In allusion to the problems of long production cycle,high sodium chloride content of products and environmental pollution of reaction waste liquid in carnallite production from salt lake brine,the study of the low-sodium carnallite production was carried out by double brine mixing method based on the theory of the Na⁺,K⁺,Mg²⁺//Cl^-—H₂O quaternary system phase diagram.The highly efficient and fast production of carnallite could be achieved by controlling the ratios of brine mixing and the aging time.The research results showed that in the first brine mixing experiment,when the mass ratio of potassium saturated brine to old brine was 1∶1.8 and the aging time was 4 h,the removal rate of sodium ion was 59.30% and the loss rate of potassium ion was 9.58% in solution.In the second brine mixing experiment,when the mass ratio of potassium-rich brine to old brine was 1∶1.7 and the aging time was 3.5 h,the yields of potassium ion and sodium ion were 62.69% and 8.55% in solution,meanwhile,the contents of carnallite and sodium chloride accounted for 96.96% and 3.04% in the precipitated solid from solution.In addition,the whole experiment process did not need to add the flotation chemicals.This method has the advantages of short production cycle,excellent product quality and environmental friendly,which provides different ideas for the production of carnallite in salt lakes.