I would like to ask some basic questions about the production of fluorosilicic acid by wet phosphoric acid.
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I came into contact with the unfamiliar product fluorosilicic acid during the feasibility study of a new project. I would like to ask you a few questions: 1. Do all domestic wet-process phosphoric acid production units produce by-product H2SiF6 (or Na2SiF6)? Or will some production not recycle fluorine, or form other fluorine products? 2. For every ton of phosphoric acid produced, how many tons of H2SiF6 are generally produced? Is it reasonable to estimate the production capacity of fluosilicic acid based on the total production capacity of wet phosphoric acid? 3. How are wet phosphoric acid and fluorosilicic acid separated in production? What proportion of fluosilicic acid is converted into sodium fluosilicate during production and then sold? 4. What are the main applications of fluorosilicic acid and sodium fluorosilicate on the market currently? To which type of customers are wet phosphoric acid fluosilicic acid mainly sold? 5. In addition to fluosilicic acid, which is a by-product of wet phosphoric acid, what other sources are there for fluosilicic acid production? Thank you all for your generous advice!
Domestic wet-process phosphoric acid production equipment generally has fluorine recovery devices, but there are also some small devices that are not used and discarded. The fluorine recovery in wet-process phosphoric acid is divided into two parts: extraction and phosphoric acid concentration. The fluosilicic acid produced is either sold for takeaway or produced by itself for other downstream products. It mainly produces sodium fluorosilicate or aluminum fluoride. However, with the development of science and technology and market demand, it no longer simply produces sodium fluorosilicate or aluminum fluoride, but produces other products, such as sodium fluoride, ammonium fluoride, anhydrous hydrogen fluoride, etc., as well as the synthesis of some organic fluorides.； The production of fluorosilicic acid cannot be calculated based on the output of phosphoric acid. It also depends on the fluorine content and utilization of the ore used. ； In the production of wet phosphoric acid, fluorosilicic acid is produced by absorbing silicon tetrafluoride produced in the extraction reaction through water, and does not directly generate fluorosilicic acid. After the silica gel is removed by sedimentation, the required fluorosilicic acid is obtained. ； Sodium fluorosilicate is the most widely used fluorosilicate in the construction and building materials industries. Mainly used as enamel cosolvent, glass opalescent agent, acid-resistant cement and acid-resistant concrete coagulant and wood preservative, and used in the pesticide industry to manufacture pesticides. Used as a preservative in the wood industry ； Hygroscopic agent for acid-resistant cement. Used as opalizing agent for glass and enamel ； It is used as a coagulant in natural latex products, as an additive in electrolytic zinc, nickel, and iron ternary plating, and as a plastic filler. In addition, it is also used in the fluoridation treatment of pharmaceuticals and drinking water, and in the manufacture of sodium fluoride for artificial cryolite.
Only the phosphoric acid concentration system of the traditional MAP and DAP devices produces fluorosilicic acid. The slurry MAP does not produce fluorosilicic acid during the concentration process.
Low concentration of fluorosilicic acid can be obtained from the production of calcium chloride
I learned that the production of one ton of wet phosphoric acid can generally produce 0.05~0.06 tons of fluorosilicic acid (100%). I don’t know if this information is accurate. The 4th floor said that low-concentration ammonium fluoride can be obtained from the production of calcium chloride. I don’t know what concentration it refers to?
The answer to the fifth floor question is, it mainly depends on how well you control it. Our calcium chloride production department here produces 8%-12% fluorosilicic acid.
Large-scale wet phosphoric acid production equipment generally has a fluorine recovery device. The recovered fluorosilicic acid includes take-out and production of sodium fluorosilicate, aluminum fluoride, sodium fluoride, ammonium fluoride, anhydrous hydrogen fluoride and the synthesis of some organic fluorides.； The yield of fluosilicic acid is mainly determined by the concentration of concentrated phosphoric acid. If the concentration of phosphoric acid is extremely high, the yield of fluosilicic acid will also be extremely high. Sodium fluorosilicate and aluminum fluoride are mainly used as cosolvents in aluminum smelting.
Nowadays, the fluorine produced during the production reaction of wet phosphoric acid is gradually being utilized. In the past, it was discharged.
This post was last edited by ch4891 on 2010-9-7 11:14 # ecopluto Generally speaking, as long as phosphoric acid is concentrated, fluorosilicic acid will be produced, because a large amount of hydrogen fluoride will overflow during concentration. If it is not recycled, it will cause serious corrosion to the equipment and pollute the environment. During the concentration production, the fluorosilicic acid in the concentrated acid will decompose into silicon tetrafluoride and hydrogen fluoride, enter the fluorine scrubber through the gas phase pipeline, and become fluosilicic acid after being absorbed by water. Generally speaking, the higher the concentration of concentrated acid, the higher the output of fluorosilicic acid, because the fluorine overflow rate is high, and it is also related to the fluorine content in the mine. Generally speaking, a daily output of 670 tons of phosphoric acid can produce 33 tons of 100% fluorosilicic acid. If the concentrated acid concentration is low, the output will be only half or even lower.
Wengfu recycles fluorosilicone into anhydrous hydrogen fluoride and white carbon black