Blogs
Froth Washing in Mechanical Flotation Machines
Table of ContentsFroth DrainageGangue Rejection Mechanisms In the Froth PhaseEffect of Wash Water Addition LocationRole of Wash Water in Froth Cleaning Floatable and non-floatable particles follow different sequence for transport from the pulp to the froth and from the froth out of the cell. For floatable particles, the principal mechanism is true flotation (i.e. bubble attachment and levitatlon). Non-floatable particles
How to Improve Ball Mill Performance
Table of ContentsBall Mill Breakage EfficiencyBall Mill Circuit Functional Performance Equation Application of value engineering techniques to grinding process modelling led to the identification of two basic functions of the ball mill-classifier circuit. In terms of a specified circuit product size which is used to differentiate between “coarse” or oversize material and “fines” or undersize material, these basic functions are
Organic Flotation Depressant
These depressants are organic mixtures reacted with inorganic salts. They have found application for depression of oxidized pyrite, marcasite and pyrrhotite during the flotation of Cu, Cu-Zn, Cu-Pb-Zn and Pb-Zn ores. Some of these depressants have been adapted for depression of zinc during sequential copper zinc flotation. Depressants from the DS series have been successfully applied at Nanisivik Concentrator and
Ultrasonic Mineral Recovery
The ultrasonic treatment unit consists of an inclined, flat bottomed metal trough, usually made of stainless steel or aluminum, with the ultrasonic transducer attached near the upper end. A typical unit would be 91.5 cm (36 inches) wide and 244 cm (96 inches) long. Figure 1 is a photograph of an ultrasonic treatment unit being water tested. The formation of
Carbon Strip Circuit Control Scale
Table of ContentsFormation of ScaleFactor Affecting Scale DepositionTemperaturePressureChange in pHUse Scale Inhibitiors to Prevent Calcium Carbonate ScaleChelation Solves the Problem Carbon strip circuits present a particularly challenging scale inhibition problem. Many of the factors that tend to promote scaling are present in these systems. For example, carbon strip circuits are run at high temperatures, high pH levels, and require long
Environmental Auditing Procedures in Mining
Table of ContentsScope of WorkHazardous Substance Waste Management Environmental audits can serve many purposes. One way in which an audit may be used is to assess an operating company’s compliance with environmental laws while the mine is in operation. Information derived from an audit of this type can guide management toward making immediate adjustments to correct procedural problems before they
Ultimate Pit Limit Design
Table of ContentsRules of Arc GenerationShell Pattern of A Cone In open pit mine planning, the design of the most profitable ultimate pit limit is a prerequisite to developing a feasible mining sequence. Presently, the design of an ultimate pit is achieved through a computer program in most of the mining companies. 3-D block model is commonly applied to represent
How Temperature Affect Grinding Efficiency
Table of ContentsPlant StudiesLaboratory Studies The effects of temperature on autogenous grinding can be immediately divided into rheological effects and mechanical effects. The rheological effects are a result of the substantial increase in the viscosity of water as the freezing point is approached. The change in apparent slurry viscosity which results from changing temperature is shown in Figure 1. As
Compacted Clay Liners
Soils used to construct compacted permeability barriers such as liners for solid and liquid waste landfills and lagoons must be carefully evaluated and designed to maintain their integrity in preventing seepage of pollutants off site. The practice of using any on-site soil without testing its hydraulic and flexural properties is dangerous. Silts and fine sandy silts, although they may be
Sulfate Ion & Anionic Surfactants
Table of ContentsTheoryCritical Surface TensionSurfactant AdsorptionIon ExchangeClose-Packing EffectsHemimicelle FormationMaterialsCoalsWetting Solution ReagentsExperimental ProcedureExperimental ResultsPure WaterSD2ES Surfactant on Hard-to-Wet CoalSD2ES Surfactant on Easy-To-Wet CoalSurface Tension of SD2ES SolutionsOther Anionic SurfactantsNonionic SurfactantDiscussionComparison of Surfactant Wetting PerformanceEffect of Surfactant Concentration on Wetting by SulfateHard-to-Wet CoalEasy-to-Wet CoalSurfactant Coal-Wetting Performance and Surface TensionConclusions The U.S. Bureau of Mines is investigating surfactants added to water sprays to
Heap Leach Pad Liner: Differential Settlement & Strain Estimate
The maximum settlement (S) of the soil subbase occurs at the center of the wetted soil column. There would be little to no settlement along the dry edges of the column. The total settlement can be estimated by multiplying the percent soluble minerals times the controlling depth, DI. As the liner deflects to fill the void created by the settlement,
Leaching Fluorine from Copper Concentrate
Hydrometallurgical Removal of Fluorine from Copper Concentrates: CVRD Technology Center (SUTEC) has developed and patented an hydrometallurgical process route to remove fluorine from copper concentrates, as a result of an extensive testwork to investigate the effect of mineral acids on fluorite solubilization. The process developed consists of leaching the high fluorine copper concentrates with H2SO4 or HCl under controlled conditions. The
Pressure Leaching of Galena to Recover Lead by Electrowinning
Table of ContentsPressure LeachingPurification of LeachatesLead ElectrowinningPressure LeachingOxygen PressureTemperatureCatalystsTimeFree H2SiF6Purification of Leachates and ElectrowinningLeach Residues As part of the U.S. Bureau of Mines program to improve base metal leach systems, pressure leaching of galena (PbS) concentrates in fluosilicic acid (H2SiF6) solution was investigated. Lead extraction was 93 pct when PbS was pressure leached in H2SiF6 at 95° C with 200-psig
Electric Arc Furnace
Table of ContentsMagnetohydrodynamicsEquation of ContinuityNavier-Stokes EquationEnergy EquationMaxwell’s EquationsEquations of StateBoundary ConditionsSteelmaking The U.S. Bureau of Mines is conducting an ongoing research project to better understand the phenomena involved within electric arcs utilized in electric furnace steelmaking. With a better understanding of the physical and electrical characteristics involved, dynamic or predictive control of electric arc furnaces may be possible. A mathematical
Froth Flotation Bubble Collision
Table of ContentsPhysical ProblemSystem ModelParticle SizeTwo Limiting CasesFactors Affecting Collision EfficiencyAssumptionsMathematical ProblemEquations of MotionNondimensional EquationsBasic ParametersViscous Flow SolutionPotential Flow SolutionInitial ConditionsNumerical SolutionNumerical MethodEquations of Motion in Convenient FormNumerical Initial ConditionsRoot FindingCollision EfficiencyResultsComparison With Other Work Collision efficiencies have been calculated using a two-particle model in a strong force field. The nondimensional equations of motion have been solved numerically, showing the
Electrorefining Calcium Metal Electrowinning
Table of ContentsEquipment and MaterialsExperimental Procedure and ResultsElectrowinningElectrorefiningProposed Electrorefining Cell The U.S. Bureau of Mines developed an alternative electrochemical process for the production of calcium metal. The current industrial practice is costly, complex, and inefficient. The Bureau method involved electrowinning of a calcium-tin alloy followed by electrorefining to produce calcium metal. In the electrowinning cell, CaCl2 was fed to a
Column Flotation Testing Better & Improved Recovery
Table of ContentsFluorsparPotential ByproductsBerylMicaSilica SandFlotationExperimental Materials and EquipmentFlotation ColumnsBubble GeneratorProcedureCrushing and GrindingFluorite Flotation CircuitMica Flotation CircuitSilicate (Beryl) Flotation CircuitZeta Potential Studies ProceduresDiscussion of ResultsFluorite FlotationProcess Economics of Fluorite CircuitBeryl FlotationColumn flotation processes designs and practicesColumn Flotation Parameter Testing We investigated column flotation for recovery of a high-grade fluorite (CaF2) concentrate and byproduct concentrates from the Fish Creek fluorite deposit in
How to Recover Chromite
Table of ContentsDeposit DescriptionsEmma Bell And Seiad Creek, Siskiyou CountyBroken Ladder, Del Norte CountySample Description and Mineral Liberation AnalysisEmma BellSeiad CreekBroken LadderLaboratory Beneficiation StudiesTablingVanningSpiralingReichert Tray ConcentrationLocked-Cycle Table-Vanner ProcedureFlotationGrindingThickeningPilot PlantDesign and OperationResults of Pilot Plant TestsSummary and Conclusions The USBM conducted laboratory research including operating a nominal 100 lb/h pilot plant to demonstrate the recovery and concentration of chromite by gravity
Ground Sluicing Operations
Table of ContentsMorganRavanoBar No. 1OsborneRundleBar No. 2KamloopsWillow CreekCamp BirdBennetHarveyMagnus and Ole Lindquist. Inc. In ground sluicing the gravel is excavated by running water not under pressure. Booming is a variation of ground sluicing in which water is stored in reservoirs and is intermittently discharged in large volumes over short periods to obtain the maximum erosional and transporting effect on the
Sulfide Ore Treatment Gold – Silver – Copper – Cobalt – Zinc Recovery
Table of ContentsDescription of Ore SamplesExperimental Procedures and ResultsRoasting and LeachingExploratory Oxidative Leaching TestsOxygen Pressure LeachingStatistical Variable Screening Test DesignEffects of Leaching VariablesComposition of Leach ResiduePrecious Metal Recovery from Leach ResidueTests Using Individual Core SplitsBase Metal Recovery from Leach LiquorIron-Arsenic Removal by Neutralization and PrecipitationCopper Recovery by Precipitation With Hydrogen SulfideZinc Recovery by Solvent ExtractionCobalt Recovery by Ion Exchange and
Gold Sulphide Ore Oxidation by Alkaline Pressure
Table of ContentsExperimental ProceduresResults and DiscussionProposed Process Flowsheet The U.S. Bureau of Mines developed an alkaline oxidative pretreatment to increase the recovery of gold from refractory sulfide ores containing arsenopyrite (FeAsS) and/or pyrite (FeS2). Pretreatment of a low grade ore containing 0.4% FeAsS, 3.5% FeS2, and 2.74g/mt Au with 1.2M NaOH, 40 psig 02, 100° C, and 4 hr in
Iron Oxide Pellets
Table of ContentsDesign ProcedureHow It Works Develop methods of enhancing and measuring the high-temperature softening and melting properties of iron oxide pellets reduced under simulated blast furnace smelting conditions. Add dolomite and limestone flux and a low-cost organic binder, such as starch, carboxyl methylcellose (CMC), or waste papermill sludge, to the iron oxide concentrate to produce hematite (ferric oxide) pellets
Laboratory Zadra Electrolytic Cell
Table of ContentsA Homemade DIY Zadra Electrolytic CellZadra Electrolytic Cell ComponentsLaboratory Zadra Electrolytic CellMaterials and EquipmentDesigning a Zadra Electrolytic Cell A ZADRA electrolytic cell adapted to strip gold from sulfide solutions thereof which comprises a cathode assembly having a vertical metallic pipe adapted to deliver gold-bearing solution to the cell and to serve as a negative bus bar for delivering electric