Laboratory Testing & General Mineral Processing Engineering

Laboratory Testing & General Mineral Processing Engineering

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Diamond Fluorescence Sorting XRT (3 replies)

Zander Barcalow
8 years ago
Zander Barcalow 8 years ago

Can somebody please help with information about UV and visible light diamond sorting.

(unknown)
8 years ago
(unknown) 8 years ago
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Steinert are one of the German equipment manufacturers that could provide good feedback. Traditional diamond sorting has been done using x-ray sorters which rely on the luminescence of the diamonds to select the stones. However not all diamond can be identified this way with 1% losses overall (quoted number) but with variations between operations. Some deposits will have a much higher loss ratio.

I know of one company that worked with a Canadian diamond mine to improve recovery using visible light sorters with optimized background on the x-ray

(XRT Fluorescence

)

sorter reject stream. The use of UV/visible light automated sorting is likely to improve recovery for most diamond operations. As far as choosing the ''best'' option that will be down to experience (therefore equipment manufacturers/end users input) and testing of the particular feed material (given the inherent variation that exists).

(unknown)
8 years ago
(unknown) 8 years ago
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Contact Alfred at Optosort - they have supplied sorters to De Beers and other diamond mines. a.freh(at)optosort.com. Their newest machines are aimed at the broader ore separation processes including minerals such as limestone, calcite, magnesite, dolomite, feldspar, silica/quartz, base metals such as iron, copper, nickel, manganese, tungsten, zinc, etc as well as precious metals such as gold and PGM's. They also remove shale from coal.

R
richardh
8 years ago
richardh 8 years ago
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1 like by David

I was fortunate to spend a large amount of time in many of The DeBeers operations in the final recovery sections. Something which I enjoyed.

Amongst the "visual" means of recovering diamonds there are a few ways.

Optical sorting, which is basically the way it looks. This can struggle in some of the plants with a mix of boart and gem quality stones. The material has to be clean and properly presented.

Luminescent (flourescence)sorters. Traditionally X-ray based (XRL), where the particles are subjected to X-ray and then "glow". Most of the traditional automated X-ray sorters used this. DeBeers DebTech division and others have designed UV machines as well, which pick up on response to UV. the problem is some Type II diamonds exhibit low or neglible luminescent.

XRT (X-ray transmission)is transmission. simplistically much like a doctors X-ray, but akin to a security baggage X-ray, where dual X-ray (or simulated) are transmitted through the particles and then analysed through a detector array on the other side. It essentially sorts on atomic density, once the X-ray sources and optic software is tuned for the diamond. This to me is most exciting technology as it not dependant on the material being surface clean and not as carefully pre sized as the others. It also lends itself to high throughputs.

I hope this helps.

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