Boric acid is mainly used in the deashing link in the leather industry, and deashing: is a term in the leather industry. Remove the alkaline material from the limed bare hide, eliminate the swelling of the bare hide, and facilitate the operation of the subsequent process. The purpose of deliming is to reduce swelling and lower pH.
Deliming materials include strong acid and weak base salts (such as ammonium sulfate, ammonium chloride, etc.), non-expanding acids (such as lactic acid), and some manufacturers use ammonium sulfate (market price: 500-600) for deliming due to cost considerations. Ammonium sulfate will produce a large amount of ammonia gas when it encounters lime. If the exhaust air of the drum is blocked, the ammonia gas will be difficult to disperse. It will seriously cause drum explosion and ammonia poisoning accidents for workers! It will also cause the ammonia nitrogen value of the sewage to exceed the standard. The ammonia nitrogen value exceeding the standard will cause the death of microorganisms in the sewage pool due to hypoxia, which directly affects the sewage treatment effect! However, boric acid is weakly acidic and is used to adjust the pH, neutralize the alkalinity of the lime to neutralize the swelling state of the bare skin, and provide appropriate operating conditions for the subsequent process.