Do you know what sodium lignosulphonate is?
At present, there are two main additives used in the formulation of architectural ceramics. One is the body strengthening agent, mainly used to increase the strength of the body, is mainly used for low viscosity carboxymethyl cellulose. One is the decoagulant, mainly used to reduce the viscosity of mud, reduce the moisture content of mud to reduce the fuel consumption of dry mud moisture in the granulation process of spray tower. The main deflocculation agents used by existing ceramic manufacturers are sodium silicate and sodium tripolyphosphate.
Carboxymethyl cellulose is a polymer organic matter that, when added to the body formula, plays a role in increasing body strength. However, it has a larger molecular weight and a longer structural chain, which will gather all kinds of fine raw material particles together in the mud and form a network structure to wrap the free water in the mud, making the fluidity of the mud worse. The more you add, the less fluid the mud.
In order to solve these problems in production, additional water was added to the mud. In this way, the proportion of mud decreases, the water content increases, and the fuel consumption of the spray granulation process also increases, so the addition of carboxymethyl cellulose in the formula actually violates the purpose of reducing mud moisture content. However, sodium tripolyphosphate is an inorganic decoagulant, which can only reduce the flow rate of the slurry and has no effect on the strength of the body.
Sodium lignosulphonate is an organic additive and the molecular chain is not long. It is not only conducive to the reduction of mud flow rate, but also because of its certain bonding performance, can achieve the purpose of increasing the strength of the body. Sodium lignosulphonate can dissolve in water, ionizing sodium ions and lignosulfonate ions. Lignosulphonate ions will react with calcium ions adsorbed on the surface of raw material particles to generate calcium ions lignin, so that sodium ions dissolved in water instead of calcium ions adsorbed on the surface of raw material particles. Some of the bound water adsorbed to the surface of the particles is released, thus increasing the fluidity of the mud.
In addition, sodium ions instead of calcium ions adsorbed on the surface of raw material particles to increase the negative potential of raw material particles. As a result, the repulsive force between the particles increases, face junctions form between the particles, the amount of free water in the mud increases, and the fluidity of the mud improves accordingly.
The introduction of sodium lignosulphonate into the building ceramic body formulation not only reduces the cost of the body formulation, but also significantly reduces the water content of mud due to its certain decoagulation effect, saving the fuel consumption of spray towers. Combined with its good adhesion, it improves the dry strength of the body, reduces the cracked bricks in production, and thus increases the yield of semi-finished products. Therefore, sodium lignosulphonate is a rare ceramic additive.
However, it is worth noting that the effect of sodium lignosulphonate from different manufacturers on mud decoagulation and strengthening of the body is different. This may have a great relationship with the structure and composition of sodium lignosulphonate produced by different manufacturers. Thus, comparing different sodium lignosulphonate, considering the price and the effect of use to choose which manufacturer of sodium lignosulphonate before buying.