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. […]
Structural Analysis of Grinding Mill Shells
Accurate modeling of structures by finite elements requires not only that the user estimate the load paths, and areas of stress concentrations or rapid variations, in a structure, but also that he realize the modeling idiosyncracies of each element he is working with. He needs to know limitations in displacement function assumptions, aspect ratios, angles, […]
Slurry Flow Rate Through a Mill
The factors upon which the rate of flow of the pulp through a mill depends appear not to have received extensive investigation. In an article by Anselm translated by Pearson a method for the calculation of the time of passage of cement through a ball mill was given. The basis of the method is that the […]
Grinding Mill Surging
The phenomenon of “surging” in a mill is a subject upon which very little has been written; presumably because it is a condition which cannot be tolerated in mill operation and which must be eliminated by variation of some or many of the physical dimensions or characteristics of the mill or mill charge. The phenomenon known […]
Effect of Grinding Media on Milling
In the previous chapter the influence of the various physical quantities defining the mill and mill charge has been studied in connection with the performance of a mill as a device for the creation of new surface in the powder. For some purposes, however, it is also desirable that the product should have a preferred […]
Effect of Pulp Rheology on Grinding Mill Power
The dependence of the power demand of a mill on the nature of the pulp does not appear to have received a great deal of study, and, in general, observations on this matter take the form of general statements. For example, Taggart states that, other things being equal, wet milling requires 60-90 % of the power […]
Wet VS Dry Particle Size Analysis
The analysis of particle size distributions has become increasingly important in industrial processes. Particle size is recognized to be fundamental to the control of operations as diverse as grinding, crystallization, emulsification, agglomeration, and more. Particle size determination has traditionally been relegated to the laboratory, and is performed by slow, labor-intensive methods such as sieving, sedimentation […]
Temporary Emergency Replacement Mill Liners
Shell liners wear very fast in very large diameter autogenous and semi-autogenous mills. In addition to shell liner wear, the ends of the mill are susceptible to very high rates of wear, generally confined to fairly narrow bands. Due to the sheer size of modern mills, extensive downtime is required to replace shell liners or […]