Ceramic Membrane for Silica Sol Concentration

Silica sol is a colloidal solution formed by uniformly dispersing nano-scale silicon dioxide (SiO2) particles in water or an organic solvent. It has the characteristics of high dispersibility, high specific surface area, good adhesion, and safety and non-toxicity. Silica sol is widely used in many fields due to its unique properties , such as precision casting, papermaking, coatings, textiles, polishing, refractory materials, food, chemical catalysts, and the electronics industry.

There are many methods for preparing silica sol, including ion exchange, sulfuric acid neutralization, hydrolysis of silicate, etc. Among them, ion exchange is one of the most common methods, which uses ion exchange resin to remove sodium ions in sodium silicate solution to obtain a stable silica sol dilute solution. However, in the concentration stage of silica sol production, traditional concentration methods generally use reduced pressure dehydration or polymeric tubular or hollow fiber ultrafiltration membrane process. They have the following disadvantages:

Disadvantages of dehydration by Reduced Normal Pressure process:

>>High energy consumption

>>Long cycle

Disadvantages of polymeric ultrafiltration membranes:

>>Not resistant to high temperature

>>Not resistant to acid and alkali

>>Cannot regenerate acid and alkali multiple times

>>Short membrane life

>>Unstable product quality

Ceramic membrane is an asymmetric membrane made of inorganic ceramic materials through a special process. It usually has a three-layer structure, including a porous support layer, a transition layer and a separation layer, which are asymmetrically distributed. The support layer provides mechanical strength, the transition layer prevents particle penetration during the membrane preparation process, and the separation layer has selective permeability.

CRM ceramic membrane separation process is a fluid separation process in the form of "cross-flow filtration". Under pressure, the raw liquid flows inside the membrane tube or outside the membrane, small molecules (or liquids) pass through the membrane, and large molecules (or solids) are retained by the membrane, thereby achieving the purpose of separation, concentration, purification, etc.

Ceramic membranes are used in silica sol concentration due to their material and structural characteristics.

TANGENT Crossflow ceramic membrane has been widely applied for silica sol industry:

High filtering accuracy, the filtering pore size can reach a minimum of 5 nanometers ;

>>Can work continuously with high reliability;

>>Thermal stability, operating temperature can reach 150 ℃ ;

>>Resistant to strong acids, alkalis, corrosion, oxidation and organic solvents;

>>High throughput, backwash capability, high efficiency;

>>Only water and salt are allowed to pass through,Silica sol can be effectively concentrated;

>>Can remove small amounts of ions and soluble substances ;

>>Long membrane service life ;

>>Easy to operate and low maintenance cost;

At present, ceramic membranes have been widely used in the silica sol concentration process. They can not only improve the production efficiency and product quality of concentrated silica sol, but also reduce production costs and energy consumption, which have been proved to be an indispensable process in silica sol production.