Hydrofluoric Acid （HF）
Product Details
Specifications provided
Transparency liquid Content ≥ 35%-55%
(Scope of application reference ‘product usage’)
Hydrogen fluoride gas is soluble in water, and its aqueous solution is called hydrofluoric acid. The product is usually 35%-50% hydrogen fluoride gas aqueous solution, the highest concentration can reach 75%, for the colorless clarified smoke liquid. Smell pungent, volatile, white smoke in the air. It is a medium strength inorganic acid that is highly corrosive and can corrode glass and silicates to form gaseous silicon tetrafluoride. It can also interact with metals, metal oxides and hydroxides to form various salts, but the effect is not as strong as hydrochloric acid. Gold, platinum, lead, paraffin and some plastics cannot use it, so containers can be made. Hydrogen fluoride gas is easily polymerized to form (HF) 2 (HF) 3· homochain molecules, and in the liquid state, the degree of polymerization increases. Store in containers made of lead, wax or plastic. It is highly toxic and can ulcerate upon skin contact.
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Product Parameter
7664-39-3
231-634-8
20.01
Inorganic acid
1.26g/cm³
soluble in water
120(35.3%)
-83.1(pure)
Product Usage
Quartz sand pickling
It works best when treated with hydrofluoric acid, but higher concentrations are required. When shared with sodium disulfite, lower concentrations of hydrofluoric acid can be used. A certain concentration of hydrochloric acid and hydrofluoric acid solution were mixed into quartz mortar at the same time according to proportion; It can also be treated with hydrochloric acid solution first, washed and then treated with hydrofluoric acid, treated at high temperature for 2-3 hours, and then filtered and cleaned, which can effectively remove impurities and oxides on the surface of quartz sand and improve the purity and quality of quartz sand.
Metal surface treatment
Remove surface oxygen-containing impurities, hydrofluoric acid is a weak acid, similar in strength to formic acid. The general concentration of commercially available hydrofluoric acid is 30% to 50%. The main characteristics of hydrofluoric acid rust removal are as follows:
(1) Can dissolve silicon-containing compounds, aluminum, chromium and other metal oxides also have a good solubility, commonly used to etch castings, stainless steel and other workpieces.
(2) For steel workpieces, low concentration hydrofluoric acid can be used for rust removal. Hydrofluoric acid solution with 70% concentration has passivation effect on steel
(3) Hydrofluoric acid with a concentration of about 10% has a weak corrosion effect on magnesium and its alloys, so it is often used in the etching of magnesium workpieces.
(4) Lead is generally not corroded by hydrofluoric acid; Nickel has strong resistance in hydrofluoric acid solutions with concentrations greater than 60%. Hydrofluoric acid is highly toxic and volatile, and is used to prevent human contact with hydrofluoric acid liquid and hydrogen fluoride gas, the etching tank is best sealed and has a good ventilation device, and the treated fluorinated wastewater can be discharged.
Graphite processing
Hydrofluoric acid is a strong acid that can react with almost any impurity in graphite, and graphite has good acid resistance, especially can resist hydrofluoric acid, which determines that graphite can be purified with hydrofluoric acid. The main process of hydrofluoric acid method is to mix graphite with hydrofluoric acid, and react hydrofluoric acid with impurities for a period of time to produce soluble substances or volatiles, after washing to remove impurities, dehydration and drying to obtain purified graphite.
Special for rare earth mining
The preparation method of anhydrous rare earth fluoride is to precipitate hydrated rare earth fluoride from aqueous solution, and then dehydrate or fluorinate the rare earth oxide directly with fluorinating agent. The solubility of rare earth fluoride is very small, and it can be precipitated from hydrofluoric, sulfuric, or nitric acid solutions of rare earth using hydrofluoric acid (the precipitate is precipitated in the form of hydrated fluoride).
TPT-LCD Screen thinning (Electronic grade)
Under the protection of photoresist and edge glue, the concentration of hydrofluoric acid is adjusted, a certain amount of nitric acid, concentrated sulfuric acid and hydrochloric acid are added, and the ultrasonic auxiliary conditions are added, the etching rate is obviously improved. Alternating cleaning can effectively reduce the surface roughness and reduce the precipitation of white surface attachments. The problem of rough surface and white surface adhesion precipitation is solved.
Fiber corrosion
Hydrofluoric acid filled corrosion photonic crystal fiber (PCF). Hydrofluoric acid is filled into the pores of the stretched photonic crystal fiber. By changing its cross section structure, the photonic crystal fiber with specific structure is developed and its optical conductivity is changed. The results show that the leakage loss and scattering loss decrease with the increase of the porosity corrosion degree, the nonlinear coefficient increases obviously, the effective refractive index of the core mold and the equivalent refractive index of the cladding decrease correspondingly, and the group velocity dispersion also changes.
