Mechanism And The Quantitative Prediction Of Crystalline Sugar And Salt Caking

Most crystalline products are preferred to be produced as single particles with good flowability and stability.These crystal particles are easy to process prior to commercialization.However,caking phenomena of crystals often occur followed by a distinct drying step.It causes dramatically negative effect to the benefit.To solve this problem,this paper focuses on two challenges of crystals caking: mechanism of adhesion process and quantitative prediction of caking ratio and intensity.Firstly,to study the mechanism,method of capillary rise was adopted to measure the contact angles between crystalline particles and relevant liquids.Based on the calculation of adhesion free energy of particles in different liquids with Lifshitz-van der Waals acid-base theory,and the measurement of solubility,the relationship among adhesion free energy,solubility and caking ratio has been established.It is concluded that the adhesion free energy plays a key role in adhesion process,while the formation of crystal bridges depends on the solubility and particles shape.The effects of liquids,particles shape and size were therefore investigated.Secondly,PFC3 D was adopted to simulate particles packing.Combined with the measurements of moisture sorption by DVS and thermodynamics of crystallization,the rate of crystal bridge formation was deduced.On the other hand,the relationship between crystal bridge and caking ratio was studied.Hence,the method of dynamic quantitative prediction of caking ratio and intensity could be accomplished.Finally,based on the thermodynamic research on crystals caking and the quantitative prediction method,the design method of ambient temperature and humidity,solubility,particle shape and size,particle size distribution was discussed to inhibit crystal caking.No similar report to study results above has been reported in literature up to date.