Orthoboric Acid

• CAS No.: 10043-35-3
• Formula: Bh3o3
• EINECS: 233-139-2
• Appearance: Powder
• Grade Standard: Medicine Grade
• Acid Strength: Strong Acid
• Model NO.: 10043-35-3
• Kind: Organic Acid
• Quality: Tech Grade
• Packaging: Plastic Drum
• Element: Polyatomic Acid
• Oxidation: Oxidizing Acid
• Volatility: Volatile Acid
• Stability: Labile Acid
• Transport Package: in Barrel
• Origin: China
• HS Code: 2810002000

Product Description

Generally, boric acid is not toxic, and the lethal amount of adults is about 15 to 20 grams per kilogram of body weight, while children are 3 to 6 grams per kilogram of body weight. A large dose may lead to acute poisoning, with early symptoms of vomiting, diarrhea, rash, and central nervous system excitation followed by depression. In severe cases, circulatory failure or shock occurs, and death usually occurs within 3 to 5 days. If repeated consumption of small doses will accumulate in the body, resulting in chronic poisoning, anorexia, fatigue, confusion, dermatitis, baldness, menstrual disorders. Boric acid is mainly used in glass products, especially for heat and chemical corrosion resistant glass products. Boron carbide made from boric acid can be used as an abrasive. In addition, it can be used in enamel, ceramic glaze and inorganic pigment, fertilizer and metallurgical production. Boric acid can be prepared by acting sulfuric acid on the hot solution of borax hydrolysis: Na2B4O7+H2SO4+5H2O=Na2SO4+4H3BO3, which can be crystallized when cooled. There are abundant boromagnesite MgB2O5·H2O or 2MgO·B2O5·H2O in northeast China. Boric acid can also be obtained by direct decomposition of boromagnesite with sulfuric acid: Mg2B2O5·H2O+2H2SO4 = 2MgSO4+2H3BO3. Purification of boric acid by activated carbon adsorption method A method of removing impurities from boric acid solution by adsorption of activated carbon. Put the long granular (φ2×10mm) activated carbon (industrial pure) in a porcelain dish, cover it well, and put it into a Muffle furnace (preferably in a tube furnace or vacuum furnace with hydrogen flow) at 800 ~ 900ºC for 1h. Remove and cool, soak in hydrochloric acid (1+1) for a few hours, then boil for half an hour. Filter in Brinell funnel and wash with high purity until chlorine-free. The washed activated carbon is boiled with high purity water for half an hour, dried in the oven at 110ºC, and stored in the dryer for use. Dissolve 70 ~ 80g of boric acid (analytical pure) in 1000ml of high-purity water at a temperature of 70 ~ 80ºC, and then add 10 ~ 20g of treated activated carbon to the solution, stirring at a temperature of 20 ~ 30min without precipitation of boric acid. Then filter it with a Brinell funnel, concentrate the filtrate to 400 ~ 500ml, and cool it to crystallize. The boric acid extracted by filtration is extracted and washed with a small amount of high purity water. Dry the washed boric acid as described above. Boric acid used in disinfection, antisepsis and surgery has weak inhibitory effect on bacteria and fungi. Aqueous solution is acidic, because it is not irritating, it is often used for skin and mucous membrane anticorrosion. Mainly used for mucous membrane and skin damage cleaning agent; It is also used for the cleaning of acute eczema and acute dermatitis with excessive effusion, oral and pharyngitis, fungal disease of the external ear canal, impetigo, skin ulcers and pressure sores. 3% ~ 5% solution is used to wash the wound, 2% solution is used to rinse the eyes and mouth with mucous tissue, 4% solution is used to treat pharyngitis and stomatitis, 2% ~ 3% borate glycerin is used for external otitis, 4% alcohol solution is used for external otitis fungus, 10% ointment is used to treat skin abscess, ulcers and pressure sores. Precautions: Boric acid can be rapidly absorbed from the gastrointestinal tract and damaged skin, and excessive use can cause absorption poisoning, nausea, vomiting, diarrhea, and even circulatory failure. The lethal dose is 10-20g in adults and 3-6g in children. Boric acid solution is strictly forbidden to take orally; The injury of large area is prohibited. TBE buffers are used in molecular biology to dissolve nucleic acids, most commonly in electrophoresis experiments. Boric acid extraction from underground brine The boric acid paste, boron soil, boron feet and other raw materials with a spiral beater into pulp, add hydrochloric acid in the cooking tank after cooking, the pH value of the feed liquid should be maintained at about 2.5, steam heating to 90 ~ 95ºC, cooking 40 ~ 45min, the reaction can be completed. The cooked feed liquid is a supersaturated solution of boric acid at high temperature, the concentration is 11 ~ 12%, and the boric acid content is about 140g/L. The content of insoluble impurities (sediment) in the feed liquid is more, the particles are larger, which can be separated by sedimentation method, the upper clarified liquid is sent to bleaching and decolorization, and the lower sediment (boron mud) contains a large number of mother liquid containing high boric acid, which can be washed with water. The washing operation is divided into 4 times, countercurrent, the first wash water contains more boric acid, is incorporated into the clarifying liquid treatment, the second and third wash water recycling, the last wash water is sent to beating; After 4 times washing, the boric acid content is reduced to less than 2%, which can be used as the raw material of trace boric fertilizer. However, the sedimentation method can only remove most of the insoluble impurities with coarse particles, so it is also necessary to carry out a filtration to remove all the insoluble impurities. The feed liquid is treated with bleach powder before filtration to remove the iron ions and organic impurities generated by the reaction of hydrochloric acid and iron equipment, so that the boric acid product is white in color. The amount of bleaching powder is about 250kg per ton of boric acid products. After bleaching, vacuum filtration is carried out. Because the sediment is very fine, it is easy to plug the filter cloth. Multi-layer filter cloth is often used in operation, and the effect is better. The natural cooling method takes a long time to cool and crystallize the filtered clean liquid, but the crystal particles are large and easy to wash. The product can be obtained quickly by forced cooling method, but the crystal particles are fine and it is difficult to wash. The cooled and crystallized crude boric acid is separated and dehydrated by centrifuge, and washed in centrifuge with industrial water first, and then washed with distilled water until the chloride ion content in the product is qualitatively tested to meet the quality standard. The boric acid products after washing are dried by air flow dryer and then packed in the warehouse. Crude boric acid mother liquor still contains a lot of boric acid, about 40g/L in winter, 60 ~ 80g/L in summer, should Be pumped into the evaporator, evaporation and concentration again, control its pH value of about 2.5, when the mother liquor concentration reaches 10° Be filtration, and then crystallization in the cooling crystallizer, after centrifugal dehydration, washing, drying to get the second batch of products; Then the third operation is performed to obtain the third batch of products. The mother liquid can be boiled with the related feed liquid to produce carnallite. In the whole production process, the boron loss in boron mud and cake accounted for about 5% of the boron content in raw materials. If the management is strengthened to prevent leakage loss, the yield of boric acid can reach more than 80%.