Instructions for use of rod mill and configuration of steel rod diameter

Instructions for use of rod mill and configuration of steel rod diameter

Diameter configuration of steel bar in rod mill

The diameter of the steel bar should be selected properly, which can not only break the large block, but also have enough surface to accumulate. The steel bar with small diameter has larger surface area and smaller wear to lining plate. However, the selling price of small-diameter steel bars per unit weight is high and their service life is short, because the small-diameter steel bars are quickly worn to the abandoned size of 25-40mm. When the steel bar is worn to this size, it is easy to break and bend.

When the maximum diameter of the steel bar is 100-115mm, the steel bar is often broken when it is worn to 38mm. The broken steel bar can be discharged out of the machine during operation. When the maximum diameter of the steel bar is only 50-65mm, the worn steel bar is easy to bend. During operation, the steel bar smaller than the scrap diameter should be taken out regularly. The diameter of commonly used steel bar is 50-100mm.

(2) length configuration of steel rod of rod mill

The length of the steel bar is the effective cylinder length (i.e. the net length of the length of the cylinder minus the thickness of the end cover liner) minus 150 mm (or 300-400 mm from the nominal cylinder length).

(3) ratio of steel bar load size of rod mill

The size matching method of the first installed steel bar load is similar to that of the ball size in the ball mill

There are three purposes of rod mill:

1) in order to prevent the harm caused by over grinding, rod mill is often used in gravity concentration or magnetic separation plants of tungsten tin ore and other rare metal ore;

2) when the second grinding process is used, if the first grinding is from 20-6 mm to 3-1 mm, the rod mill is used as the first grinding equipment, the production capacity is large and the efficiency is high. Because the surface area of a certain weight of rod load is much smaller than that of the same weight of ball load, the productivity and efficiency of rod mill are lower than that of ball mill in the second stage of fine grinding;

3) in some cases, it can be used as fine crushing instead of short head cone crusher. When processing soft or not too hard ore (especially the ore with large viscosity) and grinding 19-25 mm (or even 32 mm) ore to 6-10 mesh with rod mill, the configuration is simpler and the cost is lower than that when using short head cone crusher and screen to form a closed circuit, and it can simplify the dust removal in the crushing workshop. For hard ore, it may be more economical to use a short head cone crusher to form a closed circuit with a sieve. In the design of ball mill or rod mill, it is necessary to make a plan and compare it according to the specific situation.

Rod mill is widely used in metal and nonmetal mines, water conservancy and building materials departments to grind various ores or rocks.

Rod mill is decelerated by motor through reducer and surrounding big gear or directly decelerated by low-speed synchronous motor through surrounding big gear to drive cylinder to rotate. The proper grinding medium steel bar is installed in the barrel. Under the action of centrifugal force and friction force, the grinding medium is lifted to a certain height and dropped or discharged. The milled material enters into the cylinder body continuously from the ore feeding port, is crushed by the moving grinding medium, and discharges the product out of the machine through overflow and continuous ore feeding force, so as to carry out the next process.