Lignosulfonate in architectural ceramics Applications
Currently in building ceramic body used in the formulation additives are mainly two: one is body enhancer , mainly used to increase the strength of the body , is mainly used in low viscosity carboxymethylcellulose is CMC; a coagulant solution species are primarily used to reduce the viscosity of the mud , reducing the moisture content of the mud to reduce the spray drying tower granulation step water slurry fuel consumption , is used in ceramic manufacturers coagulant solution of sodium silicate and the three main sodium tripolyphosphate.
Analysis of the above additives difficult to find: an organic polymer carboxymethylcellulose , adding the formulation from the body to increase green strength of the effect, but its molecular weight is larger structures chain is longer , in the mud will each kind of fine raw material particles together to form a network structure in the mud wrap free water , the slurry flow variation , adding more worse flowability of mud . To solve the above problems in production only additional water in the mud , the mud weight that reduces the water content increases, the spray granulation step is also increased burnup , the carboxymethyl cellulose added to the formulations in fact contrary to the the purpose of reducing the moisture content of the mud . The STPP is an inorganic coagulant solution , add in the formula can only play a role in reducing discharge slurry flow rate while no effect on the intensity of the green body .
Lignin sulfonate and organic additives are not long molecular chain , it is added to the formulation not only beneficial to reduce the mud flow , and because it has some adhesive properties, can achieve the purpose of increasing green strength . Lignosulfonate can be dissolved in water , Na + ions ionized and lignin sulfonate ion , lignin sulfonate ions and adsorption on the surface of the raw material particles from the reaction of Ca2 + Ca- lignin , dissolved in water Na + instead of Ca2 + adsorbed on the surface of raw material particles , adsorbed on the particle surface portion of bound water is released, the slurry thus increased mobility . Also instead of Na + Ca2 + adsorbed on the surface of the raw material grains ξ- potential of the particles increases , the repulsive force between the particles increases, face to face with the formation of particles , the slurry to increase the number of free water , the slurry will be increased mobility .