Category:Models

Models

This are two principal types of models in SAGMILLING.COM:

• Specific energy consumption models are used to estimate the amount of grinding energy required to grind a particular ore, and what throughput can be achieved by passing that ore through a particular set of grinding mills.
• Mill power draw models are used to estimate how much grinding energy can be generated by a particular mill geometry and charge.

Theory of Power Models

A relationship between energy consumed in grinding and size reduction was proposed by von Rittinger in 1867, yielding the first Power Model and beginning of comminution as a science ^{Lynch & Rowland, 2005}.

Authors such as Taggart and Bond noted several properties of common size reduction processes that allows modelling as a process of energy consumption by and ore^1,2. The underlying observations (and assumptions) of Power Models are:

• Any particle size distribution can be modelled by a single value. Generally, it is the 80% passing size that is used as being indicative of the entire size distribution.
• Particle size distributions of "normal" size reduction processes

In general, the mill power draw models are independent of the ore being processed (ore density matters, but feed and product sizes should not affect power draw if the mill is run properly). The specific energy model uses the ore grindability test results to estimate energy requirements to achieve a particular size reduction, then it calls on the mill power draw model to determine how much energy is actually available. Dividing the energy available by the specific energy consumption results in the throughput.