Production process of preparing high-quality potassium chloride from carnallite

A production process of preparing high-quality potassium chloride from carnallite includes the steps of 1) crushing carnallite ore; 2) adding the crushed carnallite ore to a decomposition crystallizer filled with saturated mother liquid; 3) adding fresh water or a washing mother liquid obtained in subsequent processes into the decomposition crystallizer; 4) stirring the slurry so that a quasi-closed loop circulation flowing status that the ore slurry flows from bottom to top in a flow guide cylinder and flows from top to bottom in an annular chamber being adjacent to the external side of the flow guide cylinder is formed, and during the flowing process, the carnallite is decomposed and the potassium chloride is crystallized; and 5) sieving a bottom flow in the decomposition crystallizer, wherein the oversize substance serves as tailings while the undersize substance is filtered then; and 6) feeding a filtrate to the next process to perform evaporation crystallization to recycle the KCl, and washing, filtering