IM 2018 May 18 | Page 43

PRECONCENTRATION

have sufficient area to recover 95 % of the medium being fed to it, and that allowance must be made for potential blinding which will reduce the open area of the screen.

“ It is vital to take the average particle size and bed depth into account when selecting the screen width,” she argues.“ Running at too high a bed depth will increase medium carry-over from the drain to the rinse section, and will also reduce the efficiency of the rinse water in washing off the medium; this in turn will lead to an increase in magnetite losses.”

Another important aspect to observe is that sufficient rinse water must be used to wash off the adhering medium, without overloading the wet drum magnetic separators. Provision must also be made at the end of the screen – after rinsing – for the clean coal and reject material to dewater before being discharged off the end of the screen, says Schoepflin.

The AKA-FLOW gravimetric sorting solution

AKW Equipment + Process Design offers solutions for the wet mechanical processing and environmental technologies. One option for reducing wastewater in the treatment process is to reduce the amount of material to be processed. In the last ten years AKW Equipment + Process Design has developed and marketing the dry gravity separator AKA-FLOW. There are

The AKA-FLOW can help mines reduce wastewater by reducing the amount of material to be processed

two models, the AF04 capacity 6 t / h and the AF12 at 9-18 t / h. Both can handle grain sizes from 30 μm to 2 mm.

“ The AKA-FLOW is a dry working gravimetric sorting device and used for preliminary separation and enrichment of materials of different densities as a possible pre-stage to the wet mechanical separation process. The reason to develop this kind of equipment is the limited availability of water in arid areas or the preference to avoid drying afterwards that requires additions to the wet mechanical processing technologies. Dry gravity separation ensures amongst others an eco-friendly processing, low energy consumption as well as potential cost reduction due to avoidance of process water circuits and of product and tailings dewatering and drying processes.”

The functionality of the AKA-FLOW is based on a combination of an air fluidised bed with a special developed sifter. Studies with different raw materials have shown outstanding performance both in terms of throughput, as well as sorting.“ Due to differences in the behaviour of the materials, it is even more difficult to predict the suitability of the dry sorting process( only on the basis of material data) compared to wet sorting methods. In the meantime, we reached a level with our own AKA- FLOW laboratory unit, that a statement about the general suitability of a material for reprocessing in the AKA-FLOW is possible, so that meaningful results can be achieved even with smaller sample quantities. Recently performed tests show the good results especially for recycling material and two-stage purification.” IM

YOUR

SPECIALIST FOR MINERALS TREATMENT AND ENVIRONMENTAL TECHNOLOGIES

We offer solutions for the wet mechanical and water management processing

AKW EQUIPMENT + PROCESS DESIGN

With more than 50 years of experience in minerals treatment and environmental technologies, hundreds �����������������������������������������������������������������������������������������������������������������

����������������������������������������������������������������������������������������������������������� realize customized processing plants: technically and economically optimized.

OUR CAPABILITIES

Technical Laboratory & Trials

Engineering

Equipment & Process Units

Plant Realization

Spare Parts & Service