The ball mill can be operated in one of two ways, either with open or closed circuit conditions. In open circuit grinding, the feed material passes through the mill just once and all the particles are ground to the maximum required size. In closed circuit grinding the mill operates in conjunction with the air separator which classifies the ground particles, over size material being re-circulated as part of the feed. The feed to a closed circuit mill is subsequently larger in quantity than to an open circuit mill and the re-circulating load is fed to the mill at the rate of 200 to 300% feed.
One of the main principle of ball milling is to present the material being ground with the correct size of ball for most efficient grinding. The larger the particle size and harder or more tougher to grind the material, then the larger the ball required to crush that particle. The smaller the particle size to be produced, then the smaller the grinding ball necessary to generate the new surface area required.
In conventional mill practice, this is achieved by splitting the mill into at least three chambers, each one being separated by a diaphragm. It is possible to automatically classify different sizes of balls along the length of the tube mill by specially designed shell lining plates which are contoured axially as well as radially.
This classification is achieved by the rebound action and the differential momentum of different size of balls. It is essential to obtain the correct cascading action within the charge for classification to occur. For this reason, volume loading must be carefully controlled since if the mill is too full , the correct action will not be generated with the charge and classification will not occur.
A recent development in the field of grinding technology has been the introduction of minipebs grinding systems which enables the fine grinding of super rapid hardening cements in open circuit. This system utilizes extremely small cylpebs weighing only ½ grams.
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Grinding practice: ball mill, cement mill
The ball mill can be operated in one of two ways, either with open or closed circuit conditions. In open circuit grinding, the feed material passes through the mill just once and all the particles are ground to the maximum required size. In closed circuit grinding the mill operates in conjunction with the air separator which classifies the ground particles, over size material being re-circulated as part of the feed. The feed to a closed circuit mill is subsequently larger in quantity than to an open circuit mill and the re-circulating load is fed to the mill at the rate of 200 to 300% feed.
One of the main principle of ball milling is to present the material being ground with the correct size of ball for most efficient grinding. The larger the particle size and harder or more tougher to grind the material, then the larger the ball required to crush that particle. The smaller the particle size to be produced, then the smaller the grinding ball necessary to generate the new surface area required.
In conventional mill practice, this is achieved by splitting the mill into at least three chambers, each one being separated by a diaphragm. It is possible to automatically classify different sizes of balls along the length of the tube mill by specially designed shell lining plates which are contoured axially as well as radially.
This classification is achieved by the rebound action and the differential momentum of different size of balls. It is essential to obtain the correct cascading action within the charge for classification to occur. For this reason, volume loading must be carefully controlled since if the mill is too full , the correct action will not be generated with the charge and classification will not occur.
A recent development in the field of grinding technology has been the introduction of minipebs grinding systems which enables the fine grinding of super rapid hardening cements in open circuit. This system utilizes extremely small cylpebs weighing only ½ grams.