Case Studies

Review the necessity of pre-desliming in coal washing plant?

Because of the breakthrough of coal washing technology in non-desliming heavy medium cyclone, it makes the advantages of the ancient technique of desliming before separation only the lower requirements for the system designers. As far as the precision of separation is sacrificed to reduce a little medium consumption, it should be a shortcoming, otherwise, it will be replaced with water. I have dealt with this in previous relevant articles, and I would like to highlight only a few points as follow:

1, The "regulation of solid volume concentration in working suspensions should not exceed 35%" is already broken through (such as super heavy medium cyclone). And the specific data is technical secret which can not be disclosed. Now we only talk about the basic principles. The shear force in the cyclone can destroy the structural viscosity of the slurry. Therefore, increasing the shear force can increase the allowable volume concentration and increase the amount of treatment.

2, The amount of slime in the circulating slurry only needs to be controlled in the appropriate range. It can not, nor do they need to be fixed, at all, unlike this article: "in actual production,... the amount of slime is a fixed value.” 

3, Fine coal, especially difficult separation coal, can only be separated by inefficient water medium. This will, as this article says, "certainly lead to a certain economic loss."

4, The new technology of preparation of non-deslimed raw coal requires high level of system design, not operation level. As far as the heavy medium system is concerned, it is indeed easier to operate and manage the coal preparation plant with deliming technology, especially when the system design is poor. But in any case, it can't be said that the car is not good because a jinricksha is easier to design and operate than a car. In China, there is no reliable data to prove that the desliming ratio is advanced than non-desliming. In the coal preparation plant without pre desliming process, the medium consumption is low. Why?

The simple explanation is:

There is no necessary connection between the high or low medium consumption and the desliming or non-desliming.

As long as the coal preparation plant pays attention to the selection of sufficient number of magnetic separators and sufficient depth clarification of circulating water, the recovery of water spray medium is good enough. As long as we do the above three aspects, the consumption will be low. Therefore, HOT began to doubt that the medium consumption of desliming is lower than non-desliming. The idea is correct because desliming or non-desliming is not the main factor in medium consumption.

作者:

Author: Steven Heng Huang

MAusIMM, Competent Person (JORC)

Mining Engineer & Metallurgist

More details about coal washing technology, pls contact me:

kira.zhang@hot-mining.com

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