The present disclosure provides a potassium aluminum fluoride (KAlF.sub.4) flux agent having improved properties such as a lower melting point which allows for the use of solders and alloys with lower melting points. The potassium aluminum fluoride (KAlF.sub.4) flux agent may also allow for faster brazing of standard alloys.

The invention provides a potassium cryolite for aluminum electrolysis industry, which has a molecular formula: mKF.AlF.sub.3, wherein m is from 1 to 1.5. The low-molecular-ratio potassium cryolite (mKF.AlF.sub.3, and m is from 1 to 1.5) provided by the invention is used for aluminum electrolysis industry, and can improve the dissolvability of aluminum oxide, thus reducing the temperature of electrolysis and the consumption of power, raising the efficiency of electrolysis and lowering the comprehensive production cost.

The invention provides a potassium cryolite for aluminum electrolysis industry, which has a molecular formula: mKF.AlF.sub.3, wherein m is from 1 to 1.5. The low-molecular-ratio potassium cryolite (mKF.AlF.sub.3, and m is from 1 to 1.5) provided by the invention is used for aluminum electrolysis industry, and can improve the dissolvability of aluminum oxide, thus reducing the temperature of electrolysis and the consumption of power, raising the efficiency of electrolysis and lowering the comprehensive production cost.

The present disclosure provides a free flowing potassium aluminum fluoride (KAlF.sub.4) flux agent (e.g., for plasma flux applications), having improved properties such as a more spherical morphology that is resistant to caking. The potassium aluminum fluoride (KAlF.sub.4) flux agent is rendered free flowing due to the starting temperature and rate of addition of potassium hydroxide when producing KAlF.sub.4.

The present disclosure provides a free flowing potassium aluminum fluoride (KAlF.sub.4) flux agent (e.g., for plasma flux applications), having improved properties such as a more spherical morphology that is resistant to caking. The potassium aluminum fluoride (KAlF.sub.4) flux agent is rendered free flowing due to the starting temperature and rate of addition of potassium hydroxide when producing KAlF.sub.4.

The present invention relates to processes for producing fluorine-containing compounds by means of precipitation reactions from solutions containing fluoride ions wherein the pH value is determined using an electrochemical measuring chain and to electrochemical measuring chains for determining pH values.

The present invention relates to processes for producing fluorine-containing compounds by means of precipitation reactions from solutions containing fluoride ions wherein the pH value is determined using an electrochemical measuring chain and to electrochemical measuring chains for determining pH values.

Non-hygroscopic brazing fluxes, methods for producing non-hygroscopic brazing fluxes, and methods for producing hydrated cesium aluminum fluorides are provided. An exemplary method for producing a non-hygroscopic brazing flux includes preparing a mixture including aluminum, cesium, and fluorine. The prepared mixture has an aluminum:cesium:fluorine molar ratio of about (1):(1.1-1.2):(4.0-4.2). The method further includes drying the mixture at a temperature higher than about 90 C. to form a product comprising at least about 20 mass percent hydrated cesium aluminum fluoride, based on the total mass of the product.

Non-hygroscopic brazing fluxes, methods for producing non-hygroscopic brazing fluxes, and methods for producing hydrated cesium aluminum fluorides are provided. An exemplary method for producing a non-hygroscopic brazing flux includes preparing a mixture including aluminum, cesium, and fluorine. The prepared mixture has an aluminum:cesium:fluorine molar ratio of about (1):(1.1-1.2):(4.0-4.2). The method further includes drying the mixture at a temperature higher than about 90 C. to form a product comprising at least about 20 mass percent hydrated cesium aluminum fluoride, based on the total mass of the product.

Provided are a liquid dispersion of fluoride particles having a refractive index lower than that of, for example, magnesium fluoride, the liquid dispersion being excellent in dispersibility and suitable for production of an optical film such as an antireflection film; a composition for forming an optical film; and an optical film. A liquid dispersion of fluoride particles according to the present invention contains: fluoride particles; an anionic surfactant as a dispersant for the fluoride particles; and an organic solvent, wherein the fluoride particles contain at least aluminum, an alkali metal, and an alkaline earth metal as an optional element in a composition of the fluoride particles, and the fluoride particles are dispersed in the organic solvent.