Industrialgrade sodium bicarbonate (NaHCO₃) is widely used in ferrous and nonferrous metallurgy, steel casting, smelting purification and casting sand treatment. Its thermal decomposition property and weakalkaline characteristic help remove impurities, adjust slag performance and improve casting quality. Different mesh sizes are available for different metallurgical working conditions.
1. Steelmaking & Casting Flux Agent
Sodium bicarbonate is added into molten steel as auxiliary flux. Under high temperature, it decomposes and releases CO₂ gas, which produces strong stirring effect inside molten steel.
Promote full separation of slag and molten steel;
Reduce inclusions such as sulfide and oxide inside molten steel;
Improve the fluidity of slag, make impurities float up and be removed;
Reduce pores and sandhole defects of steel ingots and castings, upgrade finished product quality.
It is often used for mediumsmall steel casting, alloy steel smelting, instead of part of soda ash, with less smoke and mild reaction.
2. NonFerrous Metal Smelting (Copper, Lead, Zinc)
In copper, lead and zinc smelting process, sodium bicarbonate acts as pH regulator and slagforming auxiliary agent.
Adjust the alkalinity of smelting slag, optimize slag viscosity;
Suppress volatilization of valuable metal components;
Remove sulfurcontaining impurities in crude metal.
Compared with strong alkali, sodium bicarbonate reacts gently, avoiding excessive local high alkalinity which damages smelting equipment lining.
3. Casting Sand Additive for Foundry
Sodium bicarbonate is mixed into molding sand for steel and iron casting. When pouring hightemperature molten metal, sodium bicarbonate decomposes and releases gas, generating tiny gaps inside sand mold. It greatly improves collapsibility of casting sand. After cooling, the sand is easy to fall off from casting surface, reduces manual cleaning workload, lowers sandsticking and crack defects. This is very popular for precision casting.
4. Metallurgical Wastewater Treatment
Metallurgy plant produces largevolume acidic wastewater containing heavymetal ions (Fe, Cu, Zn, Pb, Cd). Sodium bicarbonate serves as buffer neutralizer: Gently raise pH value without sharp fluctuation; Promote heavymetal ion precipitation and flocculation separation; Avoid overalkalinity problem caused by caustic soda. Meet factory discharge standards for metallurgical wastewater.
5. Pickling Waste Liquid Neutralization & Metal Surface Treatment
During metal pickling process, large amounts of residual acid are produced. Sodium bicarbonate is used for pickling waste liquor neutralization. In addition, finemesh sodium bicarbonate can be used for sodablasting treatment of metal workpieces: remove oxide scale, rust and thermalprocessing carbon deposits without damaging metal base material, pretreatment before electroplating and painting.
6. Safety Reminders for Metallurgical Procurement
Use industrialgrade sodium bicarbonate only; food grade is not costeffective for metallurgy.
Particle size selection: Coarse mesh for casting sand; mediumfine powder for smelting flux.
Storage: Keep sealed and dry, prevent caking.
Supply documents: COA, MSDS available for export.
