The selection of acid-resistant pumps has always been one of the most troublesome questions for chemical practitioners. Slight carelessness can damage equipment and cause accidents or even lead to catastrophe. According to the statistics, about 60% of the destruction of chemical equipment is caused by corrosion. Therefore, the selection of chemical pumps should first pay attention to the scientific material selection. There is often a misunderstanding that stainless steel is a "universal material," no matter what the media and environmental conditions are held out of stainless steel, which is very dangerous. The following for some common chemical media to talk about the selection of the main points: 1. Sulfuric acid as a strong corrosive medium, sulfuric acid is a very broad use of important industrial raw materials. Different concentrations and temperatures of sulfuric acid on the corrosion of materials vary greatly, for the concentration of more than 80%, the temperature is less than 80 â„ƒ of concentrated sulfuric acid, carbon steel and cast iron has good corrosion resistance, but it is not suitable for high-speed flow of sulfuric acid, Not suitable for pump valve material; common stainless steel such as 304 (0Cr18Ni9), 316 (0Cr18Ni12Mo2Ti) sulfuric acid medium is also limited use. Therefore, the delivery of sulfuric acid pump valve is usually made of high silicon cast iron (casting and processing difficult), high alloy stainless steel (No. 20 alloy) manufacturing, but its processing is difficult and expensive, so people are not optimistic. Fluoroplastics alloy has very good resistance to sulfuric acid. It is the patented material of Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences. Our company introduced the patented technology in 1985 and the earliest use it to develop and produce corrosion-resistant chemical pump. After the experiment of the Chinese Academy of Sciences, There is no chemical medium to react with it, so using a fluorine-based pump (F46) is a more economical option. Green ring pump company applicable products: IHF lining pump, FSB strong corrosion-resistant centrifugal pumps, IMD fluorine plastic magnetic pumps. 2. Hydrochloric acid solution Most of the metal materials are not resistant to hydrochloric acid corrosion (including a variety of stainless steel), molybdenum high ferrosilicon can only be used for 50 â„ƒ, 30% hydrochloric acid. In contrast to metallic materials, the vast majority of non-metallic materials have good corrosion resistance to hydrochloric acid, so lined rubber pumps and plastic pumps (such as engineering plastics, fluoroplastics, etc.) are the best choice for the delivery of hydrochloric acid. Green Central pump for the company's products include: CQB fluorine plastic leak-free acid pump, CQF plastic magnetic pump (or fluorine plastic magnetic pump). 3. Nitric acid Most metals are mostly corrosive in nitric acid corrosion damage, stainless steel is the most widely used nitric acid-resistant materials, all concentrations of nitric acid at room temperature have good corrosion resistance, it is worth mentioning that the molybdenum-containing stainless steel (such as 316,316 L) corrosion resistance to nitric acid is not only not superior to ordinary stainless steel (such as 304,321), and sometimes even worse. For high temperature nitric acid, usually using fluorine plastic alloy material. Company products are: CQB fluorine plastic alloy magnetic pump, FSB fluorine alloy centrifugal pumps. 4. Acetic acid It is one of the most corrosive substances in organic acids. Ordinary steel will be seriously corroded in all concentrations and temperatures of acetic acid. Stainless steel is an excellent acetic acid-resistant material. Molybdenum-containing 316 stainless steel is also suitable for high temperature and Dilute acetic acid steam. For high temperature and high concentration of acetic acid or other corrosive media containing harsh requirements, the choice of high-alloy stainless steel or fluorine plastic pump. Such as the Central Central pump company produces CQB magnetic pump, CQ stainless steel magnetic pump. 5. Alkali (sodium hydroxide) is generally not very corrosive, but the general alkaline solution will produce crystals, so the choice of material with a mechanical seal graphite 169 graphite type FSB fluoride alloy alkali pump 6. Ammonia (ammonia hydroxide) Most Corrosion of metals and non-metals in liquid ammonia and aqueous ammonia (ammonia hydroxide) is minimal and only copper and copper alloys should not be used. Most of the company's products for ammonia and ammonia transport. Such as the ring pump company produces CQF engineering plastic magnetic pump, FSB fluorine alloy centrifugal pump is better 7. Saline (sea water) Ordinary steel in sodium chloride solution and seawater, salt water corrosion rate is not too high, the general shall be used paint protection; Various types of stainless steel also have a low uniform corrosion rate, but may cause localized corrosion due to chloride ions, usually 316 stainless steel is better. Green Central pump all types of chemical pumps have 316 material configuration, such as IH chemical centrifugal pumps. 8. alcohols, ketones, esters, ethers Common alcohol mediums are methanol, ethanol, ethylene glycol, propanol, ketones have acetone, butanone and so on, the ester medium has a variety of methyl esters, Ethyl ether, ethers medium ether, ether, butyl ether, their basic corrosive is not strong, so you can use ordinary stainless steel, the specific selection should also be based on the media properties and related requirements to make a reasonable choice. It is also noteworthy that ketones, esters, ethers are soluble in a wide variety of rubbers and avoid mistakes when selecting sealing materials. It is recommended to choose inorganic seal fluorine plastic magnetic pump.