The production methods of sodium silicate can be divided into dry and wet processes. Generally, solids are produced using the dry method, then dissolved and converted into the required liquid specifications, with a conversion rate of 1:2.5.

Dry production

The quartz sand and sodium salts (mainly Na2CO3 and Na2SO4) are mixed thoroughly and then melted at a high temperature of approximately 1400°C. Depending on the raw materials, the process is divided into soda ash method and mirabilite method. The production process consists of four stages: batching, calcination, leaching, and concentration.

The specific method for borax is as follows:

1: Blending and Melting: Pure alkali or mirabilite is mixed with quartz sand in proportion using a blender, then it is fed into the storage tank and feed hopper before being added to a reflecting furnace or hoof furnace via a screw conveyor for the melting reaction.

2: Immersion: When the raw material is added to the furnace, molten water glass can flow into the cooling tank through the discharge port and be transported to the storage barrel by a small crawler conveyor. After weighing, the glass blocks in the barrel are lifted using an electric crane and poured into the barrel. An appropriate amount of water is added based on the weight of the bricks and different product specifications, and dissolved with steam. The steam pressure is generally 0.4~0.5MPa, and the liquid barrel rotates at 2~4R/min. After reaching a certain concentration, it is placed in a sedimentation tank for natural sedimentation to remove impurities.

The solution, after removing impurities, is transported to the concentration tank for concentration, where it is indirectly heated by steam. The bottom of the tank is heated by the waste heat from the furnace flue gases. Once the solution has been concentrated to the required concentration, it becomes the finished product.

Wet Process Production

Wet-process production can be divided into traditional wet-process production and atmospheric pressure activated silicon dioxide production. Traditional wet-process production yields high-purity soda ash with low energy consumption, low labor intensity, and readily available raw materials. However, this method can only produce products with a modulus less than 2.5. Its production principle involves dissolving quartz sand in high-temperature caustic soda to form sodium silicate. Atmospheric pressure activated silicon dioxide production is a new method that has emerged in waste treatment in recent years. Few manufacturers use this technique. It can produce products with a modulus ranging from 2.2 to 3.7. The mechanism is to utilize the active silicon dioxide (or silica gel) from by-products or residues in industrial production, heated under atmospheric pressure and reacting with caustic soda to form sodium silicate. The equation is the same as in the traditional wet-process.