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How Particle Size Affects Flotation
There is a marked particle size effect on both R and K. Table V gives an example of increasingly finer grinds in flotation with a different sulfide ore blend. Within the times of grind indicated, there is a tendency for both the over-all R and K values to increase with finer grind [see also Table III of reference]. This trend
Grindability of Various Ores
During the last few years, one of the great problems in the milling of all ores has been that of grinding. This subject involves not merely the cost of the operation, but also the selection of the proper degree and character of grinding to yield the best metallurgical results on the given ore. Considering the diversity of machinery, one is
How to Track & Control Metallurgy using Charts & Graphs
Table of ContentsGraphic PresentationMining ControlWall-ChartsDisplay of Large ChartsPeriodic ReportsScreen Analysis DiagramsHeading—Tailing/Heading The graphic methods and records described in this article have been developed, with satisfactory results, for the use of executives of the Chino Copper Co., in Hurley,. N. Mex. Particular attention is directed to the use of large wall-charts, the quick reference display of large charts, the scale notation of
Fine Gold Recovery & Refining
Table of ContentsHow to Remove Copper from Fine GoldAcid Treatment of Fine GoldPreliminary TestsTreatment of Roasted Slime with Sulphuric & Nitric AcidsTreatment of Raw Slime with Hydrochloric & Sulphuric AcidsTreatment of Roasted Slime with Hydrochloric AcidCombination: Acid – Roast – AcidTreatment with Ferric SulphateSmelting in Furnaces Lined with Carbon-Free RefractoriesFusion of Gold Slime with Salt CakeConclusion How to Remove Copper from Fine
Precious Metal Refinery Procedures
Table of ContentsRecovery of Metals from Mattes and SlagsBy Products of Gold RefinerySlagsMattesLead Bath Treatment of MatteProgrammeSummaryReduction of Mattes to MetalsReduction of Matte to Base BullionCupellation of Base BullionRefractory Lining for Cupel TestMixing:Tamping:Treatment of old Furnace LinersCupellationRecovery from Cupellation OxidesSummary and Flow Sheet Recovery of Metals from Mattes and Slags Long ago, mattes and slags, which were the end products of the
Gold Refinery Procedures
Table of ContentsPast Gold Refinery PracticeClean-upRoastingSmeltingBarring FurnaceGranulation & Sulphuring of BullionBest Gold Refining MethodsSilver & Gold Smelting PracticeMatte SmeltingTreatment Times and QuantitiesAmalgamationFlotation StrakesRoasted Concentrate StrakesRetorting of Amalgam Before processing by the gold refinery, gold can be extracted from ore by the following series of operations: Coarse crushing; Fine grinding; Straking for free gold; Flotation; Concentrate roasting; Straking for free, gold; Cyanidation of
Fire Assaying History
The beginning history of fire assaying can be traced to the finds in Troy II (about 2600 B.C.) and in the Cappadocian Tablets (2250-1950 B.C.). These finds prove that very pure silver was made in the twenty-fifth century B.C. From this evidence we must conclude that the cupellation process, and therefore fire assaying, was invented in Asia Minor in the
Grinding Media Wear Rate Calculation in Ball Mill
Table of ContentsData on Ball ChargesBall Mill Ball Wear ProjectionRecapitulation of Ball Wear FormulasPractical Application of Theoretical Conclusions In the previous discussion the fact was established that the work done by a ball when it strikes at the end of its parabolic path is proportional to its weight and velocity; then, since the velocity may be considered as constant for all
Assaying
Table of ContentsFire AssayingAssay Flux ReagentsSelection of Flux ComponentsSample PreparationEquipment and MaterialsWeighing the ComponentsSelection of Sample WeightThe Crucible FusionTheory of the Crucible FusionFusionFusion of Chromite Bearing Samples using an Auxiliary FluxPreliminary FusionRefusionsFusion of Used CupelsCupellationScorificationMethods of AnalysisDetermination of Gold by Fire Assay and Atomic AbsorptionProcedure for GoldPreparation of Standards and the Analytical CurveDetermination of Gold by Fire Assay and Neutron-Activation
Ball Mill Grinding Theory – Crushing Motion/Action Inside
Table of ContentsOpen Circuit GrindingClosed Circuit GrindingSingle Stage GrindingTwo Stage GrindingFirst Stage of Ball MillingSecond Stage of Ball MillingLarge VS Small Grinding BallsRelation between Speed of Mill & Size of Balls in MillDeductions from Operating TestsDesign & Regulation of a Fine Crushing PlantMechanics inside a Ball MillAction of Charge at Slow SpeedMotion of Charge at Higher Mill SpeedParabolic Paths of Falling ParticlesApplication to a Definite ProblemBlow Struck by Falling ParticleCycle of
SX EW Capital & Operating Cost of Solvent Extraction & Electrowinning
Table of ContentsPresentation of the DataCapital CostsSolvent ExtractionElectrowinningTotal SX-EW Capital CostsOperating CostsLabor RequirementsReagent ConsumptionKerosene UsageMajor Tankhouse Costs (Table 6)Summary of CostsCase StudyConclusion Solution mining followed by solvent extraction-electrowinning (SX-EW) is one possible way to economically extract copper from ore bodies which cannot otherwise be profitably exploited. Published costs for the unit processes of SX and EW are out of date
Iron Ore Beneficiation Process
During the last ten years great strides have been made, on the Mesabi range, in the practice of beneficiating low grade iron ore material. By beneficiation is meant all methods of removing impurities, and raising the iron content to a point where it can be sold in open market, the principal impurities being silica and moisture. The general processes to
Antique Mining Equipment
The early mining of iron ore in Minnesota was carried on with the most primitive kind of tools. The pioneers used only such equipment as could be packed from Duluth through one hundred miles of forest to the first mines on the Vermilion Range and the operations were carried on with picks, shovels, hand drills and wheelbarrows, the ore being
Types of Welding Process
Table of ContentsComposition of Ship-plate SteelChemical Analysis (Ladle Analysis)Physical PropertiesFusion Welding(a) Carbon-Arc Welding(b) Metal-Arc-WeldingSpot WeldingBare and Covered Welding WireSalvaging Wielding WirePreferable Kind of Covering for Welding WirePreferable Composition for Bare Welding WireComposition of Metal Deposited in WeldPolarityArc Welding AC vs DCDirect Current VS Alternating CurrentPeriodicity for Alternating-Current Arc WeldingBare or Covered ElectrodesAlternating-Current Arc WeldingRelative Speeds of AC & DC Arc WeldingCompare Quality of
Spectroscopic Determination of Lead in Copper
Table of ContentsOutline of MethodApparatusStandardization of ApparatusChecking Routine AnalysisAnalysis of Large SamplesSynthetic SamplesVariations in ConditionsAdvantages and LimitationsAppendicesList of MaterialsMethod of Chemical Analysis for Lead in CopperTest of Joly Balance In a previous article preliminary experiments were described, indicating the possibilities of a quantitative spectroscopic method for the determination of small amounts of lead in copper, which would be accurate and
Type of Melting Furnace
Table of ContentsElectric FurnacesFuel-fired FurnacesTemperature Measurements and Observation of Melting The following may be said to be essential characteristics of a furnace for determining the melting point of refractories: It should be capable of easily reaching a temperature of 1800° C., since most refractories melt below 1800° C.; for those materials melting over 1800° C., special procedure and technique are
Melting Point of Refractory Materials
Table of ContentsMeaning of Melting PointFactors & Conditions Affecting Observed Melting PointChemical CompositionSize of Particles and Shape and Position of BodyTime and Rate of HeatingNature of the SurroundingsConditions in Use Affecting Apparent Melting PointPractical Determination of the Melting PointSampling, Grinding, and MoldingTime and Rate of HeatingType of Furnace and Conditions Existing in Furnace The object of this paper is to discuss the
Manganese Bronze
Developments in engineering during the past decade, particularly as applied to marine construction, mining machinery and other purposes in which corrosion offers a serious problem, have created a large demand for a non-ferrous metal highly resistant to corrosion and at the same time useful in general construction work as a substitute for steel without materially decreasing the factor of safety
Mechanical Properties of Metals
In a recent discussion of Dr. Jeffries’ paper on tungsten, J. C. W. Humfrey, after taking exception to certain of the author’s ideas relative to the cohesion of A and C metal, expresses the opinion that future research is likely to develop a method of preparing tungsten possessing “mechanical properties in line with those of other metals.” The present paper
Effect of Forging on Steel Density
The writer has been unable to find much information relative to tests made to determine the effect of forging on the specific density of steel. The opinion, however, among men engaged in the business, seems to be that forging greatly compresses or consolidates the steel. While such is doubtless the case with spongy or porous steel, the following experiments indicate
Charpy Impact Machine
Using a Charpy Impact Machine, we have done considerable work on notch-bar testing and are farther at sea now than when we started. So far, we have been unable to get the notch-bar test to be consistent with any other known test. Lately, I have been investigating the effect of the position of the notch-bar specimen in a bar. To
Babbitt Bearings
Table of ContentsBrinell Hardness of Babbitt Bearings at Increasing TemperaturesEffect of Compression on the Brinell Hardness of BabbittsRolling of Babbitted Linings by the Mills Micrometer Roller Brinell Hardness of Babbitt Bearings at Increasing Temperatures Brinell tests at progressively increasing temperatures are given for a representative lead-base and a representative tin-base Babbitt Bearings, showing that the former has superior resistance to deformation at the
Zinc Vapor Condensation
Table of ContentsDistillation Products from Reduction of Zinc OreMethod of InvestigationNitrogenHydrogen and HydrocarbonsCarbon Monoxide and DioxideOxygenCondition of ZincConclusions from Preceding ExperimentsPreliminary InvestigationsReduction in Carbon TubeReduction in Graphite RetortExperiment with Blue-powder BriquetsConclusions from Preliminary ExperimentsTesting MethodConclusions from Equilibrium InvestigationConditions of the Zinc in Equilibrium ExperimentsRequisites for Successful Condensation The study of the condensation of zinc from its vapor was undertaken to shed
Zinc Dust in Precipitant in Cyanidiation
Table of ContentsZinc Dust PrecipitationContinuous PrecipitationFilter PressingFineness of Zinc DustEfficiency of PrecipitationZinc Dust VS Zinc ShavingsComposition and Treatment of Precipitate In the cyanide process, gold and silver are dissolved from crushed ore as double alkali-metal cyanides, from which they may be precipitated by such positive metals as sodium (amalgam), aluminum, or zinc, or by electrolysis. Two extreme conditions may be noted. Some works, especially