Silica gel desiccant is the most widely used moisture drying agent in the martest . Its chemical formula is Sio2.nH2o, very stable. Silica gel desiccant can be directed contacted with foods and drugs because it is non-toxic ,food grade, and environmental.
How does the silica gel desiccant be created ? To produce desiccant ,we need to prepare some sodium metasilicate, water glass, sulfuric acid.
First , blend alkali and acid , then melted and filtered solid sodium silicate in high temperature to a certain concentration of liquid, then formulate the sulfuric acid to a 20% concentration liquid.
Second, Gel granulation. Mix the sodium silicate solution and sulfuric acid solution together to gel granules. We can dicide the size and shape of the particles according demand and supply ability .
Third , Ageing . To age the gel granules , it must need a certain period of time ,temperature and PH value to make the skeletons firm . During the process, the glue condensation become to Si-o-Si bond ,so as to enhance skeleton, narrow space and squeeze out the water.
Fourth, pickling ,washing and gel washing . Because , there are some Na2SO4 on the gel particles , we must pickle, wash and wash gel , control the anions and cations so as to meet the craft requirements. these process largely makes the prameters of silica gel desiccant.
Fifth, Drying . After washing ,we need to put the water gel particles into drying room .Drying the beads to the requirement range, the higher the temperature is ,the faster the particle aggresgation and the large of the pore size are.
Sixth, Slection. Using ball screening machine, clarify the dry silica gel particles according different sizes and diameters, thus we can distinguish good silica gel desiccants and bad ones.
Seventh, plastic pick. pick the silica gel with colors except transparent and the impurities out, then, seal the beads with composite paper.
Finally, the silica gel desiccant is created.
