What is Trisodium hexafluoroaluminate?

This is cryolite. Cryolite, its chemical name is trisodium hexafluoroaluminate, and the chemical formula is $Na_3AlF_6 $.

If the cryolite is glass, it is often white, colorless, or light gray, light brown, light green, light red and other colors. It is brittle and shiny. It is mostly found in granite pegmatites and related deposits of alkaline syenite.

Cryolite is widely used in industry. In the aluminum smelting industry, it is a key flux, which can greatly reduce the melting point of alumina, greatly reduce the energy consumption of the electrolysis process of aluminum, and greatly increase the efficiency. It greatly promotes the large-scale production of aluminum. In the foundry industry, it can be used as a flux to help the flow of molten metal and make castings better formed. In the glass and ceramic industries, it can also play an important role in adjusting the melting temperature of glass and improving the properties of ceramic glazes.

In the past, cryolite was highly valued by craftsmen and Fang families because of its special properties and uses. Although the understanding of its chemical composition at that time may not be as accurate as it is today, the ancestors have explored many wonderful uses of cryolite in practice, making extraordinary contributions to metallurgy, process production and other fields, and its achievements are indelible. Today, cryolite still occupies an indispensable position in the modern industrial system and continues to contribute to industrial development.

What are the main uses of Trisodium hexafluoroaluminate?

The main uses of trisodium hexafluoroaluminate, that is, cryolite, are as follows:

In the aluminum smelting industry, it is very important. When bauxite smelts aluminum, cryolite is used as a flux. The melting point of aluminum is quite high, about 660 ° C, and the energy consumption of melting alone is huge. Cryolite can reduce the melting point of aluminum oxide, so that it can be melted at about 950-1000 ° C. In this way, the energy consumption of aluminum smelting is greatly reduced, and the production cost is reduced. Without cryolite, the cost of aluminum smelting may be several times that of today, and it is difficult for aluminum products to be used so widely.

In the field of casting, it is also useful. As a modifier for casting aluminum alloys, it can refine the alloy grains. After its treatment, the strength, hardness and toughness Taking the casting of automobile engine block as an example, the addition of cryolite modification treatment can improve the performance and quality of the cylinder block and make it more durable.

In the enamel industry, cryolite is also indispensable. As one of the raw materials for enamel glaze, it can reduce the melting point of the glaze, increase its fluidity and gloss. In this way, the surface of enamel products is smoother and brighter, the color is uniform, and the wear resistance and chemical corrosion resistance are also good. The enamel kitchenware and sanitary ware made are not only beautiful, but also have a long service life.

In glass manufacturing, cryolite is used as a flux and an opacifier. As a flux, it can reduce the melting temperature of glass raw materials, save energy, and improve production efficiency. As an opacifier, it can make glass opaque and is used to make opalescent glass, decorative glass, etc., to enrich the variety of glass products.

What are the physical and chemical properties of Trisodium hexafluoroaluminate?

The physicochemical properties of trisodium hexafluoroaluminate, that is, cryolite, are as follows:

This substance is white in color and often in a crystalline or powdery state. Its melting point is quite high, about 1,000 degrees (1009 ° C), and its boiling point is also high, up to 2,000 degrees (2275 ° C). The density is about 2.9 grams per cubic centimeter (2.95g/cm ³).

Cryolite is slightly soluble in water and slightly more soluble in hot water. Its chemical properties are stable, and it is not easy to react with other substances at room temperature. When exposed to strong acids, it decomposes and releases hydrogen fluoride gas.

In industrial applications, cryolite is particularly a heavy agent for aluminum smelting. Because it can reduce the melting point of alumina and reduce the energy consumption of aluminum smelting. And because of its stable chemical properties, it can ensure the stability of the aluminum smelting process. In addition, it is also used in the glass and ceramic industries, and can be used as a flux, which has a good melting effect, making the production process smoother and the product quality better.

What are the production methods of Trisodium hexafluoroaluminate?

There are roughly several ways to make trisodium hexafluoroaluminate (cryolite).

One method is to co-heat fluorite (CaF ³) with sulfuric acid to obtain hydrogen fluoride (HF) gas. The reaction is as follows: CaF ³ + H2O SO (concentrated) → CaSO+ 2HF ↑. After that, the hydrogen fluoride gas is introduced into the mixture of aluminum hydroxide (Al (OH) 🥰) and sodium carbonate (NaO2 CO 🥰). After a series of reactions, cryolite can be obtained.

The second method is to use natural cryolite as raw material, but natural or impure, which needs to be refined. First, the crude product is crushed, removed by flotation and other methods, and then chemically refined to improve its purity.

The third method is to use sodium aluminate (NaAlO _ 2), hydrofluoric acid (HF) and sodium carbonate as raw materials. Under suitable reaction conditions, combine all substances. First react with hydrofluoric acid and sodium aluminate, then add sodium carbonate, and adjust the reaction temperature, time, material ratio, etc., to promote the formation of cryolite. The reaction process may involve multiple steps and needs to be carefully controlled.

The fourth method, the by-products of the electrolytic aluminum industry can also be used as a source. In electrolytic aluminum smelting, there are by-products containing fluorine, etc., which can be recycled to produce cryolite after proper treatment, separation, and purification. This is also a good way to make the best use of materials. Each method has its own advantages and disadvantages. In actual production, we should choose the best one based on factors such as the availability of raw materials, cost, and product quality.

What are the precautions for Trisodium hexafluoroaluminate during use?

In the case of trisodium hexafluoroaluminate, which is commonly known as cryolite is also. When using, there are several important things that must not be ignored.

First safety protection. This substance is toxic to a certain extent. If it is inadvertently inhaled, it may cause respiratory discomfort, or even damage the lungs. Therefore, when operating, it is necessary to wear appropriate protective equipment, such as masks and gloves, and act in a well-ventilated place to prevent inhalation or skin contact.

The second time is related to preservation. It needs to be placed in a dry and cool place to prevent moisture. Because the cryolite is exposed to water or moisture, it is easy to deteriorate and affect its performance. If it is not stored properly, or the appearance of agglomeration, it is difficult to disperse evenly during use, which is not conducive to its effectiveness.

Furthermore, the amount of usage also needs to be precisely controlled. In metallurgy and other industries, the amount of its dosage has a huge impact on the smelting effect. If the dosage is too small, it is difficult to achieve the expected effect of melting; if the dosage is too large, it will increase the cost, or cause other adverse reactions. Therefore, it must be accurately calculated according to the specific process requirements to determine the appropriate dosage.

In addition, in terms of environmental impact, although cryolite plays an indispensable role in a specific process, the treatment of its waste should also be prudent. If it is disposed of at will, elements such as fluorine may pollute soil and water sources, endangering the ecological environment. Therefore, it is necessary to properly dispose of waste in accordance with environmental protection regulations to reduce its harm to the environment.