Caustic Dissolution |
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Caustic dissolution utilizes total liberation
techniques to give an accurate diamond distribution
in the rock. Mechanical milling is avoided whenever
possible. A proprietary rock breaker is used only if
the sample is too large to be dissolved. Samples
received are photographed and dried for moisture
content analysis prior to processing. Samples can
range from grams to hundreds of kilograms. Our 6
kilns are capable of processing up to 50 kilograms a
day. Samples are loaded into large steel pots and caustic soda is added to dissolve the rock. The dissolution takes place over many hours in temperature controlled kilns. Once the reaction is complete the residue is cooled and dissolved in water. The slurry is then cooled and poured through stainless steel screen to avoid screen distortion and loss of fine diamonds. Once the sample is recovered from the screen and neutralized a determination is made whether further dissolution is required in order to achieve total liberation of the diamonds. All samples undergo a micro fusion to clean the sample prior to observation. In the case where abundant oxides remain in the residue additional dissolutions can be performed using a variety of chemicals to reduce the size of the concentrate prior to observation without harming the diamonds. Quality control grains are added to each and every aliquot that undergoes the caustic dissolution process. 10 high quality synthetic diamonds ranging from 0.18mm to 1.0mm are added to every pot and recovered at the observation stage. |
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