Hello Banyechan,

The reason for High chrome grinding media is simply one of economics, over all it has been proven that it improves recovery levels.

Check the attached PDF file for some more in depth information regarding this from

http://www.saimm.co.za/Conferences/Pt2010/399-404_Greet.pdf

Cheers,

Wayne

A study has investigated the effect of using different milling media on the ultimate flotation performance of a UG2 ore milled in a laboratory tumbling mill. The results showed that the different media required different energy inputs to obtain the same grind. They also resulted in different chemical conditions in the mill product in terms of parameters such as pH, Eh, DO and relative viscosities.

Flotation tests were carried out on each mill product in order to investigate whether using different media significantly affected the recoveries and grades of the PGMs and the chromite since these are key factors in the treatment of such ores. Using stainless steel (SS and SS+CS) and ceramic (CE) media resulted in higher Eh and DO values compared to the use of forged steel (FS) and 15% chrome steel (CS).

The five different media produced virtually the same solids and water recovery. There were however significant differences in the recoveries and grades of the PGMs (as indicated by PGE assays) and of chromite. Grinding the ore using ceramic media produced the highest PGE recoveries and the lowest Cr2O3 recovery while the grades and recoveries after using stainless steel (SS) were the lowest in the case of PGEs and the highest in the case of Cr2O3. The possible effect of galvanic interactions on these results has been proposed to contribute to the differences observed. Stainless steel produced higher fines content and this may explain the higher chromite recovery. Using ceramic media also required the least amount of specific energy to achieve a grind of P80 < 75 µm.

SEE PAPER