Rod Mill sand making machine
Rod mill sand making machine is a kind of reliable crushing machines widely used for making sand for building. Our rod mill sand making machine can be used to process or crush feldspar, quartz and ore. It can also suitable for fine and medium crushing of hard and brittle materials, such as abrasive material, fireproofing material, concrete, steel shot, copper ore, iron ore , gold ore, concrete aggregate, asphalt aggregate, etc. In addition, our sand making machine is especially suitable for crushing river gravel to make sand. It’s a kind of effective and energy saving sand making machine which can save more energy (50%) than traditional sand making machines.
Rod Mill Sand Making Machine Working Principle:
The barrel of rod mill sand making machine rotates at a certain speed. Under the influence of friction force and centrifugal force, grinding medium rises to a certain height and is thrown down. During the process, materials are impacted and grinded.
Rod Mill Functions:
1. Rod mill sand making machine is widely used in mining , water conservancy project and building materials processing.
2. The gearing down of reducer and gearwheel (driven by motor) or the gearing down of gearwheel (driven by low speed synchronous motor) drive the barrel of rod mill sand making machine to rotate.
under the driven force produced by motor or low speed synchronous motor’s reduction drive.
3. Under the influence of friction force and centrifugal force, grinding medium (steel bar) inside the barrel rises to a certain height and is thrown down.
4. Materials enter into the barrel continuously and are crushed by the movable grinding media. They are discharged under the force of overflow and continuous feeding.
Rod mills are very similar to ball mills, except they use long rods for grinding media. The rods grind the ore by tumbling within the the mill, similar to the grinding balls in a ball mill . To prevent the conditions leading to rod charge tangling, the length to diameter ratio is maintained at 1.4 to 1.6. Rod mills accept feed up to about 50 mm (2 in.) and produce a product in the size range of 3000 to 270 mm (–4 to –35 mesh). Grinding action is by line contact between the rods extending the length of the mill. Rods tumble and spin in roughly parallel alignment simulating a series of roll crushers . This results in preferential grinding of coarse material and minimizes production of slimes.
Of the three main types of rod mill, overflow, end peripheral discharge, and center peripheral discharge only the overflow mill is in common usage. Wet grinding rod mills are normally used in the mineral processing industry. Dry grinding is used in some areas; however, it is confronted with problems and should be avoided except where absolutely necessary.
Rod mills operate at lower speed than ball mills since the rods are rolled and not cascaded. For an equivalent grind, a rod mill uses less steel than a ball mill because of the lower speed and better contact between the media and ore. The rod charge must be maintained in good working condition, and broken and worn rods must be removed. Rod mills usually require greater operator attention. It is important that the rods stay essentially parallel to one another. If rods become misaligned, grinding action is lost and, more importantly, rod tangles occur. Maximum rod length is limited to about 6.1 m (20 ft). This in turn limits the length, diameter, and capacity of rod mills. The heavier rods acting upon the lifters and liners result in greater wear on the mill liners.
Rod mills normally carry 35 to 65% rod charge by volume. The limits on charge level are (1) keeping the feed end trunnion open so that feed will get into the mill, and (2) keeping the rod charge low so rods will not work their way into discharge openings where they can cause rod tangling.