Pharmaceutical Industry Sodium bicarbonate can be used directly as a raw material in the pharmaceutical industry to treat excessive stomach acid. Food Processing In food processing, it is the most widely used leavening agent, used in the production of biscuits and bread, and as a carbon dioxide generator in soda beverages. It can be combined with alum to form alkaline baking powder and with soda ash to form household soda ash. It is also used as a butter preservative. Fire Fighting Equipment It is used in the production of acid-base fire extinguishers and foam fire extinguishers. Others In the rubber industry, it can be used in rubber and sponge production; in the metallurgical industry, it can be used as a flux for casting steel ingots; in the machinery industry, it can be used as a molding aid for sand molds in steel casting (foundry); in the printing and dyeing industry, it can be used as a color fixative, acid-base buffer, and post-treatment agent in textile dyeing and finishing. Adding baking soda to dyeing can prevent color fringing on yarn bobbins. In the pharmaceutical industry, it is used as a raw material for antacids. It can also be used as a wool detergent and for soaking seeds in agriculture.