Bowl Classifiers

The bowl classifier incorporates a two-stage baffled-return separating action, and it consists of a straight classifier with the usual reciprocating rakes, upon which is superimposed at the lower end a shallow circular bowl with a revolving rake mechanism. The general construction of the Dorr Bowl Classifier is shown in Fig. 20.

The feed enters at the centre of the bowl, and, falling on to a baffle-plate placed at the level of the surface of the pulp, is directed radially outwards. In passing from the centre to the periphery the coarser particles settle and only the fines overflow into the annular

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By | 2017-03-17T19:18:40+00:00 October 12th, 2016|Categories: Classification|Comments Off on Bowl Classifiers

Hydraulic Classifiers

Hydraulic classifiers range from simple V-shaped launders with a multiplicity of shallow settling pockets for the discharge of as many roughly sized products to the more elaborate deep-pocket machines of the hindered- settling type, having specially designed construction plates and automatic discharge of spigot products.

Dorrco Sizer

In the eight-pocket machine, the pockets are separated by 3-ft.-high partitions and increase in cross-sectional area from 1 sq. ft. in the feed end to 3.12 sq. ft. in pocket 8. The size of hole and hole spacing in the constriction plates depend upon the size distribution of the

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By | 2017-03-17T19:22:08+00:00 July 12th, 2016|Categories: Classification, Dewatering|Comments Off on Hydraulic Classifiers

Screw-Spiral Classifier: Select, Size & Install

The size of mechanical classifier required for a particular job depends on the following factors:

  1. Tons of dry solids to be overflowed per 24 hours. This is simply a predetermined tonnage.
  2. Mesh size at which separation is to be made. The mesh size is determined by laboratory tests or is already known from previous experience.
  3. Density desired in the overflow. This is dependent upon subsequent treatment.
  4. Settling rate of solids, of the size at which separation is desired, in pulp of the particular density of the proposed installation. This is determined by laboratory settling tests.

Overflow Capacity of the Mechanical Classifier

If the settling rate has been determined by laboratory tests the classifier pool area required is obtained from the following formula:

Effective pool area, sq. ft. = Vol. overflowing, cu. ft. per min/Settling rate, ft. per min.

This is the best method of determining the required pool area. However, if settling tests have not been made and it is inconvenient to make tests, the following procedure, which has been proved to be entirely satisfactory, may be used.


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By | 2017-03-17T19:23:48+00:00 June 1st, 2016|Categories: Classification, Equipment|Tags: , , , |Comments Off on Screw-Spiral Classifier: Select, Size & Install


Hydroclassifiers are solving the most difficult fine sizing and desliming problems by combining high metallurgical efficiency in a rugged, well- built machine to accurately fulfill the exacting conditions required. Accurate separations can now be made in the 100 mesh range and finer. This fine separation requires considerable classification area per ton as well as minimum agitation and accurate control.

New processes in the flotation, cyanidation, chemical, and industrial field are now opened up by this new machine. Definite applications include elimination of slime from breaker sludge in the

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By | 2017-03-17T19:23:49+00:00 June 1st, 2016|Categories: Classification, Dewatering, Equipment|Tags: , |Comments Off on Hydroclassifier

Flash Flotation with Closed Circuit Grinding

The reason why you need Flash Flotation in a Closed Grinding Circuit relates to “Recovering your mineral as soon as free” which has long been recognized in ore dressing practice. This not only applies to gravity treatment but also to flotation. For this application the Flash Flotation Cell was developed for use in the grinding circuit and has done a remarkable job in many plants.

Flash Flotation with Closed Circuit Grinding 4 Options for Flash Flotation in a Closed Circuit Grinding Plant

A greater amount of granular higher grade concentrates can be produced and, in general, overall plant recovery is improved by reducing slime

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By | 2017-03-17T19:28:01+00:00 April 14th, 2016|Categories: Ball Mills, Classification, Flotation, Flowsheets & Flowcharts, Grinding|Comments Off on Flash Flotation with Closed Circuit Grinding

Grinding and Classification Circuit

Our EXAMPLE Grinding and Classification Circuit is designed to grind 500 tonnes of ore per day, operating 24 hours per day, with an availability of 95%.  This circuit will grind -5/8″ material from the Crushing Plant, classify the slurry in one of two cyclones, and pass 70% of the minus 200 mesh material to the mill feed Thickener Circuit at a rate of 22 mtph.
This section is intended to be read in conjunction with the Flowsheet and Piping and Instrument Diagrams.

The Grinding and Classification Circuit is designed to the following criteria:

F80 Feed Size 80% minus 7/16&#8243

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By | 2017-03-19T05:56:55+00:00 February 1st, 2016|Categories: Classification, Concentrator Manuals/Procedures, Flowsheets & Flowcharts, Grinding, HydroCyclones, Pumps and Pumping|Tags: |Comments Off on Grinding and Classification Circuit

How to Improve Cyclone Separation

Good cyclone separation depends upon control of pressure drop, pulp density and apex size. The ‘pressure drop’ may vary but should not change rapidly, and is held at safe levels by keeping an adequate sump level. A falling sump level causes cavitation in the pump and reduction in feed rate; pressure drop in the cyclone falls and solids report increasingly to the overflow until

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By | 2017-03-19T06:33:10+00:00 January 10th, 2016|Categories: Classification, HydroCyclones, Tools of a Metallurgist|Comments Off on How to Improve Cyclone Separation

Solvent Extraction & Electrowinning (SX/EW) Plant Design

SX-EWCerro Verde began operations in April 1977, originally formed and operated by Minero Peru, as a state-run mining company. The electrowinning tankhouse was designed to produce 33,000 metric tonnes per year (mtpy) of copper cathode operating with current density of 184 amps per square meter (A/m2) and 88 percent (%) electrical current efficiency. In 1994 the mine was privatized and purchased by Cyprus Amax, which undertook an expansion project to expand cathode production to 48,000 tonnes per year using a current

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By | 2017-03-26T08:31:50+00:00 November 8th, 2015|Categories: Classification|Comments Off on Solvent Extraction & Electrowinning (SX/EW) Plant Design