Blogs
Stone Cutting and Polishing
Table of ContentsCutting Rocks in the Quarry (2)Cutting and Finishing Stone in MillsLimestone (4)Marble (2)Sandstone (2)Granite (5)Slate (3)Cutting and Polishing Gems and Semiprecious StonesMaterials Used and Their Products (10) (16)Hardness of Ornamental StonesPrincipal OperationsSawingTypes of SawsSawing EquipmentGrindingLappingSandingPolishingPolishing BuffsPolishing AgentsPolishing OperationsDrillingCutting CabochonsCutting Faceted StonesCutting JadeCutting Quartz CrystalsTumblingSpecial Cutting ProcessesPrecautionary MeasuresLapidary Equipment and Supplies The mining and fabrication of structural and ornamental
Heavy Liquid Testing Procedure
Table of ContentsHeavy Liquid SeparationDescription of MaterialsOreHeavy LiquidApparatusProceduresExperimentalAnalyticalData EvaluationA Study of the Influence of Particle Size, Feed Density, and Feed PressureEffect of Particle SizeEffect of Pulp DensityEffect of Feed PressureInfluence of Feed Grade and PressureEffect of Feed GradeEffect of Feed PressureSelected Cyclone Parameters and Feed DensityEffect of Apex Opening SizeEffect of Vortex Finder SizeEffect of Pulp DensityMultistage Cyclone SystemsResults of
Fluorspar Beneficiation Process Plant
Table of ContentsThe Fluorspar Beneficiation ProblemA Fluorspar Flotation Process FlowsheetCrushing Fluorspar OreGrinding CircuitPulp ConditioningFluorspar FlotationThickening and FilteringDrying and StorageProduction of Acid Grade FluorsparThe Acid Grade Fluorspar ProblemThe Acid Grade Fluorspar FlowsheetCrushing CircuitGrinding CircuitConditioning TankFluorspar FlotationThickening and FilteringDrying and StorageDifficult Flotation of some Flourspar OreThe Difficult Metallurgy ProblemThe More Complex Treatment FlowsheetFATTY ACIDS IN FLUORSPAR FLOTATIONDesign Study for 125-Ton Fluorspar MillTin Process FlowsheetConcentrator SiteProcess Plant DesignFluorite
Refine Zinc from Iron Impurity
Table of ContentsPresent Practice for Removing Small Amounts of Iron from ZincMaterials TestedSegregation and Filtration StudiesSegregation TestsDescription of Small-Scale FilterExperimental Filtration ProcedureResults of Small-Scale Filtration TestsLarge-Scale Filtration TestCentrifugation StudiesDescription and Operation of the CentrifugeExperimental ProcedureResults of Centrifugation TestsRemoval of Residual Aluminum and Recovery of Zinc from Residues A process was developed in which iron-contaminated zinc was refined to readily acceptable
How to Recover Lead & Copper from Blast Furnace Matte
Table of ContentsBrine Leaching DevelopmentsMaterials TestedPreliminary Experiments and ResultsCyclic Leach of Matte AWater Leach SeriesBrine Leach SeriesCyclic Leach of Matte BWater Leach SeriesBrine Leach SeriesFinal Cyclic Leach of Matte BWater Leach SeriesBrine Leach SeriesDiscussion This research has shown that & solid waste byproduct from secondary lead smelters can be successfully processed to recover copper and lead that is lost during
Electrorefining Vanadium Scrap
Table of ContentsDescription of Equipment and ProcedureElectrolytic CellMaterialsOperating ProcedureExperimental InvestigationHeavy ScrapRefiningQuality of ProductLight ScrapRefiningQuality of ProductGranular ScrapRefiningQuality of ProductDiscussion A molten-salt electrorefining process was developed which provides a practical way for reclaiming vanadium from scrap generated in the processing of ductile vanadium into bar, sheet, wire, and other shapes. Refining produced extremely ductile vanadium with a purity range of 99.93
Ball Mill Pulverizing
Table of ContentsExperimental Test SystemTest ProceduresTest ResultsInfluence of Initial Moisture Content of LigniteIn-The-Mill DryingLignite SourceComparison of Results to Pulverization in a Test Hammermill As in a pilot-plant-scale hammermill, the effect of moisture content in the pulverization of lignite in a similar size ball mill was observed to be a highly significant factor with respect to power required and in pulverization
Fluorine Determination Method
Table of ContentsSpadns-Zirconium MethodAshing with a Fixative AgentSodium CarbonateCalcium OxideDistillation with Phosphoric and Sulfuric AcidsFluorine and Phosphorus in Float and Sink FractionsFluorine Determinations of Coals Coal normally contains trace amounts of fluorine ranging up to about 0.02 percent. These small quantities of fluorine generally are volatilized when coal is burned in boiler furnaces. but they may be a transient factor
Vacuum Arc Melting
Table of ContentsTheoretical Pattern of Heat Transfer from Ingot to Cooling WaterExperimental Procedure and ResultsNonconsumable Electrode Arc Melting StudiesConsumable Electrode Arc Melting StudiesExperiments with the 2-5/16-Inch-Diameter CrucibleExperiments with the 8-Inch-Diameter CrucibleEffect of Narrow Annular Spacing for Water JacketsDiscussionCrucible Wall ThicknessWater Jacket DimensionsConclusions During the past decade, several novel melting and casting techniques including vacuum arc melting, skull casting, Hopkins’ Process
Mining by Nuclear Explosives Fracturing
Table of ContentsHistory and Commercial Examples of In-Situ Copper Leaching MethodsCopper DepositsChemistry of Leaching CopperThe Effect of Bacteria on the Solubility of Copper Minerals and the Reaction of Bacteria to RadioactivityMechanics of LeachingNuclear ExplosivesPublic LiabilitySafety ProblemsAir BlastGround ShockRadioactivityRadiation Hazards to Off-Site EnvironmentRadiation Hazards to On-Site PersonnelContamination of CopperApplication of In-Situ Leaching to Nuclear Fractured DepositEconomics of Nuclear Fracturing and In-Situ
Gold Distribution & Variability in Drill Core
Table of ContentsPurpose of WorkMine Location, Geology, and ProductionExperimental DataHole DrillingCore Sampling and AssayingStatistical AnalysisFrequency DistributionsSources of VariabilityEstimation of Metal GradeAppraisal of Assaying The extreme variability in gold mineralization in drill core is revealed through the detailed sampling experiment. This variability is that naturally present on the smallest scale that can be found by fire assay. With samples of substantially
Electrowinning Rare Earth Elements
Table of ContentsCell Design and OperationElectrowinning NeodymiumElectrowinning PraseodymiumElectrowinning Didymium Electrowinning Rare Earth Elements like Neodymium, praseodymium, and didymium, were (obviously) electrowon from their oxides dissolved in fluoride melts. The use of a thermal gradient cell resulted in recovery of nodules of well-coalesced metal with a purity of 99.9 percent. Current efficiencies of up to 83 percent were obtained. Shallow immersion
Electrorefining Vanadium
Table of ContentsElectrolytic CellOperationPreliminary InvestigationsNaCl-VCl2 ElectrolyteLiCl-NaCl-VCl2 ElectrolyteBaCl2-KCl-NaCl-VCl2 and KCl-LiCl-VCl2 ElectrolytesLaboratory-Scale Production TestsElectrorefining in a KCl-LiCl-VCl2 ElectrolyteElectrorefining in a CaCl3-NaCl-VCl2 Electrolyte A molten salt, inert-atmosphere electrorefining process was developed for producing ductile vanadium from commercial vanadium. Five different chloride electrolytes were utilized. The chief impurity elements in the commercial vanadium were aluminum, iron, molybdenum, nitrogen, and silicon totaling 8 percent. Refining
Conveyor Belt Fire Hazard
Table of ContentsGallery TestsVentilating ConditionsIgnition SourcesPreliminary TestsMine TestsFire FightingResultsBelt IgnitionFlame PropagationExtinguishing Conveyor Belt Fires This investigation showed that neoprene, polyvinyl chloride, and rubber belts ignite readily when subjected to an impinging flame. Although pre-heating of the belt is not necessary for ignition, preheating does increase the probability of developing a self-sustaining flame after ignition. The time and total quantity of
Electric Smelting Lead Zinc
Table of ContentsTheoretical ConsiderationsSintering ExperimentsEquipment and MaterialsProcedureResultsDiscussionSmelting and Refining InvestigationsSmelting Equipment System and MaterialsProcedureResults of Water-Cooled, Condenser TestsResults of Molten-Metal, Splash-Condenser TestsSpecial Smelting InvestigationConventional Zinc Oxide SmeltingProcedure and MaterialsResultsEffect of Iron (Zinc Ferrite) on Recovery of Zinc MetalProcedure and MaterialsResultsEffect of Lead Oxide on Recovery of Zinc MetalProcedure and MaterialsResultsCombined Effects of Lead Oxide and Zinc Ferrite on the Recovery
Mine Sampling Assays
Table of ContentsStatistical Techniques used for the InvestigationMean-Square-Successive-Difference TestCorrelationSource of Assay Data TestedClimax Molybdenum DepositMean-Square-Successive-Difference TestsCorrelationCebolla Greek Titaniferous Iron DepositMean-Square-Successive-Difference TestsCorrelationSan Manuel Copper DepositMean-Square-Successive-Difference TestsCorrelationDiamond-drill holesChurn-drill holesPiedra Hueca Copper DepositMean-Square-Successive-Difference TestsCorrelationButte Copper DepositMean-Square-Successive-Difference TestsCorrelation A continuing problem in mine evaluation, planning, operations, and production scheduling is the necessity of assigning some value for the grade of mineralization which occurs in
Recover Hydrofluoric Acid from Fluosilicic Acid Waste
Table of ContentsExperimental Procedures and ResultsDirect Hydrolysis of H2SiF6Hydrolysis of Lime-Neutralized H2SiF6 This report describes a preliminary investigation of methods for recovering hydrofluoric acid (HF) from waste byproduct fluosilicic acid (H2SiF6). Fluosilicic acid is generated by plants processing phosphate rock in the manufacture of fertilizer; most phosphate rock contains 3 to 5 percent fluorine in the form of the mineral
Calcium Vanadate Precipitation and Processing
Table of ContentsMaterials, Equipment, and ProcedurePrecipitation of Calcium Vanadate from Synthetic SolutionsPrecipitation With Calcium ChlorideEffect of pH on Precipitate CompositionEffect of pH and the Quantity of Calcium on Precipitate Composition and Vanadium RecoveryEffect of Vanadium Concentration on Completeness of PrecipitationPrecipitation With Milk of LimePrecipitation from Autoclave Leach SolutionProcessing Calcium VanadateDicalcium Vanadate Recovered From Synthetic SolutionLeaching in HCl and H2SO4 SolutionsLeaching
Iridium Electrodeposition
Table of ContentsElectrolysis of Fused Sodium Cyanide ElectrolytesCoatings of Pure IridiumAlloy Coatings of Iridium With Other Platinum-Group MetalsElectrolysis of Aqueous ElectrolytesEvaluation Adherent, coherent electro-deposits of iridium 15 mils thick and alloys of iridium 4 mils thick were formed in argon atmosphere from fused cyanide electrolytes. The use of pure iridium to prevent oxidation appears limited to temperatures under 1,000° C
Magnetic Separation of Pyrite
Table of ContentsPrevious Studies of Magnetic Separation of Pyrite from CoalsPublished WorkUnpublished Studies by the Bureau of MinesPresent Studies of Magnetic Separation of Pyrite from CoalsIntroductionSize Distribution of Pyrite Particles in CoalsMagnetic Susceptibilities of United States CoalsMagnetic Susceptibilities of Some Compounds of IronEnhancement of Magnetism of PyriteEffect of Storage on Sulfur FormsEffect of Pulverization of Coal and PyriteMagnetic Susceptibility and
Smelting low Pyrite Copper Concentrate
Table of ContentsRaw MaterialsEquipment and ProcedureResultsNonpyritic Smelting With Normal SulfurNonpyritic Smelting With Excess SulfurNonpyritic Smelting With Deficient SulfurDiscussion of ResultsGypsum as a Pyrite Substitute A laboratory smelting study was conducted on a copper ore containing chalcocite and native copper to test the technical feasibility of non-pyritic smelting (low pyrite). The results of this investigation led to the following conclusions, based
Columbium Alloys
Table of ContentsMicrostructureX-Ray DiffractionHardnessFabricationRecrystallizationStrengthOxidation ResistanceDiscussion of ResultsSummary As a continuing endeavor, the Bureau of Mines is developing columbium and tantalum alloys for high-temperature applications. This investigation was undertaken to improve the high-temperature properties displayed by the more common columbium alloys that are commercially available. In a previous investigation beneficial improvements were realized by alloying columbium with elements such as hafnium,
Columbium Tantalum Flotation
Table of ContentsContact-Angle StudiesEquipment, Materials, and Test ProcedureContact-Angle ResultsMicroflotationEquipment, Materials, and Test ProcedureMicroflotation ResultsAnionic ReagentsCationic ReagentsBatch Flotation StudiesOka Pyrochlore OreDark Star Ore The purpose of this investigation was to determine the flotation characteristics of important columbium / tantalum ore minerals as a guide for the practical concentration of low-grade columbium ores. Placer deposits amenable to gravity concentration have been the
How to Purify & Concentrate a Manganese Leach Solution
Table of ContentsExperimentPreparation of Leach LiquorTest Equipment and ProcedureResultsKinetic AnalysisKinetic Analysis of Ammonium-Manganese Sulfate Precipitation A temperature of 250° to 260° C was found to be satisfactory for simultaneous removal of iron and manganese from the pregnant leach liquor resulting from leaching of low-grade manganese ore. A holding time of about 15 minutes at this temperature was sufficient for maximum