How to Improve Ball Mill Grinding
Functional performance analysis of ball milling has been described previously by Mclvor. “Coarse” versus “fine” or product particle cut-off size is first selected, usually equal to some benchmark passing size of the circuit product (e.g., 80%). The function of the grinding circuit is to generate new product size material (or “fines”) from “coarse” particles in […]
How to Calculate Grinding Mill Operating Efficiency
In grinding, operating Efficiency compares the operating work index of a comminution machine to the Bond work index from bench scale crushing and grindability tests or/and pilot plant tests. Economic Efficiency is comparing the income from production to the planned income from production. Energy as consumed in comminution machines and the required energy as determined, […]
AG & SAG Mills Curved Pulp Lifters
Curved pulp lifters have been incorporated in SAG and AG mills in Australia. The aims have been to ensure complete discharge, at high throughput, of both slurry and coarse solids, especially at high mill rotational speeds. Curved pulp lifters can overcome incomplete discharge and back-flow of solids down the pulp lifter that can occur in […]
AG Autogenous Grinding Power Efficient
The importance of efficient use of power in autogenous grinding circuits has been greatly neglected. It should be the fundamental factor in considering the design of an autogenous plant to grind a particular ore. The steps in the process used to arrive at a power efficient commercial autogenous plant for a particular ore are outlined. Before […]
How to Reduce Steel Consumption in Grinding Mills
The fact that over 25% of the original weight of steel liners and balls is discarded as waste is probably one of the factors that has not been considered often. This is particularly true for mill liners, “Mill liners are finished metal products of some precision, they cost two to four times the basic cost […]
Grinding Circuit Modelling
Grinding Circuits Fine grinding is carried out in five primary circuits, six secondary circuits and one regrind circuit which grinds copper scavenger concentrates and copper cleaner tailings. A diagram of the primary and secondary grinding circuits showing sample points and their identification is given in Fig. 1. Mechanical details of the ball mills are listed […]
Rationed Ball Mill Charging to Improve Grinding Efficiency
Ball Sizes As mentioned earlier, years of operating experience indicated that the maximum ball size for the 2.93 m Climax mills was 76 mm. Application of Azzaroni’s equation confirmed that 76 mm was the correct maximum size. The selection of the second, smaller ball size was made by analyzing historical screen analyses representing composite ball […]
How to Control a SAG Grinding Mill Circuit
Autogenous and semi-autogenous grinding have experienced renewed interest as efforts to reduce operating and capital costs have increased. As a result, the mill operator is faced with new equipment perhaps ten times as large as was common in the sixties and new circuit designs with different operating characteristics. No longer can he grab a handful […]
Cone Crushing, Rod Milling and Ball Milling Laboratory Testing
The two largest cost components in comminution circuits are energy consumption and metal wear which, for cone crushing, rod milling and ball milling, can be established by conducting laboratory bench scale tests. Pilot plant testing for these comminution methods is not normally required. Laborary testwork performed by Allis-Chalmers to identify these parameters are covered by: […]
Autogenous Grinding & Semi Autogenous Grinding Circuits
Size reduction is the most expensive operation in most mills. Crushing and grinding usually require the greatest portion of capital costs and often make up 60-70 percent of total mill operating costs as shown in Figure 1. Selection of the proper crushing and grinding method must, therefore, be done with great care to be sure […]