Blogs
Heavy Media Analysis – Ericsson Cone Separator
Where large samples (both in top size and weight) have to be examined it is not practical to use heavy liquids (being both expensive and time consuming). A laboratory heavy media separator may be used which simulates the action of a heavy liquid bath. Here is a schematically shows an Ericsson cone separator. Sized fractions of particles in the range of
Specific Gravity Distribution (Tolerance) Curves
The three types of curve described so far completely define the behaviour of the material in a heavy liquid under ideal sink-float conditions. In practice, we wish to use the data to predict the performance of a commercial process such as D.M.S., Jigs, Tables, etc. In these processes, the S.G. of separation will vary between certain limits about a mean
Characteristic of Elementary Assay Curve
The incremental assays obtained for each S.G. are plotted against the average cumulative % weight of sinks and floats. This curve shows the assay of the richest particles in a float or sink. If it is used in conjunction with the cumulative assay of floats or sinks curve, it indicates the spread of assay values obtained in a given product. A
Cumulative % Assay of Floats or Sinks Curve
The cumulative % assay of the floats or sinks is plotted against the cumulative % weight of the floats or sinks. These curves indicate cumulative assay that the cumulative floats or sinks will have at a particular S.G. of separation. They are used in conjunction with the S.G. curve and can thus predict the weights and assays of the two
Washability Curves
Heavy liquid data can also be interpreted by washability curves. To plot these curves, the axes shown here. The cumulative % wt. Floats or sinks is plotted against S.G. If the material consists of two minerals completely liberated from each other, the curve will be a stepped line. The width of the step indicates the S.G. difference between the
Tromp Curve – Example of Partition Curve
As may be seen from the table, a separation at S.G. 2.75 would result in a float product of 68.5% of the weight contain 3.8% of the tin of that size fraction. Laboratory separations in heavy liquids are “ideal” – all the sinks should report to the sinks and all the floats to the floats. In industrial applications heavy media
Drop Weight tests (DWT) using JKMRC Rotary Breakage Tester
The Drop Weight tests (DWT) by JK is now replaced by the JKMRC Rotary Breakage Tester. It is faster as confirmed by Tony and now used by many since its intro http://www.min-eng.com In an AG/SAG mill there are two main mechanisms of breakage, namely impact (high energy) and abrasion (low energy). The industry accepted JK impact breakage parameters, A and b, can reliably
Dense-Heavy Medium Separation HMS / DMS Process
HMS and DMS are acronyms for Heavy (Dense) Medium Separation and is applied to the process of pre-concentration of minerals – mainly the production of a high weight, low assay product, which may be rejected as waste. In principle it is the simplest of all gravity processes and is a standard laboratory method for separating minerals of different specific gravity. Fluids
Agglomeration of Particles
Agglomeration is the formation of aggregate by the sticking together of feed and/or recycle materials, and it includes the formation of agglomerate nuclei. The main objective in agglomerating fines being the conversion of ores, minerals and chemicals of undesirable fineness into agglomerates characterised by a size consistency desirable for subsequent use or processing. In metallurgical applications, the unit process of
Factors Affecting Filtration Rates and Cake Moistures
Here is a list of all Factors Affecting Filtration Rates and Cake Moistures in plants or laboratory de-watering systems and processes. Particle Size of Solids Generally the large the particle size, the higher the filtration rate in Kg/m2/h and the lower the cake moisture. However, the validity of the last statement depends on other factors, e.g. distribution specific gravity of
Filtration – Leaf Filter Testing
Table of ContentsLeaf Filter TestingLaboratory Pressure Filtration Filtration is defined as the separation of insoluble solids from a liquid by forcing a portion of the liquid through a porous medium by a pressure differential, while the solids are trapped on the surface or in the depth of medium. The two main methods that exist to create the required pressure differential
Types of Crushers
Crushers may be divided into three general classes, with respect to the manner in which they do their work: Pressure Crushers: This category embraces the several types of gyratory crushers and jaw crushers, as well as the double crushing rolls, with either smooth or corrugated shells. Impact Crushers: This division is represented chiefly by the various styles of hammermill; also
Impact Crusher Working Principle
Table of ContentsRock Particle Breakage in Impact CrushingTest Procedures for the Characterization of Crusher Performance Starting from the base working principle that compression is the forcing of two surfaces towards one another to crush the material caught between them. Impact crushing can be of two variations: gravity and dynamic. An example of gravity impact would be dropping a rock onto
Principle of Operation of Hydrocyclone
The Principle of Operation of Hydrocyclone is, in simple terms, the forces of gravity and centrifuge to separate large or heavy particles from smaller and lighter one. When sized correctly will “cut” like the ‘real cyclone’ below VS the imaginary ‘ideal’ one on the left. Hydrocyclones are preferred units for sizing or desliming large slurry volumes cheaply and because they
Froth Flotation System
Successful industrial practice has shown that froth flotation sytem needs to be viewed both at the plant level and at the research level as a highly interactive system consisting of equipment, chemistry, and operational factors. A long history of plant tests has shown rather clearly that it is not very fruitful to work in any one of the factors without
Flotation Machines
Table of ContentsAir Lift Flotation MachinesSouthwestern Air-Lift MachineMatless Flotation MachineCallow-Maclntosh Machine Industrial flotation machines can be divided into four classes: mechanical pneumatic froth separation column air-lift matless As pneumatic and froth separation devices are not commonly used in industry today, no further discussion about them will be given in this module. The mechanical machine is dearly the most common type
Flotation Frothers – Frothing Agents
Table of ContentsFrothers behaves as SoapFrothing ReagentsSURFACE TENSIONCreating a Froth for FlotationTesting Frother Performance The next reagent that is added is the Flotation FROTHER. The frother strengthens the surface tension of the air that is injected into the flotation cell. As the air rises in the shape of bubbles, they come into contact with the mineral laden collector which attaches
Flotation Fundamentals
The separation of one component from another by flotation depends on the relative water-wetting ability of the surfaces of the various particle components. Many of the current chemical collectors in use are heteropolar, that is, they contain both a polar charged group and a non-polar uncharged group. When attached to a component surface, these surface active collector molecules are
Large Scale Flotation Plants
Although froth flotation was originally developed for mineral separations in the early 20th century, the use of this process has been extended in the last twenty years. From a processing viewpoint, all of these seemingly different industrial uses can be treated using the same theoretical concepts (including equipment and basic underlying chemical reagent structures) that have been developed in the
Mineral Processing Froth Flotation
Froth Flotation is a mineral processing process achieving solid-solid separation by taking profit of the chemical attribute leading to the possibility of selectively controlling the relative surface hydrophobicities of the various components mixed in an aqueous medium. Froth flotation is the most common industrial process based on this approach. The term surface hydrophobicity refers to the tendency of the particle
Exploration of Porphyry Copper Deposits
So how do we explore for Porphyry Copper Deposits which are completely covered by barren younger rocks? Well let’s back up a bit, we know that porphyries form under large subduction related volcanoes and that most of these are located under the ring of fire around the subducting pacific plate another fertile subduction zone occurs in Balkans, Turkey, Iran and
Ball Mill Critical Speed
A Ball Mill Critical Speed (actually ball, rod, AG or SAG) is the speed at which the centrifugal forces equal gravitational forces at the mill shell’s inside surface and no balls will fall from its position onto the shell. The imagery below helps explain what goes on inside a mill as speed varies. Use our online formula The mill speed is typically
Ball Mill Design/Power Calculation
The basic parameters used in ball mill design (power calculations), rod mill or any tumbling mill sizing are; material to be ground, characteristics, Bond Work Index, bulk density, specific density, desired mill tonnage capacity DTPH, operating % solids or pulp density, feed size as F80 and maximum ‘chunk size’, product size as P80 and maximum and finally the type of circuit open/closed you
Effect of Grinding Media Charge on Mill Power Draw kW
Maximum power is drawn by a mill when the charge occupies approximately 50% by volume. The power curve becomes very flat in the range above 45%. As a result, mills are seldom run with charge levels greater than 45%. In rod mills, the charge is swollen by particles of feed which separate the rods. If the mill is shut down immediately