There are basically two groups of Grinding Mill Liners. Ones with a HIGH PROFILE and those with a LOW PROFILE. The high profile liner is designed to give the media the higher lift. This type will be used in mills that are designed for primary grinding and as a result require the impact of the … Read more
I am going to discuss only one more variable that has to do with grinding media and that is CRITICAL SPEED of Tumbling Mills. The throughput of a mill may be increased by increasing the revolutions per minute of the mill. This will give the ore the necessary increase of available media surface needed to accomplish the … Read more
The third type of mill that I mentioned was an AUTOGENOUS MILL, this type of mill uses a completely different type of grinding media; the rock itself In conventional milling, the ore is crushed to, plus or minus, 3/8 of an inch, before it is put into a mill for grinding. In a autogenous mill … Read more
Among the cast materials used for linings are Ni-Hard. chrome-molybdenum steel, and manganese steel. Rolled alloy steel plate with lifter bars is available Rod mill liners are subjected to severe impact. Premature breakage and scrap loss are reduced by correct selection of liners for the specific gnnd-mg duty. Additional benefit results from use of a backing … Read more
Density, if you recall is the ratio of ore to water and is measured as a percent of solids in the water. It will control the grind in two ways. It affects retention time and helps distribute the ore through-the mill so each piece of rock will come in contact with the surface of the … Read more
Before doing multiple laboratory flotation bench tests in which you need P80 grind controlled or predicted, you need to build a Grind Calibration curve following this short procedure. You will consistently add sufficient water to the mill to achieve a pulp density of 67% solids (Example: 1 kg solids + 0.5 kg water or 2 kg … Read more
In an effort to evaluate the metallurgical results of an operating plant, 3 process stream samples (red points) provided were subjected to detailed modal analysis using protocols established for mineralogically similar ores. This method of analysis provides quantitative estimates of the mineral composition and of the mineral fragmentation characteristics. This data can then be used to … Read more
The single most common reason for an increase or drop in the production of fines is the WORK INDEX of the ore. If you remember, the work index of the ore is a method of measuring the degree of hardness. As the ore becomes harder the fracture lines in the rock become cleaner or sharper … Read more
One area of major importance for the identification of impending problems are the feed belts. By visually estimating the PHYSICAL CHARACTERISTICS of the ore it is possible to have advance warning of change in many of the variables. Feed size is the most apparent, if the crush is supposed to be minus 3/8 of an … Read more
What I would like to do now is expand upon the grinding theory involved. Bring all of the earlier information together and show you how it relates to the operation of a mill and make you capable of Operating a Grinding Circuit correctly. Then I will explain the differences between Rod mills, Ball mills, SAG … Read more