Blogs
Hemi-Micelle Formation – Hydrocarbon Chain Role in Alkyl Flotation Collector
Table of ContentsMicelle HypothesisHemi-Micelle Hypothesis The marked changes in electrokinetic potentials of quartz in dodecylammonium acetate (DDA) solutions were postulated to result from the association of adsorbed collector ions into two-dimensional aggregates, called hemi-micelles. The rapid increase in flotation rate of quartz was shown to coincide with hemi-micelle formation. Micelle Hypothesis In dilute solutions alkyl ammonium and related salts behave
Ball Mill Scale-up Method
Ball Mill Scale-up by this method is known as collision energy based population balance model. The appropriateness of this model is shown for 38-cm ball mill. Comminution in ball mills account for a significant amount of power consumption in mineral processing plants. Therefore, accurate modeling of the process is extremely important to optimize the power consumption, which can lead to
Copper Activation Sphalerite & Xanthate
Table of ContentsApparatus and ProcedureContact Angle Measurements Copper Activation Sphalerite & Xanthate: Unlike most other sulfide minerals, sphalerite responds poorly to short-chain thiol collectors. The problem is attributed to the high solubility of zinc-thiol compounds in water. Also, due to its large band gap (3.7 eV), sphalerite is a poor catalyst for mixed potential reactions between xanthate and oxygen. The
Heavy Minerals Sands Processing by Rare Earth Magnets
The first known attempts to apply a REM roll separator to a heavy mineral sands application were made in South Africa and Western Australia in 1985. At that time, an ilmenite beneficiation process, which was normally achieved with cross-belt separators, was tested with a full-size machine. The performance was not good because only a single separation pass flow sheet was
Gold Pyrite, Pyrrhotite and Arsenopyrite Recovery
One of the more common classes of ores containing gold is when gold is associated with pyrite, pyrrhotite, and arsenopyrite. This is the area of gold recovery that has probably received the most research and plant optimization support especially in light of the long history of South African industrial practice. From a reagent viewpoint, charged water soluble collectors such as
Dense Sludge Process
Figure 1 presents a simplified process flow diagram of the Dense Sludge process. The most significant change between Dense Sludge technology and conventional metals treatment is the method by which the alkali source is added. In conventional treatment systems, the alkali is added directly into the influent to achieve a desired pH setpoint. Generally, that setpoint is the pH at
On-Stream Analysers Benefits
What are the benefits of having an OSA on-stream analyser? The assays are utilized for control in many ways, starting from individual control loops to overall optimization in the flotation circuits. Reagent dosages in the cleaner flotation stages are controlled by feedback from concentrate quality. For instance, the depressant in the zinc cleaner circuit is adjusted by to the sequence
Carbonaceous Gold Ore Treatment Method
Table of ContentsFlotationCyanide Leaching with Carbon or Resin in PulpRoastingChemical Oxidation Flotation The simplest method of treating a carbonaceous ore is the method described by R. W. Nice (1971) at the McIntyre Porcupine Mine where the carbon, which contains very little gold, is floated off and discarded. The remaining ore is then responsive to cyanidation. This does not work at
Thiourea Silver Leaching
Unlike base metals which are readily soluble in mineral acids, noble metals like gold and silver require the presence of oxidizing and complexing agents for dissolution. Silver approaches base metal behavior in acidic thiourea solutions (Ag + 3Thio ↔ Ag(Thio)3+ + e, E° = 0.025 V) requiring only mild oxidizing conditions for dissolution. Accordingly, the following reactions characterize the dissolution of
Ferrosilicon Powder
Table of ContentsFerrosilicon as a Heavy MediumFerrosilicon Powder Manufacturing ProcessBy GrindingBy AtomizingProperties of Atomized Ferrosilicon1. Corrosion2. Viscosity of Pulp3. Adhesion — Losses4. Strength Properties Ferrosilicon powder (containing approx. 15% Si) for constitution of heavy media is used today in many separation plants treating iron and other ores. The production of the powder by grinding is expensive. A new process atomizes the
Blast Hole Liner
Table of ContentsSafe Working Procedure for Inserting the Blast Hole LinerThe Blast Hole Liner Site Test TrailStep by Step Procedure for Inserting the Blast Hole LinerContact Clayton Hitchcock Causes of Malfunctioning BlastholesInsufficient Energy ReleaseInitiators Error or IncompatibilityExecution of the Blasting Plan Designed to provide quick, hassle free lining of blast holes on the go. Blast Hole Liners are securely packaged in convenient
Rock Stability Tester
Aid mine workers in detecting hazardous roof conditions in underground mines by developing a method of roof sounding which supplements or replaces the traditional roof sounding technique where the miner relies on experience to determine whether or not the rock is sound. The Bureau of Mines developed an electronic roof sounding device that acoustically determines the integrity of mine roof
Magnesium Oxide to Remove Metals in Water
Table of ContentsForms of MagnesiaElectrical Phenomena at InterfacesDual Role of MgO as a Filter and PrecipitantExperimental ProcedureResults and DiscussionHeavy-Metal Retention of MgO Filter BedsStripping of Heavy Metals from MgO Filters Conventional practice for treating mine drainage and other water sources contaminated with heavy metals is lime precipitation and settling of the hydrous oxides. This produces a voluminous toxic sludge that
Gold Trommels & Gold Scrubbers
Table of Contents Trommel Construction DetailsScrubber OperationPerfect Tire ConcentricityCapacitiesScrubber or Log Washer Gold Trommels & Scrubbers are noted for economy and efficient performance in cleaning sand, gravel, crushed stone and various ores. These machines are ruggedly constructed and are designed for excellent results with a minimum of water, power and maintenance. Time and again users report lower cost per ton with
Rock Cutting Equipment
Table of ContentsRadial BitPoint Attack Pick (Conical) Mechanical excavators were introduced for soft rock cutting at the time of the industrial revolution. The early machines date back to mid 1800’s and were developed for rapid excavation of tunnels and to increase production in the mining environment. The early radial or drag type tools were very primitive and made of hardened
Air Decking to Increase Fragmentation in Blasting
Table of ContentsSub-drilling reductionPlug Selection ChartBenefitsDownstream SavingsDrilling ProcessDetonation PathBlasting ResultsMid Hole DeckingStep by Step GuideCASE STUDYContact Clayton Hitchcock Development of Fragmentation System Design (FSD) Better Air Decking using the Saver Plug, offers a reduction in fly rock, vibration, drilling costs, and the volume of explosives used in blasting. It is used across all sectors of the mining industry, including underground horizontal hole
Drying Coal by Microwave
Table of ContentsExperimental ApparatusCoal Samples and PreparationExperimental ProcedureResults and Discussion Fundamental problems exist with the drying of fine coal. The moisture content of fine coal after mechanical dewatering is often too high to allow the coal to be added directly to the coarser (plus ¼ in) fractions and it must be further dewatered. Also, fine coal is lost and expelled with
Hydrostatic Bearing Type Center Mechanism
Development of the Hydrostatic Bearing Mechanism evolved from the caisson thickener design. Conventional thickener mechanisms are driven by gearing which rides on ball or roller type anti-friction bearings. It would not be feasible to use this method of support with a very large diameter bearing, especially with high torque, vertical and unbalanced loads. Additional stresses are produced in large bearings
Floating Gold Wash Plant
Figure 125, A and B shows typical arrangements using floating gold washing and gold-saving plants (“boats”). Figure 125, C, is a plan of an operation where the gravel is first dug by a power shovel and is then picked up by a dredge equipped with a light bucket line. Where floating plants can be employed, operating costs usually are lower
Hydraulicking
Hydraulicking: In hydraulic mining a stream of water under high head is employed to break down the bank and excavate the gravel and to sweep it to the sluices. Additional running water (termed “bank” or “by-wash” water) usually is required to wash it to and through the sluices. The gold is recovered in part from cleaning the bedrock after the gravel
Dewatering Clay
Table of ContentsSmall-Scale Dewatering ExperimentsLarge-Scale Clay Dewatering Experiments Phosphatic clay waste is one of the principal waste products resulting from the mining and benefication of Florida phosphate ore. This waste material, which is comprised of ultrafine particles (70 pct less than 1 µm), responds poorly to conventional solid-liquid separation techniques and is currently disposed of by impoundment behind earthen dams. The overall
Marked Ball Wear Test
Table of ContentsResultsMarked Ball TestingMarked Ball Wear TestsSurface Morphology of Grinding BallsElectrochemical MeasurementsMarked Ball Wear TestsLaboratory Batch Flotation TestsPercent Martensite Hardness Marked Ball Wear TestsScanning Electron MicroscopyLaboratory Batch Flotation Tests Marked ball wear testing described in a 1948 paper by Norman is an invaluable test method to measure relative and/or absolute wear rates of balls under identical mill operating conditions.
Flameless AAS Atomic Absorption Spectroscopy
Table of ContentsInterferencesDetermination of Gold and Silver from a Single Sample Preparation Flameless AAS provides a means to increase flame AAS sensitivity, by up to 200 times. Interferences from aqueous leachates and digestates are so great, however, that flameless AAS has found application mainly after organic extraction. Thereby, the analytical sensitivity is increased far beyond that of the SX/flame- AAS
Neutron Activation Analysis for Silver
Gold values in the surveyed sulfide-poor rock units proved to be generally even lower than those in sulfidic sandstone. As a further check on this survey of mineralization, silver values began to be measured by NAA on the silver-gold beads. Radioactivity induced in silver by neutron bombardment is long-lived. The half-life of 110mAg is 253 days, as opposed to a