium and RutheniumSubstrate EffectsIncomplete PreparationMicrostructureSummary The Bureau of Mines has evaluated the substitution of platinum-group metal coatings for bulk platinum-group metal objects as a means of reducing the consumption of the platinum-group metals. The Bureau has conducted several studies of the
Effect Particle Size on Leaching of Sulphide Minerals
Commercial leaching of sulphide ores by microorganisms is used in numerous oxidation situations as a scavenger process for treating low grade ores and very dilute metal waste streams at comparatively low capital and operating costs compared with conventional hydrometallurgical processes. Studies using synthetic mixtures to give pre-determined surface areas have also revealed that the size distribution of the sample is
Gold & Uranium Pregnant Solution Clarification
Table of ContentsExperimentalFiltrationDiscussion of ResultsFiltrationPregnant Solution Clarification Before precipitation of gold can be commenced the relatively high suspended solids content (on average 350 mg/L) of the gold bearing rotary filtrate has to be reduced below 5 mg/L. On most gold mines to which AAC provides technical services a final polishing step to achieve the required clarity takes place in Stellar