Preparation Of Spherical Potassium Chloride And Its Agglomeration Process And Mechanism

Industrial grade KCl is mainly used in agricultural production in the form of potash fertilizer,which is of great significance for ensuring safe food production.However,due to the small particle size and cubic characteristics of its products,the particles have the phenomenon of serious caking,which has become the main bottleneck restricting the development of the potash industry.Spherical particles have obvious advantages in product anti-caking properties and fluidity due to their morphology and particle size characteristics,and provide an effective solution strategy for improving the anti-caking problems of KCl particle products.In this paper,the cooling crystallization method was used to reveal the process and mechanism of spherical KCl agglomeration through theoretical model calculations and the addition of metal cations,so as to realize the stable preparation of spherical potassium chloride.To improve the quality of spherical products and broaden the application of spherical crystallization technology in inorganic salt crystallization,the crystallization parameter screening,process optimization and practical application were executed.It mainly involves the following:1.The theoretical model was used to calculate the influence of each crystallization parameter on the coalescence behavior of spherical potassium chloride.Based on the classical wetting theory,Lifshitz-Van der Waals acid-base theory and fluid force theory,the crystallization conditions were calculated from the perspective of the adhesion and dispersion force of the crystalline particles by measured the basic crystallization parameters of KCl.2.Achieved the stable preparation of spherical potassium chloride and explained its agglomeration and crystallization process and mechanism.By discussing the phenomenon that the presence of a small amount of Al³⁺in the crystallization system can effectively promote the preparation of spherical KCl,the agglomeration process and mechanism of spherical KCl were explained,and other metal ions were used to verify the mechanism.The experimental results show that the influence mechanism of Al³⁺on the preparation of spherical KCl is universal,which explains the agglomeration and crystallization process and mechanism of spherical KCl.3.The effect of basic crystallization conditions on the preparation of spherical KCl was investigated.The influence of basic conditions such as different stirring rate,cooling rate,and initial crystallization temperature on the preparation of spherical KCl were investigated.In the sample evaluation method,a statistical comprehensive evaluation strategy with average sphericity,average particle size and dispersion as indicators were introduced to evaluate the comprehensive quality of the prepared samples,so as to screen the best process conditions for preparing spherical KCl.4.Further improve the sphericity of the sample through the 2-step crystallization method.The spherical KCl was prepared by aging the primary particles.It mainly examined the influence of the size of primary particles,the number of primary particles and the morphology of primary particles on the maturation into balls,so as to analyze the similarities and differences of the maturation process of different primary particles,and evaluate the pros and cons of the method in improving the sphericity of the sample.5.Preparation of spherical KCl using low-sodium carnallite as raw material.Based on the preparation technology of spherical KCl using pure KCl as the raw material,by adjusting the experimental parameters,an attempt was made to prepare spherical KCl in a more complex low-sodium carnallite system.Through this way,we will explore whether the preparation technology of spherical KCl with analytical purity as the raw material has the potential for universal application in a more complex system.