Blogs
Cobalt Beneficiation Technique
Objective Develop new technolgies and techniques which enable recovery of strategic and critical minerals such as cobalt from domestic resources, thereby easing the U.S. dependence upon foreign producers for these valuable commodities. Approach The Bureau of Mines, through research, developed a process which uses mineral beneficiation techniques to recover cobalt-rich products from Missouri lead ores. Before development of this process,
How to Predict Electric Motor Failures
Table of ContentsRecent Failure Prediction ResearchFailure Prediction Research ResultsMethodologyTheoretical Analysis of AlgorithmSystem SpecificationSystem StructureSystem OperationSystem UtilityModel DevelopmentCable-Connected Motor ModelsInduction Motor Deterioration ModelComputer AnalysisCable DeteriorationMotor DeteriorationExperimental ProgramDeteriorating-Motor ExperimentsDestructive TestingElectrically Excited VibrationTheoretical StudyLaboratory ExperimentsPractical Applications of Research ResultsComputer Model UseOff-Line Failure Prediction TechniquesU. S. Navy Submarine Power System MonitoringSubmarine Data Acquisition A system capable of monitoring a mine electrical power system to
Gravity Recovery -500 Mesh Particles in Jig
The packed jig is a column filled with corrugated diagonal packing. A slurry of mixed particles, the ore, is fed into the middle of the column. Water enters the column near the bottom as both a steady state and a pulsating flow. The pulsating water sets up a jigging action that interacts with the packing causing the dense particles to
Ore Cutoff Grade Optimisation
Table of ContentsCutoff Grade Optimization for a Gold DepositOperating Cash Flow Analysis for Break-even Cutoff GradesOperating Cash Flow Analysis for Optimum Cutoff Grades We will discuss the fundamental elements of cutoff grade optimization and demonstrate how cutoff grade optimization may improve NPV of a given operation under different scenarios. The first case study is a description of cutoff grade optimization
Heap Bio-oxidation of Sulfide Concentrates
Table of ContentsGeobiotics Heap Bio-oxidation of Sulfide Concentrates ProcessAeration Low-cost oxidation pretreatment technologies are needed in order to economically extract precious metals from refractory sulfidic deposits as the world’s free-milling reserves are consumed. Already, more than one-third of the gold ore reserves in the United States are considered to be refractory. Many of the deeper gold deposits that are currently
Laboratory Continuous Dynamic Thickening Tests
Table of ContentsEffect of Polymer on Overflow ClarityEffect of Polymer Addition on Underflow DensityEffect of Polymer Addition on Thickener CapacityEffect of Feed ConcentrationEffect of Rake Speed Dynamic tests were conducted in a laboratory continuous thickening system. This system, shown in Figure 1, consists of a 3½ in. (89 mm) ID and 20 in. (508 mm) height lab thickener/clarifier equipped with
How to Remove Soluble Manganese
Table of ContentsAdsorption Tests in a Batch ReactorAdsorption Study in a Fixed Bed Column The granular media used for the study of soluble manganese removal included natural manganese oxide ore. The manganese oxide ore of South Africa origin obtained from Elkem Company (Marietta, OH) was used as the medium for soluble manganese removal. The raw manganese oxide ore sample was
What is Zeolite used for
However, in a number of applications, natural zeolites have inherent advantages, not the least of which is that natural zeolites cost much less than the synthetics. Fish and Shellfish Farming: Clinoptilolite (clino) can remove ammonia in aquaculture ponds and tanks. Clino has been successfully used in biofilters, regenerable ion exchange beds and pressure filters; and will reduce fish losses thereby
Yield Index – Flotation Result Analysis
A new procedure for determining the optimum separation for any unit operation. This procedure is based on maximization of the yield index, YI, which is the product of the yield (or valuable recovery) and gangue rejection. In addition, the characteristics of the yield index and the separation efficiency are compared and contrasted. As indicated earlier, the separation efficiency is the
Superconducting Magnetic Separators
The phenomena of magnetism is well known. The way in which materials respond to a magnetic field can be predicted and the design of magnet systems is now regularly modelled on computer. The real step forward has been in the use of superconducting wire wound magnets that enable much higher fields to be generated. Conventional and familiar is the generation
Silver Chloride Precipitation & Separation
The unique insolubility of silver chloride makes it possible to readily achieve a distinctive separation of silver from a mixed metal ion acidic solution. Using chloride precipitation with NaCl solution, the plant operation selectively removes all the silver from the pressure leach solution. The chemistry is quite straightforward and effective. As with most processes, it can be achieved in a
Colemanite Clay Flotation
Floatability of colemanite was determined using a 150-ml column cell (25 x 220 mm) with a fine fritt and magnetic stirrer. One gram of sample was conditioned in 150 ml of a solution containing SDS for 10 min. and floated for one min. using nitrogen gas at a flow rate of 50 cm³/min. The microflotation tests were performed by an
Acid Activated Montmorillonites Uses
Table of ContentsEdible oilsPetroleum applicationsCatalytic applications Non-swelling calcium montmorillonite is mined from bentonite deposits and treated to produced acid-activated powders and granules for use as separation products and catalysts. In particular, acid-activated montmorillonites are used as sorbents for removing impurities from fats and oils, as catalysts for mineral oil processing and for a number of other applications. These smectite group
Column Flotation Cell Baffles
Table of ContentsBaffled Column Flotation of a Coal Plant Fine-Waste StreamTheoretical DiscussionProcedures The increased use of flotation columns is due to their superior separation efficiency compared to conventional flotation. This increased efficiency can be attributed to: The countercurrent movement of slurry and air bubbles increases the probability of bubble / particle attachment. This is accomplished by larger aerated volume of
First Order Flotation Rate Equation
Many investigators showed that mineral flotation can be described as a first-order process (Sutherland, 1948; Tomlison and Fleming, 1963). In this case, the rate of flotation can be represented by: dN/dt = -kN……………………………………………………(1) where N is the number of floatable (or hydrophobic) particles present in a flotation cell and k is the rate constant. It has been shown that :
Palladium Leaching in Ammonia
Recently, a number of techniques of recovering Palladium have been developed. For example, leaching of platinum group metals from spent automobile catalytic converters using halogen salt with oxygen was developed. Ammonia is an inexpensive lixiviant used in leaching precious metals such as silver and gold. Since palladium has some similar chemical properties to silver, it is believed that ammonia leaching
Chalcopyrite Leaching by Iodine
Chalcopyrite is the most abundant mineral of copper sulfide minerals and the major source of copper. Numerous leaching processes, such as ammoniacal systems, acid sulfate systems, chloride systems, and nitrate systems, have been introduced and investigated. In oxygenated ammoniacal solutions, chalcopyrite dissolves according to the following reaction: CuFeS2 + 4NH3 + 17/4 O2 + 2OH- = Cu(NH3)4²+ + ½Fe2O3 + 2SO4²-……………………………(1)
Types of Pressure Oxidation Autoclave Lining
As shown in Figure 1, there are other accessory vessels (splash and flash towers) in the autoclave circuits, that are also brickwork lined. The linings used to date, other than small test sections, have all been acid-resistant fireclay bricks, bonded with alkali silicate mortar, PbO-based mortar, and/or vinyl ester mortar, but mainly alkali silicate mortar. Several different zones exist within
Coal Washing Plant
The calculation of the performance of coal washing units that are in common use is not difficult and the principles of making such calculations have been known for many years. The flowsheets to be simulated consist primarily of coal washing units each with a target specific gravity of separation specified for each washing unit. The feed is allocated to each
Flotation of Low Quality Coal
To understand interactions between physical and chemical variables, a synthesis rather than an analytical approach is needed. In analytical approach, sub-processes of a system are isolated to determine the cause and effect relationships between performance of the sub-process and the system variables, whereas in synthesis approach a global view is taken to identify various interactions. A schematic representation of the
Hypochlorite Leaching of Gold Ore
The reactions between gold and hypochlorite leach solutions containing hydrochloric acid and sodium chloride are demonstrated below: 4Au + 16NaOCl + 10H2O → 4HAuCl4 + 16NaOH + 5O2……………………………………(1) 4HAuCl4 + 4NaCl → 4NaAuCl4 + 4HCl…………………………………………(2) 16NaOH + 16HCl → 16NaCl + 16H2O…………………………………………(3) Overall reaction of equations (1), (2) and (3) can be summarized as follows: 4Au + 16NaOCl + 12HCl → 4NaAuCl4 + 12NaCl
Leach & Recover Gold from Black Sands
Black sand may be generally defined as a constituent of “alluvial” gravel consisting mainly of fine particulate grains of heavy, dark colored minerals and rocks. These alluvial gravels, chiefly concentrated by wave, current or surface action, may also contain “eluvial” material that includes black sand. The eluvium, which results from decomposition or disintegration in place of an ore body, may
Fine Gold Recovery by Flotation
Table of ContentsMechanical Fine Gold Flotation CellAir Sparged Hydrocyclone Gold Flotation Column In view of the tendency of fine gold recover by floating and the dominance of heavy minerals, the prospects for flotation were worthy of re-investigation, particularly with the new tools of the air sparged hydrocyclone (ASH) and the flotation column. Although gold readily and naturally forms a hydrophobic film,
Grinding Ball Design
Table of ContentsBall Design FactorsSize and MassHardnessBall quality control for mill operatorsConclusions Grinding balls are essential mechanical components in ball and semiautogenous (SAG) mills. Their function is crushing and grinding ore rocks weighing up to 45 kg (100 lb) preparatory to recovery of valuable minerals, from lead through rare earth elements, which are essential to the approaching 21st century technological