Blogs
Ilmenite Chlorination
Table of ContentsSmeltingStarting MaterialsEquipmentOperating ProceduresResultsOxidation-Sulfation-LeachingChemical Reactions and Theoretical ConsiderationsEquipmentOperating ProceduresResultsMaterial and Energy Balances To help assure an adequate supply of raw materials to meet national economic and strategic needs, the Bureau of Mines undertook research to devise technology to efficiently and economically recover titanium from low-grade domestic deposits. The objective of this research was to devise a means for producing
Chloride Leaching Sulfide Concentrates
Table of ContentsProcess DescriptionApplication of Chloride HydrometallurgyMaterials of Construction The fact that chloride oxidates can solubilize base metals from sulfide concentrates has been known since the 1880’s. The work of Hoepfner in 1902 was particularly accurate for its time with regard to the chemistry of chloride solutions. Recent work has dealt with the understanding of chloride extraction thermodynamics by modelling
Converting Chalcopyrite to Copper Sulfides
Table of ContentsExperimentalResults and DiscussionKinetics of Reaction This is of special interest in hydrometallurgical processing since it provides an upgraded sulfide and rejects iron to solution. Also, the conversion of chalcopyrite is an important process in secondary mineralization during supergene enrichment, and secondary mineralization may occur during long cycles of dump leaching. In deep solution mining, secondary reactions undoubtedly will
Biological Treatment of Cyanidation Wastewaters
Table of ContentsAnalytical and Toxicologial TestingEvaluation of Chemical and Physical Treatment ProcessesDevelopment Of The Biological Treatment Process Metal complexed cyanides in wastewaters form as a result of interactions of free cyanide with metals present in the wastewater and exhibit varying degrees of stability, toxicity, and treatability. Thiocyanate, a pollutant commonly found in cyanide bearing wastewaters, is formed through the interaction
Ball Mill Media Maintenance
Table of ContentsMeasurement of Ball ChargeWeight Loss FactorsMill Performance Summary Improper size distribution of the grinding media in a multicompartment mill can be a source of many operation problems encountered. Inefficient use of the power expended for grinding, and an undesirable product size distribution are two frequent resultants. The objective then is to provide a method which would be practical
HCl Leaching Reactor Design
Table of ContentsMiniplant DescriptionExperimental ProceduresBench-Scale LeachingBench-Scale Attrition TestingMiniplant ProceduresMaterialsDiscussion of ResultsBench-Scale TestsModification of Miniplant ReactorsEffects of Reactor Modification on Miniplant Leaching In the clay-HCl miniplant, leaching sized, calcined kaolin with HCl was carried out in 50-gal, glass-lined continuous, stirred tank reactors (CSTR’s). Originally four reactors arranged in a cascade configuration were used, but experience showed that acceptable alumina extraction was
Aluminum Chloride Hexahydrate from Kaolinitic Clay
Table of ContentsMaterials and ProceduresResults and DiscussionFlowsheetEconomics There has been considerable interest in developing methods to economically produce cell-grade alumina from nonbauxitic materials. In the United States, this interest stems principally from a lack of sufficient bauxite deposits suitable for Bayer processing. In 1973, the Bureau of Mines initiated a program to study the options available for recovering alumina from
Acid Pressure Leaching of Nickeliferous Laterite Ore
Table of ContentsAutoclaving of Laterite Ores High in Magnesium SilicatesCharacterization of the Magnesium Sulfate ScaleMagnesium Sulfate Solubility RelationshipsEffect of Magnesium Sulfate Deposition on Alunite and Hematite Scale Formation The AMAX sulfuric acid leaching process involves countercurrent digestion of nickeliferous laterite ore at high pressure and at atmospheric conditions. After solid/liquid separation, the nickel and cobalt values are precipitated by hydrogen-sulfide
Pilot Plant Graphite Deposit
Table of ContentsPilot Scale Test Set-UpPilot Plant Test ResultsFull Scale Mill DesignPlant Layout Based upon diamond drilling of 100 holes the reserve is estimated at 2,300,000 tonnes containing 8% graphite. The ore is found in two zones. Both ore bodies open at depth and outcrop at the surface. They are separated by about 2000 ft. and occur in clearly defined
Cyanide Biodegradation
Table of ContentsDescription of Cyanide-Contaminated Solutions and ResiduesSample AnalysisExperimental Procedures and ResultsLaboratory Research to Establish Process FeasibilityTreatment of Tailings Pond WaterTreatment of Heap Leach Process SolutionsLaboratory Research to Bacterially Decommission Heap Leach OperationsCyanide Destruction in Process SolutionsCyanide Oxidation in PondsTreatment of Cyanide-Leached Ore Management of mine drainage and mineral processing waste systems is a serious problem that could have major
Pebble Crushing Circuit Design
Table of ContentsIndicatorsEffect of MineralogyTarget Operating Work IndexComparison of Bond Work IndicesGrinding Circuit DesignThe Pebble Crushing Circuit The design of a pebble crushing circuit as an integral part of a North American style primary autogenous or semi- autogenous grinding circuit presents certain challenges to the process design engineer. Initially, the process requirement for pebble crushing has to be determined as
Mechanism of Sulfur Oxidation in Pyrite
Table of ContentsCyclic VoltammetryImpedance Spectroscopy The Mechanism of Sulfur Oxidation in Pyrite is base on what is generally believed as anodic oxidation of pyrite occurs according to the reactions to form S° and SO4=. FeS2 = Fe++ + 2 S° + 2 e-…………………………………………………………………….(1) FeS2 + 8 H2O = Fe+++ + 2 SO4= + 16 H+ + 15 e-…………………………………(2) Pyrite crystals were
Pressure Oxidation of a Refractory Sulfide Concentrate and Thiourea Leaching of Gold and Silver from the Residues
Significant advances have taken place in the treatment of refractory gold ores and concentrates during the past decade. In sulfide ores, pyrite is the most common host mineral for gold. Studies by Gasparrini (1983) showed that gold occurs in pyrite as native gold or electrum in all sizes and forms. Arsenopyrite is probably the second most common host for gold and
Magnetic Reagents
Table of ContentsMagnetic Reagent and its FunctionsAdsorption of Magnetic ReagentPotential Applications to Minerals ProcessingCoal Cleaning with Magnetic ReagentProperties of Magnetic ReagentCoal Cleaning The behavior of fine mineral particles in a slurry is difficult to control, presenting a serious problem in many processes. At fine particle sizes, gravitational force is weak. Electrostatic force, although strong in dry conditions, can rarely be
Dry Gravity Separation
Table of ContentsPrinciple of the Advanced Two-Way DGSConditions for a Successful SeparationCase Histories The basic principle of this separation method was already defined in the middle of the nineteenth century. However, a change over for the treatment of minerals has followed from the construction of proper machines i.e. airjigs and airtables as late as in the twenties and thirties of
Peroxide Leaching of Gold Silver Sulfide Flotation Concentrate
Table of ContentsConcentrate Leach CircuitProcess TheoryTest ProgramPAL Economic BenefitsFeed System The alternatives considered for accelerating the concentrate leach kinetics were addition of air or oxygen, and Degussa Corporation’s peroxide-assisted leaching (PAL) process. Air addition was tried, but only produced a voluminous froth which overflowed the leach tank, because of the presence of residual concentrations of flotation reagents. Therefore, addition of
Chemoremediation of Acid Mine Drainage
The chemical alteration of water by acid mine drainage begins with the exposure to the atmosphere of pyrite associated with coal during the mining process. The exposed sulfide minerals, which are relatively insoluble in their original state, are converted by oxidation to soluble sulfuric acid, which in turn dissolves other minerals containing manganese, aluminium and calcium. FeS2 + 3O2 +
Sediment Compressibility in Thickening of Flocculated Suspensions
Polymeric flocculants are widely used to enhance particle sedimentation in the application of thickening processes to slurry dewatering. When properly applied, these flocculants promote the formation of large flocs which settle rapidly and provide for effective water clarification through the efficient capture of fine, suspended solids. However, the flocs formed are generally of very low density and the rapid, initial
Comminution Model Types
Table of ContentsMill Power Draw ModelsSpecific Energy ModelsPopulation Balance ModelsDiscrete Element ModellingConclusion Many types of mathematical models are used in comminution and mineral processing. These models can generally be classified into one or more of the four categories shown above. Mill Power Draw Models The purpose of a mill power draw model is to predict what the mill power and/or
Calculation of Mineral Liberation in a Continuously Operating Ball Mill
Table of ContentsExperimentalThe Comminution Model The calculation of the liberation spectrum in the product from a continuously operating ball mill is both important and difficult The liberation spectrum depends on the mineralogical texture of the ore from which the mill feed derives and also on the processing steps through which portions of the feed have passed prior to milling. These
Kinetics of Coal Flotation
Table of ContentsMaterials and MethodsResults and DiscussionEffect of Particle Size on the Flotation Effect of Particle Size at a 100-mesh GrindSummary and Conclusions Desulfurization of coal before combustion is becoming important for the effective utilization of this major energy resource without polluting the environment. Because most sulfur-bearing and ash-forming minerals are finely disseminated in the coal matrix, raw coal must be
Mill Matrix of Distributed Comminution Models
Distributed Component Comminution Model The general form of the comprehensive distributed component comminution model has been described as follows d/dt(m(t)) = – [I – B]S m(t) = A m(t)…………………………………………..(1) Where A is the fundamental matrix/state companion matrix or the so-called mill matrix in comminution literature. The reason being that A as a general real matrix may have complex eigen-values and complex
Direct Fuming of Zinc in Sulfide Ores & Concentrates
Minproc has developed a process concept of preconcentration of zinc and tin to moderate grade preconcentrates at high recovery, followed by pyrometallurgical upgrading (filming) of the preconcentrates to high grade, saleable oxide fumes. Broadly, concentrate grade is inversely proportional to recovery, and while high recoveries of zinc and tin can be achieved into low grade concentrates, attempts to produce high
How Ball Mills Lifter Bar Affects Charge Motion
Table of ContentsThe Numerical MethodNumerical ResultsPower Draw In ball mills, the grinding of ore bodies takes place due to the impact and attrition of the colliding balls. For efficient grinding of hard materials, high-impact velocities are required. For a given rotating speed and filling of the mill, impact velocities of balls and the nature of forces developed inside the mill