Blogs
Photoelectric Charging & Electrostatic Separation
Table of ContentsPhotoconductivity Versus Photoemission of ElectronsUltraviolet Light Absorption in AirPhotoemission Effects of Conductive MineralsPhotoemission from Dust-Size ParticlesCharge Required for Dust Separation Electrostatic separation is used when froth flotation fails, such as with oxidized ores, or where there are similarities in response with magnetic and gravitational methods, or when the use of water is to be avoided. Theoretically, for fine-size
Effect of Preheating Iron Ore Pellets
Table of ContentsRaw MaterialsProcedure and EquipmentPelletizingExperimental WorkEquipmentResultsOxidation of MagnetiteSinteringEffect of Preheating Upon MetallizationEffect of Preheating Upon Pellet Properties The production of pre-reduced iron ore pellets involves the expenditure of considerable capital and energy. Both prereduced and oxide pellets can be produced in similar equipment by using reducing and oxidizing processes, respectively. However, the throughput for a 5-m-ID by 50-m-long kiln
Electrodynamic Separator
Table of ContentsSample TestedApparatus and Procedures Used Several years ago, the Bureau of Mines initiated a program to develop effective methods for reclaiming and recycling metal and mineral values contained in urban solid waste. The Bureau’s initial work at its College Park (Md.) Metallurgy Research Center dealt with establishing reliable methods for sampling and characterizing the residues left from the
Applied Mining Geology
The geologic notes are taken as soon as possible after the ground is broken so that any mistake in the mining may be corrected at once, or any particularly advantageous procedure may be suggested before any useless work is done. Taking the notes underground is a comparatively simple matter, but a few necessary precautions may be pointed out. The essential
Small Scale Metal Recycling Plant & Equipment
Table of ContentsTechnical ConsiderationsFlowsheetPilot Plant PerformanceProduct UtilizationProcess EconomicsFuture Plans Of the 220 million tons of refuse collected annually in the United States, it is estimated that about 30 million tons are incinerated, generating about 7 million tons of residues. In previous work, the Bureau of Mines developed a continuous mechanical process capable of converting 85 percent of municipal incinerator residues
How to Remove Pyrite from Coal
Table of ContentsDry-Separation ProcessCentrifugal SeparationElectrostatic SeparationGrindability of Pyrite and Coal-An Aid in SeparationCombined Centrifugal-Electrostatic Separation In recent years, coal research has been directed toward environmental problems of the electric power generation industry. A major problem of coal-burning power-plants is reducing the air pollutants in stack gases. In most of these plants, the chief pollutant is SO2, which results from the
Precious Metals – World’s Top 10
Ever wondered why people keep their gold pieces in safes? And why your family silverware is always so well protected? Well, that’s obviously because gold and silver are two precious metals. That you already know… But what about other metals? There are other substances equally precious, even more, precious than gold, that you must get to know better. So here’s a
How to Separate Copper from Scrap by Melting
Table of ContentsAcknowledgmentsLaboratory EvaluationExperimental ProcedureSweating With Other Predip TreatmentsElectronic Component SweatingDiscussion and Concluding RemarksCost EstimateDescription of ProcessesEstimating MethodCapital CostsOperating CostsEvaluation, Results, Discussion, and Conclusions The secondary metals industry has been a major segment of the domestic economy for years. Many secondary commodities (heavy melting steel and lead storage batteries are familiar examples) have become so well established and recycled so
Copper Smelting
Table of ContentsCopper Smelting ProcessHeat Balance Using Pure Oxygen Versus AirCopper Smelting Furnace Construction and Refractories UsedTest Procedure and Discussion of ResultsSlag Composition, Losses, and Forms of CopperAnalytical TestsInduction Furnace TestsFlotation Tests Throughout this century the major production of copper (as it relates to Copper Smelting) and most other nonferrous metals has been through pyrometallurgical methods, treating sulfide ores by
Permanent Magnets
Table of ContentsAlloy PreparationPowder PreparationAlignment and CompactionSintering ProcedureMagnetic MeasurementsResults and DiscussionOptimum CompositionEffects of CompositionEffects of Sintering TemperatureEffects of Grinding The magnetic properties of rare earth-cobalt intermetallic compounds have been studied by various investigators. It was not until Strnat and Hoffer investigated single crystals of YCo5 and reported an extremely high magnetocrystalline anisotropy that systematic studies of the magnetic properties of
Kaolin Attrition Grinding
Table of ContentsAttrition GrinderBatch Grinding TestsContinuous Open-Circuit StudiesSingle-Stage GrindingModified Single-Stage GrindingMultiple-Stage GrindingContinuous Closed-Circuit GrindingTest ProcedureCentrifuge Classification TestsClosed-Circuit Grinding Fine grinding research has resulted in the development of an attrition grinding process: that has been successfully used for ultrafine grinding of various solid materials. The process was initially developed and patented by the Bureau at the Tuscaloosa Metallurgy Research Laboratory to
How to Extract Silver from Refractory Ores
The recovery of silver from ores by hydrometallurgical techniques changed considerably toward the end of the 19th and in the early part of the 20th century. Metallurgical techniques, such as amalgamation, chloride roasting followed by amalgamation, hyposulphite leaching, and the Patio process (amalgamation of silver formed by the reaction of silver minerals with sodium chloride and copper sulfate) have been
Copper Cement Oxidation
Table of ContentsOxidation Roasting ResultsOxygen Concentration EffectTemperature EffectRetention Time EffectCyclic Roasting Cement copper production has been increasing steadily because more mine waste from open pit mining is being leached and the copper recovered by cementation on scrap iron. Current estimates indicate that about 13.1 percent of the Nation’s production of primary copper is from this source. Cement copper is usually
How Plastic is Recycled
Table of ContentsAir ClassificationLiquid MediaScreening and Electrostatic SeparationExperimental ResultsLocal Plastics CollectionRecycling Center ProductPilot Plant ConcentratesWire Insulation WastesPotential Utilization TechniquesRefabricationEnergy and Chemical Recovery This is the age of plastics. Plastics are rapidly replacing metal, glass, and wood in parts of appliances, automobiles, prepackaged consumer goods, pipe, beverage containers, and furniture. The total sales of U.S. plastic for 1972, as shown in
Chalcopyrite Sulfuric Acid Leaching Kinetics
Table of ContentsChalcopyriteSample PreparationNeutron IrradiationLaboratory ProceduresApparatusExperimental ProceduresTreatment of DataResults and DiscussionEffect of pHSurface AreaPreferential LeachingEffect of Ferrous and Cupric Ion Additions at Room TemperatureEffect of Oxidants at Ambient TemperatureEffect of Oxidants at Elevated TemperaturesDissolution of Chalcocite and Covellite in Sulfuric Acid MediaEffect of Metallic Additions on the Dissolution Mechanisms of ChalcopyriteTheoretical Considerations Renewed interest in hydrometallurgical recovery of copper from
How to Steam Cure Bricks
Table of ContentsBrick Specifications and Manufacturing MethodsSolid Mineral WastesLaboratory Test ProceduresPreliminary TestingTesting of Other WastesEconomics of Brick Production and Marketing In the processing of numerous types of minerals to recover their values, enormous tonnages of gangue materials are produced and discarded to storage areas near the processing plants. In this country, primary copper producers alone produce 125 million tons of
How to Clean Titanium Alloy Scrap
Table of ContentsCharacteristics of Scrap Titanium Alloy ChipsExploratory TestsTungsten Carbide AdditionsHydride-Crush-DehydrideSolvent CleaningDetergent CleaningAnodic Solution TestsChemical Solutions TestsProcessing Unit Recycled titanium scrap is mixed with titanium sponge for ingot production and, therefore, plays an important role in the production of mill products. Clean and segregated scrap is recycled fay producers that regard their scrap-recovery procedures as proprietary. Unless a rigorous procedure
How to Recover Metals from Zinc Smelter Residue
Table of ContentsPyrometallurgyGranulationMatte SmeltingProceduresRecovery of Copper from Iron Derived from Matte SmeltingQuiescent, Slow CoolingExtraction of Copper with Metallic LeadExtraction of Sulfur and CopperExtraction of Copper with Sodium Sulfate Primary smelting of zinc in horizontal retort distillation furnaces leaves a residue consisting of the following: unburned carbon, iron as metal shot and stringers, copper inclusions in the iron as metal and
Use of Cryogens Liquid Nitrogen to Recycle Scrap Metals
Table of ContentsMaterials TestedEquipment UsedChilling ChamberCrushing ApparatusWater Elutriation and ScreeningImmersion Chilling Experimental ResultsChilling ProceduresTreatment of Insulated WiresEstimate of CryogenTreatment of Mixed Nonferrous Metal ConcentratesChilling of Miscellaneous MaterialsIndirect Chilling Scrap such as insulated copper wire, small motors, automobile tires, and nonferrous concentrates from automobile shredders contains materials that become brittle at low temperatures and other materials that remain malleable. Crushing of
Mica Beneficiation
Table of ContentsPart 1.—Mica Process DevelopmentDescription of OresMica Analysis MethodsFlotation MethodsAcid Cationic Flotation MethodAlkaline Anionic-Cationic Flotation MethodContinuous Flotation Pilot PlantPegmatite OresAcid Cationic MethodAlkaline Anionic-Cationic MethodCombination of Acid Cationic and Alkaline Anionic-Cationic MethodsMicaceous Schist OresAcid Cationic MethodAlkaline Anionic-Cationic MethodSummaryPart 2.—Industrial Mica ProductionMiningMica Recovery ProcessesRolls and TrommelsHumphreys SpiralsFlotationGrindingDry GrindingWet GrindingProductionUses In recent years, more than 99 percent of the domestic mica produced
Chlorine Leaching Copper
Table of ContentsMaterial Equipment and ProcedureExperimental ResultsLeaching Copper Sulfide MineralsDiscussion of ResultsCovelliteChalcopyriteChalcociteBorniteLeaching PyriteEffect of pH Variations The high reactivity of chlorine as an oxidizing agent in leaching ore has long been recognized, but chlorine has not been extensively used because of high costs and because of the corrosiveness of acid chlorine solutions. As early as 1848, the use of aqueous
Copper Cementation on Iron
Table of ContentsCementation TheoryExperimental Procedure and ApparatusResults and Discussion Cementation of copper onto iron is a historically old process for recovery of copper from leach solutions. Although about 13 percent of the Nation’s primary copper production is from cementation, this process remains more of an art than a science. The literature on cementation is extensive, but a thorough review shows
Rare Earth & Hydrogen Oxygen Fuel Cell
Table of ContentsCatalyst PreparationActivity MeasurementsGas ChromatographyResults and Discussion The activity of rare-earth compounds for catalysis of the hydrogen-oxygen reaction is of interest because of their possible use for electrocatalysis of the cathode reaction of a hydrogen-oxygen fuel cell. Although platinum metal has been widely used as a fuel cell catalyst, its high price and relatively limited supply prohibit its use
Tailings Pond Seepage
Table of ContentsGeneral GeologyVan Stone Field InvestigationSampling, Instrumentation, and Field ObservationsConsolidation and Grain SizeWater MovementField Resistivity TestsLaboratory DataEnvironmental Field and Laboratory InvestigationStream Sediment AnalysisResults and Conclusions of Sediment AnalysisWater Quality of Receiving StreamFinite-Element AnalysisEnvironmental Design Criteria This report is a sequel to earlier Bureau of Mines investigations which indicated the need for a seepage environmental research investigation relative to the