Silicates are an indispensable material in many industries. They are used to manufacture fertilizers as well as washing and cleaning products. In the field of water treatment, they help to protect drinking water systems against corrosion. In foundries, they are used as eco-efficient binders. They also serve as a starting material in the production of silica and zeolites.
Liquid silicates have a long and successful history of use, in bulk quantities, in the formulation of cleaning agents and detergents. Many properties of silicates are particularly useful for manufacturers: silicates act as a buffer, as a source of alkalinity and as a detergent builder for neutralizing metals that cause water hardness.
At the same time, they help to reduce surface tension and remove soiling. They disperse dirt, oil and grease particles, thereby preventing these from being redeposited on fibres or surfaces. Silicates also serve as corrosion inhibitors on metallic surfaces.
Sodium silicates have been successfully used for over 90 years as a corrosion inhibitor in drinking water systems. Sodium silicates can be used as the sole agent. No phosphate or other additives are required.
Potassium silicates have a beneficial effect on plant physiology. Apart from being an excellent source of dissolved silicon, they also contain potassium, which acts as a macronutrient for plants.
Potassium silicates serve to strengthen plant cell walls and inhibit pathogen infection. They also enhance photosynthetic efficiency, improve resistance to metallic contaminants and optimize the nutrient balance.
Alkaline silicate solutions, preferably sodium water glass, are the starting materials for silica production by the wet process. Amorphous silica is precipitated through acidification of the silicates.
vanBaerle offers sodium water glass in various formulations for use as the raw material in silica precipitation. Silica is, for example, used in the production of car tyres, toothpaste and scouring cleaners.
Gravity casting with "lost moulds" is a widely used shaping technique in foundries. The moulds are generally made from sand with suitable binders. A model is used to form the contours of the casting as a void within the mould. After pouring, the casting is released by destroying the mould. Bonded sand is also used to produce "lost cores", which are used in the sand- and die-casting processes.
The binders employed for this purpose normally use chemical agents and can be heat-cured (through exposure to heat) or cold-cured (self-hardening through addition of a catalyst or through gas curing). Despite the widespread use of organic binders, inorganic binders based on sodium silicate (water glass) have rapidly gained importance in recent years due to their positive implications for the environment and occupational safety.
Zeolites are used as catalysts in many industrial chemical processes, as separating agents for chemical substances and as water softeners in detergents. The starting materials for synthetic zeolites are sodium silicate (water glass), silica gel or silicic acid (as a source of silicone), and aluminium hydroxide or other aluminium salts (as a source of aluminium). The type of zeolites produced by the reaction mix depends on various factors, e.g. the composition of the reaction mix, stirring rate and crystallization temperature.
Zeolites are crystalline aluminosilicates that occur naturally or can be manufactured synthetically. They have a microporous structure comprising AlO4 and SiO4 tetrahedra, the aluminium and silicon atoms being linked together by oxygen atoms. Depending on zeolite type, this produces a regular pore and/or channel structure in which substances can be absorbed.