How porcelain is made. Everything about porcelain: types, classification, painting. Individual orders, busts and fight

porcelain vase

Porcelain tableware has always been highly valued and can last for decades, and the presence of porcelain dishes has always been considered a sign of wealth. What is porcelain made from? What types of porcelain are there? How do they do chinaware?

Composition of porcelain

Porcelain is usually obtained by high-temperature firing of a coarse mixture of kaolin, quartz, feldspar and plastic clay (mainly kaolin, with inclusions of chromophore ions).

Depending on the composition, porcelain is divided into hard and soft. The hardness of finished porcelain is the same, and they got such names because more liquid phase is formed during the manufacture of soft porcelain.

The composition of hard porcelain includes:

47-66% kaolin,
25% quartz,
25% feldspar.

Hard porcelain is richer in kaolin (alumina) and poorer in fluxes. To obtain the necessary translucency and density, it requires a higher firing temperature from 1400 °C to 1460 °C.

The hardest porcelain is bone china, which contains up to 50% bone ash, as well as kaolin, quartz, etc., and which is distinguished by its special whiteness, thin-walledness and translucency.

Hard porcelain is usually used in technology (electrical insulators) and in everyday life, more often as dishes.

Soft porcelain consists of:

25-40% kaolin,
45% quartz,
30% feldspar.

The firing temperature usually does not exceed 1300-1350 °C.

Soft porcelain is used primarily for the manufacture of artistic products.

Basically, porcelain is glazed. White, matte, unglazed porcelain is called biscuit.

Porcelain is painted in two ways:

underglaze painting,
overglaze painting.

Porcelain painting

From the names it is clear how painting is applied to porcelain. When painting underglaze porcelain, paints are applied to unglazed porcelain. Then the porcelain product is covered with transparent glaze and gently fired at temperatures up to 1350 degrees.

Overglaze painting is applied to glazed unpainted white porcelain and then fired in a muffle furnace at a temperature of 780 to 850 degrees.

During firing, the paint is fused into the glaze, leaving behind thin layer glaze. Paints after a good firing shine (except for special matte paints used only for decorative purposes), do not have any roughness and in the future better resist the mechanical and chemical effects of acidic food products and alcohol.

The color palette of overglaze painting is richer than that of underglaze painting.

Now, using chinaware in everyday life, you will know what it is made of.

Introduction

Porcelain is the main representative of fine ceramics. The characteristic features of porcelain are white with a bluish tint, low porosity and high strength, thermal and chemical resistance and natural decorative effect. Its features are determined by the chemical composition and structure of the crock, which depend on the purpose of the product, the conditions of their operation and the requirements for them.

Porcelain has high mechanical strength, chemical and thermal resistance, electrical insulating properties and is used for the manufacture of high-quality tableware, artistic, decorative and sanitary ware, electrical and radio engineering parts, corrosion-resistant chemical technology devices, low-frequency insulators, etc.

Porcelain is usually obtained by high-temperature firing of a fine mixture of kaolin, feldspar, quartz and plastic clay (such porcelain is called feldspar). The term "porcelain" in the English literature is often applied to technical ceramics: zircon, alumina, lithium, calcium boron and other porcelain, which reflects the high density of the corresponding special ceramic material.

Porcelain is also distinguished depending on the composition of the porcelain mass into soft and hard. Soft porcelain differs from hard porcelain not in hardness, but in the fact that when firing soft porcelain, more liquid phase is formed than when firing hard porcelain, and therefore the risk of deformation of the workpiece during firing is higher.

Hard porcelain is richer in alumina and poorer in fluxes. To obtain the necessary translucency and density, it requires a higher firing temperature (up to 1450 °C). Soft porcelain is more diverse in chemical composition. The firing temperature reaches 1300 °C. Soft porcelain is used mainly for the manufacture of art products, and hard porcelain is usually used in technology (electrical insulators) and in everyday life (dishes).

One of the types of soft porcelain is bone china, which includes up to 50% bone ash, as well as quartz, kaolin, etc., and which is distinguished by its special whiteness, thinness and translucency.

Porcelain is usually glazed. White, matte, unglazed porcelain is called biscuit. In the era of Classicism, biscuits were used as inserts in furniture products.

PRODUCTION PROCESS

Preparation of raw materials

The composition of the ceramic mass and the method of its preparation are determined based on the purpose of the product, its shape and type of raw material. The purpose of the preparation of raw materials is the destruction of the natural structure of materials to the smallest particles in order to obtain a homogeneous mass and accelerate the interaction of particles in the process of porcelain formation. It is carried out mainly by a plastic method, which provides a uniform composition of the mass.

Plastic materials (clay, kaolin) are dissolved in water in paddle mixers. The resulting mass in the form of a suspension is passed through a sieve (3600 - 4900 holes per 1 cm2) and an electromagnet to remove large inclusions and ferruginous impurities.

Weakening materials and fluxes are sorted, freed from foreign and harmful impurities. Quartz, feldspar, pegmatite and other components are fired at a temperature of 900-1000°C. In this case, quartz undergoes polyform changes, as a result of which it cracks. This, firstly, makes it easier to grind, and secondly, it makes it possible to remove pieces contaminated with ferruginous impurities, since during firing, quartz with impurities of ferruginous compounds acquires a yellow-brown color.

Stony materials, including porcelain batt, are washed, subjected to crushing and coarse grinding on runners, and then sieved. Fine grinding is carried out in ball mills with porcelain or uralite balls. To intensify grinding, a surface-active additive is introduced into the mill - sulfite-alcohol bard (from 0.5 to 1%), which, filling microcracks, has a kind of wedging effect. Grinding is carried out to a residue of 1-2% on a sieve with 10,000 holes per 1 cm2.

Plastic and emaciated materials, fluxes and porcelain batt are thoroughly mixed in a propeller-type mixer. A homogeneous mass is passed through a sieve and an electromagnet and dehydrated in special filter presses or vacuum filters. The resulting plastic mass with a moisture content of 23-25% is sent for two weeks for aging in a room with high humidity. During aging, oxidative and microbiological processes, hydrolysis of feldspar and the formation of silicic acid occur, which contributes to the loosening of the mass, further destruction of the natural structure of materials and an increase in the plastic properties of the mass. After aging, the mass is processed on mass grinders and vacuum presses to remove air inclusions, as well as plasticity and other physical and mechanical properties necessary for the formation of products.

Types of porcelain

Depending on the composition of the porcelain mass and glaze, hard and soft porcelain are distinguished. Some intermediate type is represented by the so-called bone china.

hard porcelain contains mainly two starting materials: kaolin and feldspar (most often in combination with white mica; melts relatively easily). Quartz or sand is added to these basic substances. The properties of porcelain depend on the proportion of two main substances: the more kaolin its mass contains, the more difficult it is to melt and the harder it is. This mixture is ground, kneaded, milled and then dried to the extent of a pasty state capable of taking shape. A plastic mass appears, which can either be cast in molds or turned on a potter's wheel. Finished objects are fired twice: first without glaze at a temperature of 600-800 degrees C, then with glaze - at 1500 0 C. Feldspar or pegmatite are used as fluxes. Cover hard porcelain with hard glaze. Thin varieties are covered with lime-free spar glaze, so the products are matte, milky-cream in color. But simpler varieties are covered with a completely transparent lime glaze. Glaze and porcelain mass consist of the same substances, only in different proportions. Thanks to this, they are connected and the glaze can no longer be beaten off or peeled off.

Hard porcelain is characterized by strength, strong resistance to heat and acids, impermeability, transparency, conchoidal fracture and, finally, a clear bell sound. Invented in Europe, in 1708 in Meissen by Johann Friedrich Bötger.

soft porcelain , also called art or frit, consists mainly of mixtures of vitreous substances, the so-called frits, containing sand or flint, saltpeter, sea salt, soda, alum and crushed alabaster. After a certain melting time, marl containing gypsum and clay is added to this mass. In principle, this means that we are talking about a fused vitreous substance with an addition of clay. All this mass is ground and filtered, bringing to a plastic state. The molded object is fired at 1100-1500°C, becoming dry and non-porous. The glaze is predominantly made of glass, that is, of a fusible substance rich in lead oxide and containing, in addition, sand, soda, potash and lime. Already glazed products are subjected to secondary firing at 1050-1100°C, when the glaze is combined with the shard. Compared to hard, soft porcelain is more transparent, the white color is even more delicate, sometimes almost creamy, but the heat resistance of this porcelain is lower. The fracture is straight, and the unglazed part is granular in the fracture. The initial European porcelain was mostly soft, which is exemplified by the fine and highly valued products of the Sevres. It was invented in the XVl century in Florence (Medici porcelain).

Bone china represents a well-known compromise between hard and soft porcelain. Its composition was discovered in England and its production began there around 1750. In addition to kaolin and feldspar, it contains lime phosphate from burnt bone, which makes smelting easier. Bone china is fired at 1100-1500°C. So, we are talking essentially about hard porcelain, but one that is made softer by mixing burnt bone.

Its glaze is basically the same as on soft porcelain, but contains, in addition to lead oxide, a certain amount of borax for better connection with the shard. With appropriate incandescent heat, this glaze melts and is firmly connected to the shard. According to its properties, bone china occupies an intermediate position between hard and soft porcelain. It is harder and harder than soft porcelain and less permeable, but it has a rather soft glaze in common. Its color is not as white as that of hard porcelain, but whiter than that of soft porcelain. Bone china was first used in 1748 at Bow by Thomas Fry.

From the above, we can conclude; that the main ones for the manufacture of porcelain, there are three types that differ in composition, firing temperature and are used for different types products. Also, for each type, its own glaze is made.

PORCELAIN PRODUCTION TECHNOLOGY

. Porcelain production

The production process for the manufacture of ceramic products consists of several stages:

preparation of raw materials;

mass preparation;

product formation, firing;

glazing and decor.

The preparation of raw materials consists in cleaning the raw materials from impurities, thorough grinding, sifting, drying, etc. The preparation of the mass consists of mixing the raw materials in certain proportions and mixing the mixture with water until a homogeneous liquid porcelain mass is obtained. The mass is passed through a sieve, cleaned (with an electromagnet) from iron impurities and dehydrated (on filter presses or vacuum presses) to obtain a forming dough.

free molding on a potter's wheel;

plastic molding by hand imprint in the mold;

plastic molding in a rotating plaster mold using a forming template or roller;

· Formation of the vessel by the method of circular molding. Molding by slip casting in plaster molds;

production of ceramic products by a combination of several molding methods.

The method of free molding of ceramic products on the potter's wheel consists in the mechanical action of the potter's hands on the clay blank in the form of plastic dough. First, the master prepares the potter's wheel for work. The first stage is the primary processing of the workpiece. Then the internal cavity of the product, the edges of the workpiece, and again the internal cavity are formed. After that, the master pulls the workpiece to the desired height. During all these operations, he rotates the potter's wheel with his foot or with a drive mechanism. The process ends with finishing the outer surfaces, trimming the bottom, and drying. During drying, the product can be decorated with stucco details, seals, stamped moldings.

Plastic molding by hand imprint is carried out using plaster molds. Forms can be open and detachable; open ones are used for molding flat products; detachable - in the development of products on three-dimensional models of complex shapes.

Plastic molding in a rotating plaster mold using a template or roller is as follows. The form, which opens into two halves, is installed in the assembled form in the rotating bowl of the machine. A lump of clay is fed into the inner cavity of the mold, calculated on the volume of the manufactured product. A forming template is lowered into the mold cavity, which evenly distributes the clay mass in the inner side of the mold, after which it is lifted and removed from the mold. Then the form with the product is removed from the setting machine, dried, opened, the product is removed and further processing is continued (attachment of parts - spouts, handles, covers and other additional mounts).

Molding by the method of slip casting into plaster molds is based on the property of gypsum to absorb moisture, and the ability of clay to transfer from a liquid slip to a plastic dough state when the humidity decreases. Products are formed as follows. The slurry is poured into the inner cavity of the gypsum mold, as a result of which moisture is redistributed between the slurry, which releases moisture, and the gypsum mold, which absorbs this moisture. After redistribution of moisture on the inner working surface of the gypsum mold, a layer of clay mass is formed from the slip, turning into a state of plastic dough. When the form has "gained" the specified thickness of the layer of clay, the slip is poured out of the inner cavity of the mold, and the layer of clay on the inner surface of the mold remains. This layer of thickened slurry is a molded hollow pottery raw material. As it dries, the raw material in the form, decreasing, separates from its walls.

The manufacture of ceramic products by a combination of several molding methods makes it possible to obtain products of complex shape. The combination of plastic molding in a rotating plaster mold with a metal template or roller with slip casting and mounting of attachments is widespread in the production of teapots, sugar bowls, cups, decanters, bowls and other porcelain and earthenware products consisting of a body and individual parts. After molding, the products are dried in air and fired.

What is porcelain made from?

PORCELAIN: The composition from which the best stoneware is made: china clay, kaolin, weathered feldspar with quartz.
V.Dal
Over a thousand years ago, people in China drank from jade cups. They were very expensive.
After many years of searching and many failures, Chinese potters made a material that surpassed jade in its qualities, turned out to be more accessible and easier to process.
It was porcelain. For a long time it was called "imitation of jade". "Chinese secret" was the secret of raw materials. In the province of Jiangxi, there were huge reserves of "porcelain stone" - a rock consisting of quartz and mica. Porcelain mass was made from briquetted powder of "porcelain stone" (pe-tun-tse) and kaolin, which gave the product whiteness. Kaolin was abundant in the same province. The mass was "aged" for more than a dozen years, so that they acquired plasticity. The glaze was made up of several layers of different transparency, obtaining a special, matte sheen.
Not only dishes were made of porcelain (the imperial court received 31,000 dishes every year, 16,000 plates with dragons, 18,000 cups), but also benches, gazebos, and in 1415 they built the Nanking Pagoda. Porcelain vessels were in China and musical instruments: tapping with a thin stick on their walls gave rise to a melody.
All porcelain can be divided into three main groups - Oriental porcelain, European hard porcelain and soft porcelain (semi-porcelain). The main component of Oriental and European hard porcelain is kaolin (non-melting china clay and feldspar). European porcelain has more kaolin than Eastern porcelain and requires a hotter fire when fired. This gives him transparency, but in such a fire all colors burn out, except for blue. Therefore, European porcelain has to be painted on top of the glaze, while Oriental porcelain allows the use of a number of colors for underglaze painting.
Hard porcelain, or simply porcelain, is a homogeneous, white, strongly ringing, hard and difficult-melting, with a slight thickness, a very transparent mass, in a break it is fatty-shiny, conchoidal, fine-grained; hard porcelain consists mainly of kaolin and feldspar, with an admixture of quartz, lime, etc., and is covered with a hard glaze.
Soft porcelain consists of an incompletely molten, vitreous, fine-grained mass, with a lead, crystal-like, siliceous glaze. The fusible glaze, which makes it similar in appearance to Chinese porcelain, allows for thick writing and much more delicate tones than hard porcelain. The composition of English soft porcelain (bone china) includes burnt bone, phosphate salts, kaolin, etc. It occupies a place between the stone mass and hard porcelain, resembles white alabaster and is extremely transparent.

Porcelain is the finest ceramic of a white translucent color with a bluish tint, used for sculpting dishes and sculptures.
It has the second name "singing dishes", hitting the edges of which, you can hear a melodic ringing, as if thousands of bells are hidden at the bottom of it.
In our time, such products are objects of good taste, an attribute of luxury, it is always an "timeless classic" that impresses not only as a table setting item, but also of great value.

The basis in production is porcelain mass, consisting of koalin clay, feldspar and quartz.
Due to the high temperature regime of firing, the material becomes dense, without pores. Products acquire thermal strength and at the same time lightness, do not have smudges and seams.

China is the origin of porcelain.
During the reign of the Tang Dynasty in the 6th-7th centuries BC, dishes were made mainly from jade, which was considered a rather rare and expensive stone, and cheap clay and wood were short-lived.

It took several decades until it was found in Jiangxi rock, formed from quartz and mica, called porcelain stone.
The first products were elongated jugs with relief decor in blue and greenish tones.
In the 9th century BC, China becomes unofficially the "porcelain capital".
Mass production of tableware and export to Europe and East Asia begins.
The secret of production was kept in the strictest confidence for many centuries, which the German chemist Böttger managed to reveal.
Thanks to the deposits of white clay in the vicinity of Saxony, he made a bowl and presented it to King Augustus the Strong.
From that moment, “Saxon porcelain” also sounded. The secret has been revealed.

Classification

There are three types of porcelain: hard, bone and soft.
They differ in the main components and temperature regimes of firing.
Porcelain production began precisely with a solid look.

hard porcelain

It consists mainly of a large part of koalin and a smaller part of feldspar, to which quartz and sand are added. Thanks to this proportion, the dishes have good strength, value and popularity in production.
It is subjected to double firing. First, at a low temperature of 900 degrees, then when applying glaze - 1350-1450 degrees.
At the same time, each stage undergoes strict quality control. Sometimes exceeding the marriage threshold of 20-25%.
This type of porcelain has several purposes:

economic - tea, table and kitchen utensils;
artistic - vases, figurines, bas-reliefs, dishes;
industrial - electrical insulating materials;
chemical - glassware, parts for the chemical and perfume industries.

Bone china

Intermediate, is considered much more valuable than hard porcelain. It is obtained by adding bone ash to the bulk.
It is also subjected to double firing, but first at a high temperature of 1200-1300 degrees, then the temperature gradually decreases for better hardening to 1050-1100 degrees. Due to this, it has complete absence since.
Products are distinguished by a special white color, belong to the elite category.

soft porcelain

As a result of attempts to create an analogue of a hard type of ceramics, it was first invented in Europe.
Products are creamy in color. Consists of sand, saltpeter, crushed alabaster and clay.
Passes a single heat treatment at 1050-1100 degrees. The ceramic mass does not completely sinter, because of this it has a porous surface, low heat resistance, high sensitivity to temperature changes, the glaze is easily subjected to mechanical stress.
Used in the production of art products.
This porcelain has several types.

French is very similar to Chinese. Perfect for painting and painting with gilding of interior items.

English - due to the addition of phosphate salt to the composition, it has a structure similar to white alabaster. Ideal for jewelery work.

German - consists of clay, externally and in quality is close to glass. Due to the low firing temperature, painting with paints acquires a beautiful sheen.

To obtain the desired surface shape, as well as the use various ways decoration, several varieties of soft porcelain are used.

Feldspar - contains in the base a high content of feldspar 50%, quartz sand - 20% and white clay - 30%. One stage of thermal firing takes place, thanks to which the material has a high density. It is characterized by heavy weight, low strength and low cost. It is convenient when drawing a list on products.
High feldspar - has a high content of quartz 45% and feldspar 40%, the smallest amount of clay - 15%. Because of such proportions, it belongs to the elite category.
As well as feldspar porcelain, it is subject to low firing temperatures, which open up great opportunities for decoration.
Frit - one of the most inexpensive types of ceramics.
Due to the addition of an alloy of salts with glass (frit) to the clay, the lowest firing of all possible firings takes place. It has mechanical strength, thermal stability and a high degree of protection against chemical attack.
Widely used in sculpting sculptural compositions.

Biscuit porcelain

Another type of porcelain, the main difference of which is that it underwent only primary firing at a temperature of 800-1000 degrees. This results in a rough porous structure. The material is more similar in structure to high-quality marble. Most often, the biscuit is not glazed, leaving a matte surface, reminiscent of velvet skin. The birthplace of biscuit is the French town of Sevres. The first masters began to work in this technique in the second half of the 18th century. Due to the fact that porcelain is not protected by glaze, it is not used for the production of tea and dinner sets. It produces magnificent figurines, vases, sculptures and elements of furniture decor.

For more than one century, dishes and interior items made of porcelain have had distinctive features in the painting technique.

Underglaze is a rather complicated and time-consuming painting and expensive.
It is typical mainly for Chinese antique porcelain. The drawing is applied with a pen or brush before firing, so the master needs to accurately calculate the proportions of dyes and paints in order to prevent the drawing from dissolving in the glaze. Be sure to add aluminum oxide or kaolin.
Spray guns and special underglaze pencils are also used in this technique.
Overglaze - the simplest painting in the product, making it affordable.
Paints must have thermal and chemical resistance, as they are subjected to firing in a muffle furnace after application to the glazed surface.
This painting is most often used in the design of services.

Decor

It can be mini-figures of people and animals, flowers, curls, elements of church symbols and much more.
Individual elements, also made of porcelain, are fixed with adhesives.
Thanks to such additions, the products acquire a sophisticated look.
The dishes become more elegant and fragile.

Conclusion

Porcelain will forever remain associated with history, tradition and art.
It is no coincidence that it is called "white gold".
This is an ageless value that can be stored for centuries and passed down through generations.
Nowadays, there are many factories for the production of porcelain, not only in Russia, but also abroad.
Porcelain products are able to create warmth and comfort in every home.

Porcelain production is a fine art, chemistry, magic, it is not for nothing that the material is called “white gold”. There were times when table sets from it were valued more than precious metals, were considered the privilege of crowned persons.

History of appearance

The secret of porcelain mass production has been a secret for a long time. China is considered the birthplace of the material, where it appeared in 620. For almost a thousand years, Chinese craftsmen remained monopolists, carefully guarding the recipe and the secret of making kaolin products.

Meanwhile European masters experimented to get the optimal formula. As a result, in 1708, two German scientists, Bettger and Tschirnhaus, succeeded in this. They managed to obtain high-quality raw materials for porcelain. Thus began his era in Europe.

In the same year, 1708, the first manufactory was opened in Dresden, producing unglazed cutlery. Two years later, the craftsmen presented the products to the German king - he approved them. And soon German services conquered other countries.

A detailed description of raw materials and technology appeared later, after 20 years. Gradually, production was mastered in France, England, Russia.

Description

In the classic version, this is a translucent material, thin glazed ceramics. Its characteristic features:

white color with a blue tint;
high strength - it will not work to scratch the product with a sharp object;
low porosity;
resistance to chemical and temperature effects;
natural beauty.

Composition and preparation of raw materials

For the manufacture of porcelain, a mass is used, which includes:

50% kaolin;
25% quartz;
25% feldspar.

With such proportions, the mixture is white, with the required degree of transparency, plastic. Not every clay is suitable - only certain varieties.

The preparation of raw materials is necessary to destroy natural solid materials to the state of the smallest granules and obtain a homogeneous mass. To obtain a uniform composition, plastic kaolin is dissolved in water using paddle mixers.

Then the pre-prepared mass (it has the consistency of a suspension) is sieved through industrial sieves. Each sieve has 3500-5000 holes per 1 cm2. They have a built-in electric magnet that cleans the mixture from large metal impurities.

Feldspar and quartz are cleaned of impurities, after which they are fired in special furnaces. The firing temperature is 900-1000 degrees. During heat treatment, quartz cracks, it is easier to grind and clean it from iron compounds.

Cleaning from iron is a mandatory step, because if this is not done at finished products there will be a dirty brown tint.

For the most fine grinding, special additives are added to industrial mills. They are superficial, they do not affect the quality of porcelain products.

When a homogeneous mass is obtained, it is sieved again, then dehydrated in filter presses and sent for aging. The raw mass is aged in damp rooms for two weeks. During this time, it loosens, its plastic properties increase. Then air is removed from the raw material in vacuum presses and sent for the formation of blanks.

Molding

Porcelain production technology is a complex multi-stage process. This largely explains the high cost of products. For molding blanks, molds made of gypsum or PVC are used.

Molding is carried out in a semi-automatic or automatic way. A special roller and a rotating mold are used to roll out a layer of the same thickness.

Things of complex shape, having decorative and artistic value and complex configuration, are made by casting. For blanks, plaster or detachable molds are used.

Drying

When the future cup, vase, teapot, plate are molded, they need to be dried. The initial moisture content of the raw mass is 22-24%, and after drying, the indicator is reduced to 2-4%. This is necessary to obtain durable products, without internal cracks and deformation.

Drying consists of two stages:

Preliminary - the blanks are dried in molds to 15-16% moisture, after which they are removed from the molds.
Final - the blanks are dried without molds to 2-4% moisture.

Processing is carried out in special dryers, which greatly speeds up the process. Dried kaolin products are cleaned from seams, dirt, dust are removed and sent for firing.

Burning

The first firing is carried out at a temperature of 900 degrees and takes about 12 hours. Then the product is glazed and fired again.

The re-firing temperature is higher, starts from 1000 degrees - the exact figure depends on the type of porcelain, the technique of its manufacture.

Types of porcelain

The material is classified by manufacturing technique as:

solid;
soft;
biscuit;
bone.

Solid

It contains from 47 to 66% kaolin. Roasting takes place at a temperature of 1400-1600 degrees. Initially, there is less moisture in such raw materials - the workpieces are practically not deformed.

Bone

This type is considered the most durable, while it is valued for its thin, translucent walls. With apparent external fragility, it is more difficult to break it than the classic one.

Half of the composition of bone china is bone meal - hence the name.

Biscuit

Biscuit porcelain has a porous, rough structure that looks like marble. This feature is explained by the fact that the blanks undergo only primary firing at a temperature of 800 to 1000 degrees.

The matte texture looks so impressive that it is usually not covered with glaze. This technique is used to make vases, figurines, and other interior items. Biscuit porcelain dishes are not made.

Soft

The composition of soft raw materials includes less kaolin - 25-40%. At the same time, the amount of feldspar and quartz is increased - 45 and 30%, respectively. The kaolin mass is not so strong, but very plastic.

There are several varieties of soft porcelain:

Feldspar. It contains 50% spar and only 30% white clay. The material is dense, heavy, but not durable, so it is much cheaper than analogues. Fired once.
High feldspar. It differs from feldspar in a large amount of quartz - 45%. Specific gravity clay - only 15%. Products from it are considered elite, fired at a low temperature.
Frit - durable, resistant to thermal effects, chemicals, affordable. Fired at the lowest temperature. In addition to clay, the composition includes alloys of salts and glass. Frit mass is often used for sculpting figurines and other original things.

Soft kaolin mass was preferred by craftsmen Ancient China, and hard - European craftsmen.

painting

There are two types of painting: underglaze and overglaze.

In underglaze painting, paints are first applied to the product, and then the painted layer is covered with glaze. The glaze is transparent, gives an elegant shine to products, protects against microcracks, ultraviolet radiation, alkalis. Such dishes can be washed many times without compromising quality.

The overglaze technique is performed in the reverse order: first, the product is covered with glaze, and paint is already applied to it. The colors are bright, saturated, but eventually fade, fade.

For sets and accessories of mass production, drawings are applied using the decal technique. First, the drawing is printed on special paper, then it is glued onto a cup, tureen, plate and fired. The paper burns, and the colors are imprinted on the surface of the dishes.

Premium-class porcelain products are piece goods, hand-painted by craftsmen, decorated with gold and silver. The cost of work is high, but real works of art are obtained.

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