Grinding & Classification Circuits

Grinding & Classification Circuits

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The function of Hydrocyclones in a closed milling circuit wrt to the required grind (1 reply)

R
richardh
6 years ago
richardh 6 years ago

Hi

I am trying to build up a library of papers on the function of a hydrocyclone in a closed ball mill circuit and not as a means 'of doing any grinding'. I am often faced with the question "We have a grind of 'A' micron in our ball mill circuits but wish the cyclones to cut finer achieve a finer grind of 'B' micron."

And on the rare occasion where the ore characteristics and mill power etc allow, they ask for the reverse.

Simplistically the function of the mill is to do the grind and the classification device, in this case is to match the required grind and to give the required circulating load required by that circuit and to classify as efficiently as possible. The cyclone shouldn't be used to try control the grind and by changing the cyclone parameters you will alter the recirculating load, thus also affecting the cyclone efficiency etc.

A search revealed this web blog:  https://orway.com.au/uncategorized/cyclones-dont-grinding/

Are you aware of any similar

b
Robert
6 years ago
Robert 6 years ago
Like
1 like by David

Not knowing your situation re accessing technical literature?

For some additional details look at:

Seitz, R.A. and Kawatra, S.K., Further studies on the use of classifiers for the control of wet grinding circuits, Int. J. Mineral Process., vol. 12, 1984.

http://www.sciencedirect.com/science/article/pii/0301751684900310

The use of inferential particle sizing for wet grinding circuit control is well established in the literature. In this paper an analytical development is presented which yields a general inferential sizing model relating circuit product size to d50(corrected) for the circuits' classifier. It is then shown how the different forms of empirical equations reported in the literature can arise, depending on the range of the operating variables and the ratio of feed 50% passing size to d50(corrected). Following this development, data show pilot plant and industrial plant operations to behave as predicted by the general inferential size model.

 

Hukki, R.T., Fundamentals of the closed grinding circuit, e&mj, April, 1979, 102-109.

Most mill operators are confronted with the same basic problems in the grinding cycle: how to grind the largest possible tonnage to a given specification using the least amount of energy and creating the smallest possible percentage of extreme fines. This article addresses these problems as a function of the relationships between the major grinding variables - circulating load, sharpness of size separation, new feed rate, grinding time, energy consumption, and others. Optimum and average conditions for the production of a final fine product are discussed, and the importance of using a two-stage classification system to improve the sharpness of size separation is reviewed. Research into the relationships of grinding variables is summarized, along with graphical and mathematical means for calculating some of these variables.

 

Hukki, R.T. and Allenius, H., A quantitative investigation of the closed grinding circuit, Trans. SME-AIME, vol. 241, 482-487.

This paper describes in quantitative terms the effect of sharpness of classification on the performance of the closed grinding circuit. The analysis is based on a large number of laboratory experiments designed to simulate the two most common industrial closed grinding systems. The experimental results show quantitatively the degree of improvement achievable by more efficient classification.

 

Also look at:

https://www.911metallurgist.com/grinding/high-recirculating-loads-in-ball-mill-circuits/

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