Variables Affecting Grinding Mill Power
The study of grinding is a study of cause and effect. The pre-ponderance of the literature is on the latter—effect. It seems that the study began at the end, with effect, and worked backward without going back far enough to reach the cause. The cause is energy input. In this paper it is paramount and […]
Effect of Grinding Media Density on Power & Grind
In table 3 of a recent publication a report was made on the use of pipes (instead of rods) stuffed with different materials to give grinding media of different densities when the dimensions were always the same. The mill had a large discharge opening. There it was shown that through a range of densities from […]
Effect of Pulp Density on Grinding
Batch Mill Grinding of Ore Batch grinding affords the best opportunity for first studies of pulp consistency. Table 6 shows some of the results. The consistencies ranged from 80 to 20 percent solids. The initial five tests will be considered first and the last one will be mentioned later. In the last test of the series […]
Effect of RPM Rod Mill Speeds
In a study of rod-mill discharge openings of different sizes, four pairs of tests were made at speeds of 40, 50, 60, and 70 percent of critical. In each pair the discharge openings were 8.0 and 4.5 inches, respectively. The tests were conducted so that the tons per horsepower-hour were nearly the same. This manner […]
Ball Mills vs Rod Mills
When the mill is rotated without feed or with very fine feed, the rods are in parallel alignment and in contact with one another for their full length. New feed entering at one end of the mill causes the rod charge to spread at that end. This produces a series of wedge shaped slots tapering […]
Wet Grinding VS Dry Ball Mill Grinding
Batch Ball Mill Grinding Capacities and efficiencies in wet and dry ball milling at different speeds and ore charges have been discussed in the foregoing pages. The results are summarized in table 16, which shows that in both capacity and efficiency grinding was at its best with small ore charges and high speed. Likewise, in […]
Batch Ball Mill Grinding
Chert, which is very hard, and dolomite, which is moderately hard, were selected for use in a study of the effect of different speeds and ore charges in batch tests. Mill, ball load, and pulp consistency always were the same. Results for chert are shown in the upper section of table 13, and for dolomite […]
Batch Mill Grinding VS Continuous Grinding Compared
When the amount of ore in the mills was the same, no appreciable difference between batch and continuous open-circuit ball-mill grinding was found. This should be so, because the progression in particle size for the duration of a batch run would be expected to be the same as the progression from the feed to the […]
Concentrate Regrind
We used the original flowsheet for two and a half years and made concentrates containing 16%-18% insol. Then we were asked to reduce the insol content as much as possible without additional capital expenditures in an effort to improve the smelting process. One of the 7 x 10 bail mills had been outfitted with four […]
Attrition Grinding Mill Design
As part of its mission to advance minerals technology, the Federal Bureau of Mines has conducted investigations to determine the feasibility of producing subsieve-size material by an attrition grinding method. The Bureau-patented technique involves the intense agitation of a slurry composed of the material to be ground, a granular grinding medium, and a suspending fluid. […]