The reconcentration XRT sorting machine is already commercially available and the SPS version will be available before year-end
De Beers Technologies SA (DebTech), part of global diamond miner De Beers, constantly introduces new products into the diamond and mineral processing market. The most recent innovations include a range of diamond sorting machines based on X-ray transmission (XRT) technology, as well as an innovative instrument for determining the density profile of an ore sample.
A suite of three XRT-based systems will cover the –75 mm to +1 mm size range typically processed in diamond plants and can be used for middles and coarse dense-media separation (DMS) replacement, reconcentration and final diamond sorting, as well as traditional primary recovery plant sorting applications.
One of the big advantages of the XRT technology is that its detection capability covers all diamonds, irrespective of type, quality, colour or temperature. Type IIA, brown or yellow diamonds are all detected with the same ease.
The XRT coarse concentrator was designed with high throughput diamond sorting in mind and was specifically targeted at middles and coarse DMS replacement. This unit successfully passed a field trial in this application on the Namibian West coast and is now commercially available. The design of this machine is such that the yield is sufficiently low that no additional reconcentration is required and the product can be dispatched directly to a sort-house facility. The unit is capable of processing diamond ore at a throughput of up to 200 t/h.
The system is housed in a standard shipping container and is designed to be completely self-contained. The required compressed air, chilled water and uninterruptable power supply are internally supplied. In addition, the system is equipped with a feed control algorithm, which removes the need for additional weigh feeders.
An important feature is the ability to provide on-line feedback of the size and frequency of detected diamonds and the size distribution of the treated ore.
The second XRT sorting unit addresses the reconcentration and single particle sorting application space in the size range –32 mm to +1 mm. The reconcentration machine is currently available commercially and the SPS version will be available before the end of 2016. The SPS version has a design goal of producing a concentrate in the order of 99% diamond by weight.
The final application in this new suite of sorting units addresses the traditional recovery plant application and will cater for –32 mm to +1 mm material. The design of this unit is expected to be completed in early 2017. It will have both wet and dry treatment capability and will exceed the diamond discrimination, throughput and recovery efficiencies of the currently available X-ray luminescence-based sorting machines.
A new development by DebTech is an instrument designed to measure the density distribution of ore particles. The instrument known as RhoVol, is a direct measurement of density on an individual particle basis and produces a highly repeatable density distribution in a fraction of the time required using traditional heavy liquid sink-float methods. In comparative testing, the RhoVol required two working hours, compared with the 45 working hours required by the sink-float method.
The system is independent of ore type and has no practical limitation on the density range that it can measure. Three embodiments of the RhoVol unit are planned to cater for fines from –3 mm to +1 mm, middles from –8 mm to +3 mm and coarse material from –32 mm to +8 mm particle size distributions. The –8 mm to +3 mm unit is currently commercially available, with the coarse and fines units both to follow in 2017.
Further enhancements include a sorting facility where particles can be sorted into density bins for further analysis. Information such as the number of particles processed, compactness, elongation, square mesh, calliper size, minimum enclosed sphere and many more are available from the system.
DebTech offers comprehensive product support from research and development to manufacturing, sales, commissioning and after-sales service.
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