How do you burn ceramics? What are the chemical changes in it

The hardening of the soil in ceramics is the cause of chemical changes.

The chemical formula of the main component of ceramics is SiO2

At high temperatures, the solid particles of ceramic green billet are bonded to each other, the grains grow, the voids (pores) and grain boundaries gradually decrease, and through the transfer of matter, the total volume shrinks, the density increases, and finally becomes a dense polycrystalline sintered body with a certain microstructure, this phenomenon is called sintering.

This process involves both physical and chemical changes.

Porcelain is made of clay, quartz and feldspar and other natural mineral raw materials according to different formulas, through processing, molding and firing, its chemical composition depends on the natural raw materials and formula, different regions of different kilns of ancient ceramics due to the different raw materials used, different formulas and different firing processes, the chemical composition, microstructure and physical properties of the glaze will have their own characteristics. If the ceramic specimens with reliable stratigraphic age at the time of excavation at different kiln mouths are collected for systematic research, the accumulated data such as chemical composition data (including the content of primary and secondary elements and trace elements) are established in a database, and the data are processed by appropriate processing methods, such as multivariate statistical analysis, to find out the laws with characteristic significance. The chemical composition, microstructure, physical properties and firing process of the ceramics to be identified are studied, and the chemical composition data are compared with the chemical composition data of ancient ceramics with known kiln mouths and ages, and then the information of microstructure, physical properties and firing process can be used to identify the ceramics.

Ceramics are mixtures, and the composition is particularly numerous and complex, and the composition varies according to the origin of the ceramic. Its main components are silica and silicates (aluminum silicate, calcium silicate, etc.).

Yes. Clay firing into ceramics is a chemical change; Because firing ceramics is heated with clay at high temperatures, there is some oxidation process during the firing process, and during the oxidation process, the minerals in the clay will undergo chemical reactions.

The process of firing porcelain is the process of the minerals in the porcelain clay from random mixing to the formation of chemical bonds to become partial crystallization, and there is a production of new substances, so it is a chemical change.

The millennium kiln fire, endlessly, after dozens of processes of finely carved porcelain billet, in the kiln to withstand the high temperature of 1,000 degrees of smelting, just like an ugly duckling about to reach a beautiful swan. There are gas kilns, electric kilns (heating methods), etc.

Although ordinary clay also contains oxygen, silicon, calcium, aluminum, iron and other substances of silicate, but more large quantities of silicon-aluminum oxide in clay, fine particles, strong plasticity, good bonding, excessive thixotropy, suitable shrinkage, high refractory, than a general clay, kaolinite, montmorillonite, illite and diaspore content is higher.

The firing temperature is about 800 to 1000 for pottery and 1200 to 1400 for porcelain.

At 500 to 700, the quartz crystal form is transformed; At 700 to 1000, the substances in the clay will undergo oxidation reaction and decomposition reaction, and from 1200 to 1400, there will be a reduction reaction. Among them, the decomposition of iron sulfide, carbonate, sulfate, iron hydroxide and the oxidation of organic matter make the original substance glaze, that is, from clay to porcelain.

In the reduction process, for example, iron oxide will be reduced to ferrous oxide, which will change from brown to cyan, which will make the color of the fired porcelain different from the carcass before the furnace. Finally, it goes through the quenching, slow cooling, and fast cooling stages to completely finalize.

Firing porcelain is a chemical change. Ceramics are materials and various products made by crushing and mixing, forming and calcining clay as the main raw material and various natural minerals. The process of firing porcelain is the process of random mixing of minerals in porcelain clay to forming chemical bonds and becoming partial crystals.

That is to say, reactions such as dehydration, deoxygenation, and the formation of inorganic polymers are all chemical reactions.

The following items can be called porcelain: 1. The tire material of porcelain must be porcelain clay. The composition of porcelain clay is mainly kaolin and makeup clay, and contains feldspar, quartz stone and mullite components; Low iron content.

After high-temperature firing, the tire color is white, transparent or translucent, and the carcass water absorption rate is less than 1%, or no water absorption.

2. The carcass of porcelain must be roasted at a high temperature of 1200 1300 to have the physical properties of porcelain. The porcelain clay is different in different places, and the firing temperature is also different, so the sintering shall prevail.

3. The glaze applied to the surface of the porcelain must be a vitreous glaze fired together with the porcelain at high temperature.

The process of pottery firing is a chemical change. Pottery refers to the clay as the fetus, after hand kneading, wheel making, molding and other methods of processing and molding, in the high temperature of about 1000 1200 degrees of baking into the article, the production process of pottery can be divided into raw material processing (including mud and glaze), mud plastic, glaze and calcination four major processes, the production of pottery in China has a long history of more than 11,700 years.

Pottery kiln

One of the most critical processes in making pottery is firing it in a kiln. In pottery kilns, the high temperatures generated by the wood fuel cause a chemical reaction in the clay, which leads to a change in the composition, properties and color of the green body.

The structure of the pottery kiln determines the firing temperature of the pottery to a large extent, and the more reasonable the structure, the higher the firing temperature, and the more solid and durable the pottery will be; The sealing condition of the pottery kiln can not only affect the temperature in the kiln, but also cause an oxidative or reduced firing atmosphere, which can affect the color of the pottery. Therefore, the pottery kiln is the main indicator to measure the level of pottery technology.

1. Clay firing into ceramics is a chemical change; Because the firing of ceramics is heated with clay at high temperatures, there is some oxidation process in the firing process, and during the oxidation process, the minerals in the clay will undergo a chemical reaction and new substances will be generated.

2. Chemical reaction refers to the process of cracking molecules into atoms, and the atoms are rearranged and combined to form new substances, which is called chemical reactions. In the reaction, it is often accompanied by luminescence, heat, discoloration, and the formation of precipitate, etc., and the basis for judging whether a reaction is a chemical reaction is whether the reaction generates new substances.

3. A physical reaction refers to a change in the state or form of existence of a substance, but no change in the properties of the substance itself. All the distinction between chemical reactions and physical reactions is to see whether there is a new substance formed, and if there is a new substance, it is a chemical reaction, and if there is not, it is a physical reaction. The process of firing clay into ceramics involves the formation of new substances, so the process of firing clay into ceramics is a chemical reaction.

To determine whether it is a physical or chemical change, it is necessary to see whether new substances are produced.

The phenomena of chemical change are: combustion [such as: iron smelting, steelmaking, porcelain burning], ** [gunpowder] and so on.

Therefore, firing pottery is a chemical change.

Note: Firing pottery is related to combustion, so it is a chemical change. The chemical changes associated with combustion are general

There are both physical and chemical changes, and the main change is the change in crystal morphology.