Classification

Screw Classifiers

Rake Classifier

To be successful in a obtaining a uniform grind that is necessary to achieve a high percentage of recovery it is necessary to control the degree of fineness that the ore is reduced to. This is done by separating the fine material from the course and regrinding the coarse until it is fine enough for … Read more

Hydrocyclone Operation

hydrocyclone

The hydrocyclone operation consist of having the ore slurry pumped into its feed inlet, the ore is then separated by size with the fine material coming out of what is referred to as the “OVERFLOW” via a Vortex Finder. The mineral that still requires grinding is named the “UNDERFLOW” via the Apex Finder. These two … Read more

Overflow VS Grate Discharge Ball or Mill – Why Retrofit

Compare Overflow VS Grate Discharge Ball Mill

Allow me to compare: Ball mills can be of the overflow or of the grate discharge type. Overflow discharge mills are used when a product with high specific surface is wanted, without any respect to the particle size distribution curve.  Overflow discharge mills give a final product in an open circuit. Grate discharge mills are used when the … Read more

Principle of Operation of Hydrocyclone

What does a cyclone do

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 … Read more

Roping HydroCyclone -Bad Operation

HydroCyclone Roping – Incorrect Cyclone Operation is often caused by too high a volume feeding into the cyclone. If the apex capacity is exceeded a condition known as roping may occur. Normally, the underflow sprays out of the apex. When roping occurs, the air core inside the apex collapses and the spiraling motion is almost lost. … Read more

Hydrocyclone Efficiency Curves

real ideal hydrocyclone classification

The Hydrocyclone Efficiency Curves are affected by many operating factors such as feed density, apex and vortex sizes and feed pump pressure.  These factors will cause your cyclone classification to operate correctly, in roping or spraying mode.  Everyone knows or has seen an “Ideal Cyclone Efficiency Curve” VS an actual real life hydrocyclone Efficiency Curves?  I … Read more

SAG Mill Trommel Screen

Mill Trommels

A SAG Mill trommel screen lets you control the true discharge size of your SAG mill or the transfer size to the downstream Ball Mill circuit. A well sized trommel should not let rocks pass to the Ball Mill if they are to be more than say 5/8″ or 16mm In the image case below, strangely … Read more

How to Interpret Particle Size Distribution Data

D50 interpret particle size distribution data

For a great presentation on How to Interpret Particle Size Distribution Data D50 D80 D90 and D10 you need to see https://www.brainshark.com/malvern/particlesize_mining_mineral/z8azT04z0z0?v=3 by Malvern.

How to Size a Cyclone | Hydrocyclone

Hydrocyclone

How to Size a Cyclone or Hydrocyclone has a well establish step-by-step process for which Richard A. Arterburn was a pioneer.  Since this paper and its hydrocyclone sizing method is becoming hard to find, I uploaded it on here. Use the 911Metallurgist Online Cyclone Design Calculator. Hydrocyclone Design & Sizing Parameters – Calculations & Equations I … Read more