Study On Theory And Technology Of Flotation Of Potassium Salts In Sulfate-type Lake Of Lop Nur

Xinjiang Lop Nur Salt Lake is the largest potassium sulphate brine deposit in China.Through the exploitation and utilization of Lop Nur salt lake,SDIC Xinjiang Lop Nur Potash Co.Ld(SLNP)become the world's largest single potassium sulphate production base.Due to the complicated system of the sulfate-type brine,the carnallite from evaporating brine is usually accompanied by serval impurity salts,which lead to the low flotation efficiency and high Na Cl content in concentrate.It is more severe during summer season,which is a major technical challenge.Solving this problem has important theoretical significance and significant economic value to the high-efficiency development and utilization of the Lop Nur Salt Lake resources and the development and utilization of other sulfate-type potash deposits in the world.The interface properties between KCl and water and the mechanism of KCl and collector were studied by pure mineral flotation and molecular dynamics simulation,and further clarified the flotation mechanism and behavior of KCl.Then based on the special system of sulfate-type brine,the effects and mechanism of Mg²⁺,SO₄^2-impurity ions and fine kainite particles on the KCl flotation were studied.On the basis of theoretical research,a new model of starvation feeding the collector-multi rate flotation was proposed,and laboratory and industrial tests were carried out.The main contents and results are listed as follows:(1)A new mechanism of flotation of KCl was proposed according to the hydration layers.It was found that the amine collector could penetrate the hydration layer of KCl surface and failed to penetrate the hydration layer of Na Cl surface,thus,the flotation separation of KCl and Na Cl was achieved.(2)The adsorption of amine collector on KCl surface was well fitted by Langmuir model,which was mainly electrostatic physical adsorption.(3)The ions were present on the hydration layer of Na Cl and KCl surface in the form of ionic hydration shell.The stronger ionic hydration was,the greater the enhancement of the cohesive energy between the water molecules in the surface hydration layer of KCl and Na Cl,and the difficulty of the amine collector penetrating the hydration layer increased.It was revealed that the hydration of Mg²⁺increased the cohesive energy of water molecules on the KCl surface and the amine collector was more difficult to be adsorbed by KCl.(4)The flotation kinetics of KCl and Na Cl are quite different,and this difference is more significant when the amount of collector is low.Increasing the amount of collector could improve the separation velocity of KCl and Na Cl,whereas the recovery remained.(5)Based on the flotation kinetics of KCl and Na Cl and the mineral characteristics of fine kainite particles,a new process of starvation feeding the collector-multi rate flotation was proposed,in which with low concentration of amine collector,the high-quality KCl(with low Na Cl content)could be obtained.(6)The process of starvation feeding the collector-multi rate flotation was confirmed by industrial tests.The content of Na Cl in KCl concentrate reduced 16.53%and the dosage of collector reduced 36.55%.The process not only lowered the re-washing intensity of KCl concentrate,reduced the dissolution loss of potassium,but also realized the dramatic decrease in consumption of ore,reagents and electricity,which reduced the production cost significantly.