Grade Recovery Curves for Mineral Beneficiation

To characterize the flotation step in the beneficiation of a mineral ore, it is necessary to postulate that the mixture consists of at least two distinct particle populations, one largely valuable and the other principally waste (gangue). The gangue will invariably consist of several different mineral types, the presence of each being undesirable in the valuable mineral. Each population is characterized by a size distribution, and the amount of undesired material it contains. The fraction of misplaced material in a particular population can almost invariably be reduced by a sequence of size reducing steps usually consisting of primary and secondary crushing followed by fine grinding.

Increasing the fineness of grinding is said to liberate the valuable species from its associated waste component. This will result in increasing the fraction of the desired component in the valuable mineral recovered and reducing its amount in the gangue. While liberation of the valuable component is clearly desirable, overgrinding will increase the power consumption of the mills, and as observed by Klimpel, also possibly introducing difficulties into the flotation process and subsequent downstream processing.

It is important to have a measure of the effectiveness of separation before an optimal solution can be identified. From a systems viewpoint, the flotation operation in mineral processing will separate a feed stream, F, into two product streams, a concentrate stream, C, containing an increased fraction of the valuable component and a tailings stream, T, containing a reduced amount of the valuable component. The following overall mass balance will apply:

where Xp, %Q and xT are the mass fractions of the valuable component in the feed, concentrate and tailings, respectively. The performance measurement is characterized by two parameters. The fractional recovery R of the valuable component in the concentrate:

Cxc FxF

and its purity (grade) in the concentrate stream. The grade may simply be the mass fraction xC or can be normalized between 0 and 1:

froth. The optimal performance of the flotation operation is defined in terms of the minimum cost of achieving a particular grade-recovery target.

Solar Panel Basics

Solar Panel Basics

Global warming is a huge problem which will significantly affect every country in the world. Many people all over the world are trying to do whatever they can to help combat the effects of global warming. One of the ways that people can fight global warming is to reduce their dependence on non-renewable energy sources like oil and petroleum based products.

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