Application of sodium lignosulphonate
Molecular weight: 5000~100000
1. Physical and chemical properties
According to different production materials, sodium lignosulfonate is divided into soft pulp and hard pulp, and softwood lignin is currently widely used. Ligninate, also known as sulfite lignin, has different molecular weights and different structures. It is a heterogeneous anionic polyelectrolyte with polydispersity. The solid product is a brown free-flowing powder, easily soluble in water, easy to absorb moisture, soluble in water of any hardness, and not affected by pH changes, but insoluble in ethanol, acetone and other common organic solvents. It has good chemical stability in aqueous solution, good diffusion performance and heat stability. The aqueous solution is brown to black, with colloidal characteristics, and the viscosity of the solution increases with the increase in concentration. Lignosulfonate has little effect on reducing the interfacial surface tension between liquids, and cannot reduce the surface tension of water or form micelles. Its dispersion effect mainly depends on the adsorption-desorption of the matrix and the generation of charges.
The structural unit of sodium lignosulfonate contains phenolic hydroxyl group and antelope group, which can generate insoluble protein complex, which is used to control suspended solids and iron scale. It has dispersing ability. It is a dispersant and integrator, as well as a retarder. Corrosion agent. In the circulating water treatment agent, the complexation between this product and zinc can be used to store the zinc in the water to continuously provide a certain amount of zinc ions to inhibit the corrosion of the water system. Use it to compound with polyol phosphate and zinc. Dubbed into a compounding agent. Used as a dispersing scale inhibitor in boiler water, its thermal stability is good, and it still maintains good dispersing performance even at 250°C. It is also effective in dispersing water-containing oxides and organic dirt in water. However, its biggest disadvantage is that the composition is unstable, the performance often fluctuates, and it is easy to decompose under high temperature and high pressure, which is very unfavorable for modern water treatment. However, due to its convenient source, low price, and non-polluting advantages, it is still used in a small amount in the compound formulation of the circulating cooling water treatment agent. Generally, the water treatment manufacturer is directly compounded in the water treatment agent product according to the formulation needs.