Potash is primarily used as an agricultural fertilizer it’s extracted from beneath the ground by conventional mining or by injecting hot brine which dissolves the potash and salt crystals this solution is then pumped back to the surface where the potash is separated out in settling ponds potash is potassium chloride our compound with the chemical composition KCl it can be processed into a granular agricultural fertilizer or into a higher grade product for industrial use at this Canadian potash mine the ore deposits lie a kilometer underground the ore is comprised of three materials potassium chloride clay and sodium chloride but a known a salt a machine known as a continuous miner is used to cut into the rock face it has two rotors each with three.
Arms each arm has six pairs of bits tipped with ultra strong carbide that bite into the rock and flake off the or the rotor arms sweep the ore into the machine which feeds it though a series of conveyor belts sheets of polymer fastened to the rock above direct the flow of fresh air that’s pumped down into the mine to help ventilator the auras gradually transferred away from the rock face by the network of conveyors at this potash mine ten machines work simultaneously at different locations their conveyors which total 35 kilometres of moving belts converge at the skip a giant elevator bucket which hoists up 45 tonnes of ore at a time to the surface and dumps it into a storage bin another conveyor now transfers the ore to the mill for processing at the mill the all-first tumbles.
Down a series of vibrating screens smaller particles drop through the openings and move on to the next station while larger particles stay on top where a flow of brine washes them into a crusher the finest particles flow to the fine flotation tank while the larger ones sink to the bottom before draining out and travelling to the coarse floatation tank both sets of particles are now treated with chemicals over five minutes the chemical treatment makes the potassium chloride particles attached to air bubbles and right to the surface in the course flotation tank paddles skim the surface pushing the floating potassium chloride into a collector the clay and salt particles are drained from the other end of the tank similarly in the fine flotation unit the potassium chloride.
Particles attach to air bubbles and rise to the top where they overflow into a collector the potash that’s been collected then passes through a centrifuge and a dryer to remove any moisture the dryer feeds a vibrating screening machine which separates the potassium chloride particles into three categories oversized particles are sent back to the crusher under sized particles are sent to machines which can pack them into boards before breaking the boards into new particles which is sent back to the vibrating machine for another round of screening particles of the correct size for the final product are transferred to the shipping warehouse this granular potash will be used as agricultural fertilizer it’s comprised of 95% potassium chloride along with some residual clay and some samples are regularly tested to confirm the potassium chloride content to do this each sample is ground into a fine powder and compressed inside a stainless-steel cap to form a pellet the pellet is then loaded into an x-ray fluorescence analyzer the sample first absorbs energy and then releases it as fluorescent radiation the analyzer.
Measures this fluorescence to determine the samples concentration of potassium chloride the mill also processes potash for industrial use this higher grade potash with the potassium chloride concentration of 99% is a white powder this is made by dissolving the granular 95% potassium chloride in hot brine to remove more of the residual salt and clay the potash is then crystallized by evaporation and cooling to leave potash that’s almost pure potassium chloride it’s fair to say a little more sophisticated than all smock.