Cement is a construction staple which is always present when any structure is being erected. The basic ingredients of cement include calcium, silicon, iron and several others which can be obtained from limestone, aragonite, and other natural resources. Generally, the most common raw material sourced from cement is limestone.
There are several processes involved in cement production. The first step after collecting the raw material from the quarry site is to prepare the materials for further use. Usually, limestone is obtained in large boulders which need to be broken down or crushed into smaller pieces before it is mixed with other raw materials. Limestone is crushed using either a limestone ball mill or a limestone Raymond mill. While they both do essentially the same work, they are different in several ways.
Differences in Applications
Ball mill for limestone is more common with mining activities for minerals such as iron ore. This type of mill is used to prepare raw materials before smelting; it is, therefore, usually used for beneficiation activities at mineral processing plants. Other plants that employ ball mill grinding include cement plants, glass plants, and refractory plant.
This mill makes use of energy conserving balls that helps to save about 30% energy through its overflow discharge, compared to other conventional mills. Ball mill for limestone is used not only for mining and plants but also in the construction and chemical industry. Although, it is used mainly for processing the iron ore needed by these industries.
Grinding of materials using this mill could be through either of two grinding methods: dry and wet methods. The wet grinding method is used when the material contains high moisture, while the dry grinding method is used when raw material has no moisture. Each of the two grinding methods has two types of discharge: lattice discharge and overflow discharge. Lattice discharge consumes more energy while overflow discharge conserves energy.
Raymond mill for limestone, on the other hand, is more common with the production of sand and gravel. It is used by plants that produce marble, cement or insulation materials. Other materials for which Raymond mill can be used for, include feldspar, marble, talc, fluorite, clay, carbon, kaolin, rock, calcite, and nearly 300 other materials.
It can also be applied to moderately hard insulation materials, chemical, fine powder with less than 6% moisture content, and other construction materials. A material as large as 600 mesh can be crushed to about 80 mesh using the R-type of Raymond mill.
Differences in Working Principles
Ball mill for limestone is a horizontal rotating machine in a cylindrical shape. The material is fed into the chamber through an air shaft after it has been previously homogenized at the warehouse. The steel balls that do the crushing are powered by a centrifugal force produced by the rotating part of the ball mill. This centrifugal force pushes the balls to the height required for them to function.
To intensify the impact of the balls on the raw materials, they are fed from a height to make them fall on the balls. This is why you find ladders or corrugated liners in a ball mill for limestone plant.
The mill has several compartments. The first compartment houses the materials after its impact on the balls. Here, the material is still coarse. It is then sent to the second compartment where it is ground to a fine powder before being discharged through the grate plate.
Raymond mill for limestone works differently from a ball mill. Raw materials are fed into a Raymond mill using a feed hopper located at its side. The Raymond mill has a vertical axis that moves in a circular motion. The vertical axis is powered by centrifugal force from an outside rolling swing, which forces the axis to press on the grinding ring. This means that as raw materials are fed into the mill, they get between the rolling vertical axis and the grinding ring, two of which are pressed together by the centrifugal force. This impact causes the raw materials to be crushed.
Differences in Structure
BALL MILL FOR LIMESTONE consists of various components such as the feeding part, the grinding chamber, the discharge port, the cabin or control area, and several others. The lining is easily removable for maintenance purposes while its cylindrical chamber is lined on the inside to prevent rust and wear. The Mill’s hollow shaft is fitted with rust and wear with steel.
Raymond mill for limestone, on the other hand, consists of just the chamber, blower, cyclone and windpipe. Other components include grinding ring, inlet volute, and installation components.
Differences in Output, Fineness, and Cost
BALL MILL FOR LIMESTONE produces about 200 tonnes per hour while Raymond mill produces about 30 tonnes per hour.
Raymond mills produce finer output compared to ball mills.
Raymond mills also cost less compared to ball mills to set up and operate.
It would be best to keep all these differences in mind while choosing the best type of mill for your needs.