Blogs
Control Water Flow during Shaft Sinking
Table of ContentsAssessing the Location & Amount of WaterPredicting Water InflowSelection of Water Control Method The importance of controlling water inflow during shaft development has been well known to those faced with the problem. Depending on the amount, temperature, and quality of the water, the extra costs of working in wet conditions can easily be several times that for the
Water Clarification by Flocculation
Table of ContentsCylinder Settling TestsLaboratory Cylinder Settling TestsOn-Site Cylinder Settling Tests The chemicals involved in the work of this paper utilize a combination of mechanisms: charge effect neutralization and polymer bridging. There are a number of trends in the results that support this dual mechanism. The slow settling rate and insensitivity of changes in coagulant concentration are the typical effects of
Acidic Mine Tailing Neutralisation – Vegetation
Table of ContentsSite Description and ClimateCharacterization of TailingField Test ProceduresEvaluation of Field Tests Field tests on 20-year-old acidic copper tailing showed that after treatment with combinations of dolomitic lime, limerock, fertilizers, and/or sewage sludge, vegetation can be successfully established. Plant coverages, 4 years after seeding, ranged from 30 to 80 percent, even though neutralization of the acidic tailing with either
Zinc Electrowinning & Zinc Cathodes
Table of ContentsExperimental ProcedureMaterials and EquipmentElectrolyte PreparationOperating the Electrolytic CellAnalysis and EvaluationResults and DiscussionPreliminary Work Using Reagent-Grade ZnOWork With Fluoride-Containing Zinc ConcentratesPurificationRe-solutionFluoride ConcentrationSolution-Level CorrosionFinal Test With a 10-Liter CellConclusions Commercial production of zinc by electrolysis began in 1881 following a patent by Letrange of France. The process has come down to the present day essentially unchanged and consists of three
Titanium Oxide or Titania Pigment by Ilmenite
Table of ContentsPreparation of Titanate Intermediate ProductsSimulated Sulfate-Process ExperimentsUsing Hst and Lst as Feed MaterialsLaboratory ProceduresResults With HST and LST Feed MaterialsAcid RegenerationUse of Regenerated AcidConclusions Titanium dioxide or titania pigment is prepared commercially from ilmenite, an iron-titanium oxide mineral, by the sulfate process. Ilmenite is digested with H2SO4 to yield a titanium sulfate solution. Subsequently, the solution is hydrolyzed
Structural Analysis of Grinding Mill Shells
Table of ContentsStress EvaluationFatigue Life DiagramsFracture Mechanics Methods Accurate modeling of structures by finite elements requires not only that the user estimate the load paths, and areas of stress concentrations or rapid variations, in a structure, but also that he realize the modeling idiosyncracies of each element he is working with. He needs to know limitations in displacement function assumptions,
Belt Conveyor Reclaim Tunnels
Table of ContentsSingle TunnelSequential TunnelConverging TunnelsParallel TunnelsBucketwheel ReclaimersUniform Material FlowStockpile Reclaiming Equipment and Arrangements Whenever the material and soil conditions permit its use, a belt conveyor in a reclaim tunnel is the most economical reclaim device due to its very limited manpower requirements and utilization of gravity to make the ore flow to the feeder opening. This dependence on material
Aluminum Chloride Solubility
Table of ContentsApparatusExperimental ProcedureAnalysisResultsComparison With Other DataThermodynamic TreatmentSolubility Product and Activities in AlCl3·6H2O-H2O SystemEstimation of Activities in AlCl3·6H2O-H2O SystemSolubility product and activities in AlCl3·6H2O-HCl-H2O systemEstimation of Activities in AlCl3·6H2O-HCl-H2O SystemAlCl3-FeCl3-KCl-NaCl-HCl-H2O SystemAreas Recommended for ResearchAluminum Chloride in Aqueous Hydrochloric Acid Solutions A research program was conducted to improve processing technology for extracting alumina from nonbauxitic. The success of this program had provided the
Sizing and Operating Thickeners
This paper presents a development of thickening theory which provides a reliable and easy-to-use method for determining the size of continuous thickeners from batch settling tests. It also offers a description of thickener operation performance based upon the proposed method. Thickener Operation Figure 13 shows a log-log relationship between underflow concentration and unit area at various interface heights for a
Accuracy Determination for Conveyor Belt Scales
Table of ContentsConveyor Belt Scale AccuracyConveyor Belt EffectsPractical Procedures Increasing capacity of bulk material handling systems creates difficult problems for accurate in-line material weight measurements. At the same time increasing system complexity and growing user demands call for more measurements. Precision in-line weight measurements for bulk materials are usually accomplished by application of conveyor belt scales. Belt scale accuracies listed
Secondary Crushing Simulation
Table of ContentsEffect of % +1 Inch in Secondary Crusher FeedEffect of Secondary Crusher Close Side SetEffect of Secondary Screen OpeningEffect of Tertiary Crusher Close Side SetEffect of Plant Variables on Crusher Currents The crushing plant simulator was utilized to evaluate the influence of major variables on the following responses: plant reduction ratio , weight % of -½ inch material
Dust Scrubbers
Table of ContentsDust Collection Efficiency RequirementsData AnalysisVenturi ScrubbersResultsAmerican Air Filter ScrubberResultsFlooded Fibrous Bed ScrubberResultsVortex Flooded Fibrous Bed ScrubberResultsA-Par Air WasherResultsCommentsRotating Flooded Fibrous Bed ScrubberResultsConclusionsLaboratory Test FacilityDust Sampling ProcedureDust Sampling AnalysisExperimental ProblemsAir LeaksDust LossCondition 1Condition 2Drift in Dust Concentrations Currently, most coal mines rely primarily on two methods for controlling dust. The first utilizes large volumes of outside air to ventilate
Waste Chromic Acid – Sulfuric Acid Etchants Regeneration & Recycling
Table of ContentsThe Regeneration ExperimentSpent EtchantsThe Diaphragm CellResults and DiscussionBench-Scale StudiesLarge-Scale StudiesSummary Two of the missions of the Bureau of Mines are to conserve scarce, costly metals and to reduce pollution. In accordance with these missions, the objective of this investigation was to develop a method of recycling spent chromium etching solutions that are now discarded as wastes. Solutions containing
Aluminum Dross Furnace Salt Slags Processing
Table of ContentsPreliminary ExperimentsPrinciples of OperationLeachingScreeningSlurry FiltrationEvaporationProductsProcess EvaluationCapital CostsSalt Slags Processing Operating CostsProfitabilitySalt Slag Processing ProblemsAluminum Dross Furnace Summary Disposal of the salt slag produced during the processing of aluminum dross and scrap is of particular interest to the secondary aluminum industry. Melting of these materials is carried out under a salt flux cover to dissolve the contaminants, mostly aluminum
Platinum Electrocatalysts for Oxygen Reduction
Table of ContentsMaterial PreparationElectrode PreparationTest Cell Construction and OperationResults and DiscussionSummary This report describes possible material application as oxygen electrode catalysts. The ultimate objective was to assess the potential of abundant, less costly materials as substitutes for platinum, or to increase the efficiency of platinum when used as an oxygen electrocatalyst. Presently, imports account for essentially all of the U.S.
Slurry Flow Rate Through a Mill
The factors upon which the rate of flow of the pulp through a mill depends appear not to have received extensive investigation. In an article by Anselm translated by Pearson a method for the calculation of the time of passage of cement through a ball mill was given. The basis of the method is that the volume rate of throughput is
Grinding Mill Surging
The phenomenon of “surging” in a mill is a subject upon which very little has been written; presumably because it is a condition which cannot be tolerated in mill operation and which must be eliminated by variation of some or many of the physical dimensions or characteristics of the mill or mill charge. The phenomenon known as “surging” consists of a
Effect of Grinding Media on Milling
Table of ContentsEffect of Ball Diameter, or Rod Diameter VariationGrinding Media Density VariationsMill Efficiency & Mill FillingEffect of Balls Hardness on Rate of Grinding Size Distribution of the Balls in the Mill Charge In the previous chapter the influence of the various physical quantities defining the mill and mill charge has been studied in connection with the performance of a mill as a device for
Mineral Processing Plant Sample Equipment
Table of ContentsEnclosed or Chute Type Samplers and Vezin’sWet SamplingEnclosed or Pipe Type Samplers and VezinsDry Sampler SystemsFeedersSecondary SamplerCrushersTertiary SamplersRejectsChuteworkSample CollectorElectrical ControlsWet Sampling SystemsPrimary SamplerSecondary SamplersInterconnecting Pining and TanksRejectsSample CollectorControls Coarse-ore dry sampling of the type found in primary and secondary crushing systems prior to processing, often requires sampling large flow rates containing 2″ to 6″ particles. The cutter width
pH Control in Solvent Extraction Circuits
Table of ContentspH Controlled ExtractionConclusion The control of pH in solvent extraction circuits is an old technique but one which has a large potential for future use. The equilibrium position of any reaction which has hydrogen or hydroxide ions, either as products or as reactants, can be controlled by pH adjustment. Several examples of reaction types which are important in
Effect of Pulp Rheology on Grinding Mill Power
The dependence of the power demand of a mill on the nature of the pulp does not appear to have received a great deal of study, and, in general, observations on this matter take the form of general statements. For example, Taggart states that, other things being equal, wet milling requires 60-90 % of the power for dry milling. This view
Improve Heap Leaching Percolation Rate
Table of ContentsEquipment, Materials & ApparatusInvestigation of Process VariablesBench-Scale Tests on Silver Mill TailingsBench-Scale Tests on Clayey Gold OreProcess Development Unit TestsPotential Benefits Using Agglomeration TechniquesHeap Leaching Gold Silver Ores To insure the continuing viability of the domestic minerals and materials economy and the maintenance of an adequate minerals base, the U.S. Department of the Interior, Bureau of Mines, has been
Oxide Copper Leach Modeling
Table of ContentsExperimentalMathematical FormulationResults and Discussion In recent years interest in hydrometallurgy, particularly in the case of in-situ leaching and solution mining has remained at a high level. There are several studies published on the development of scale-up principles. D’Andrea and Runke described research on in-situ copper leaching at the Emerald Isle Mine whose dominant copper mineral is chrysocolla. The