The formation of glass, how glass is formed

A substance that is solid at room temperature melts after reaching a certain temperature and becomes a liquid state, which is called a molten state.

It is also in liquid form, but it is unstable at room temperature.

The melt can be cooled and solidified to obtain an amorphous solid, or a crystalline solid can be obtained.

For example, rocks melted at high temperatures, paraffin wax that becomes porridge when heated, and molten steel used in steelmaking are all molten products.

At room temperature, a solid substance melts after reaching a certain temperature, and the internal structure of the substance changes from a crystalline state to a liquid state, which is called melting. A substance in a molten state is called a molten substance. What we can see in our lives must be substances with very low melting points, and substances with a general melting point of room temperature are rare.

Glass was originally formed by the solidification of acidic rocks ejected from volcanoes. Around 3700 B.C., the ancient Egyptians had already made glass ornaments and simple glassware, when there was only colored glass, and about 1000 B.C., China made colorless glass. In the 12th century AD, commercial glass appeared and began to become an industrial material.

In the 18th century, in order to meet the needs of the development of telescopes, optical glass was produced. In 1873, Belgium was the first to produce flat glass. In 1906, the United States produced a flat glass lead-in machine.

Since then, with the industrialization and large-scale production of glass, glass for various purposes and various properties has been introduced. In modern times, glass has become an important material in daily life, production and in the field of science and technology.

More than 3,000 years ago, a European Phoenician merchant ship, laden with the crystalline mineral "natural soda", sailed on the Belus River on the Mediterranean coast. Due to the low tide of the sea, the merchant ship ran aground.

So the crew took to the beach. Some crew members also brought cauldrons, firewood, and used a few pieces of "natural soda" as a support for the cauldron to cook on the beach.

After the crew finished eating, the tide began to **. They were about to pack up and board the ship to continue sailing, when suddenly someone shouted, "Come and see, everyone, there is something bright and shining in the sand under the pot!" ”

The crew brought these glittering things to the ship and studied them carefully. They found that there was some quartz sand and melted natural soda stuck to these shiny things. It turned out that these glittering things were the natural soda that they used to make the stand for the pot when cooking, and under the action of the flame, the crystals produced by chemical reaction with the quartz sand on the beach, this is the earliest glass.

Later, the Phoenicians made a fortune by mixing quartz sand with natural soda and melting it in a special furnace to make glass balls.

Around the 4th century, the Romans began to apply glass to windows and doors. By 1291, glass-making technology in Italy was well developed.

Our country's glass-making technology must not leak out, and all the craftsmen who make glass are concentrated together to produce glass! ”

In this way, Italian glassmakers were sent to produce glass on an isolated island, from which they were not allowed to leave for the rest of their lives.

In 1688, a man named Naf invented the process of making large pieces of glass, and from then on, glass became an ordinary object.

The glass we use today is made of quartz sand, soda ash, feldspar and limestone at high temperatures.

An amorphous solid material obtained by the gradual increase in viscosity of the melt during cooling. Fragile and transparent. There are quartz glass, silicate glass, soda-lime glass, fluoride glass, etc.

It usually refers to silicate glass, which is made of quartz sand, soda ash, feldspar and limestone as raw materials, which is mixed, melted and homogenized at high temperature, processed and formed, and then annealed. It is widely used in construction, daily use, medical, chemical, electronics, instrumentation, nuclear engineering and other fields.

1. Glass is formed by melting sand, sodium carbonate and calcium carbonate together and cooling the brigade to a solid state.

2. Glass is a relatively transparent solid substance, which forms a continuous network structure when it is slowly melted in volcanic town, and the viscosity gradually increases and hardens without crystallization during the cooling process.

3. The main component of ordinary glass chemical oxide is silicon dioxide. Lack of mold.

1. Glass is formed by melting sand, sodium carbonate and calcium carbonate together and cooling to a solid state.

2. Glass is a relatively transparent solid skin substance, which forms a continuous network structure when the fibre melts the source limb, and the viscosity gradually increases and hardens without crystallization during the cooling process.

3. The main component of ordinary glass chemical oxide is silicon dioxide.

Although humans have been making glass since before 400 B.C., it wasn't until the 20th century that there was a breakthrough in how glass was made. Although there are thousands of formulations, there are three main ingredients: formers, fluxes and stabilizers.

The function of the former is to form the structure of glass, the main ingredient is silica, and there are boron oxide, phosphorus oxide, etc. Mixing fluxes and formers lowers the melting point of the former for processing and formation. Common fluxes are barium oxide and sodium oxide.

The function of the stabilizer is to make the formation of stable glass, the common stabilizers are calcium oxide and alumina, and calcium oxide mostly comes from calcium carbonate heating. In addition to these three basic materials, modern special glass also has some raw materials that are used in small quantities as colorants or clarifiers, or make glass have special uses, such as gold and copper in colloidal state can be used as colorants, and antimony and arsenic can be used as clarifiers.

Most of modern glass is sodium and lime glass, which is used in the production of flat glass, various containers and light bulbs. The most used is silica, which is often mixed with limestone and sodium carbonate in different proportions.

In glass factories, the mixed raw materials are first poured into storage tanks. Then, the ingredients are heated again until they melt to a white heat. The glass is then subjected to appropriate treatment, such as pressing two heavy rollers into flakes and pouring them onto a steel table to make lithographic glass.

The glass is made of crystal sand.

The raw material for making glass is crystal sand, and the main chemical components are silica and other oxides. If it is ordinary glass, then the raw materials for making glass are generally sand, sodium carbonate, calcium carbonate, etc., and some manufacturers will use a mixture of sodium sulfate and carbon instead of sodium carbonate. If some metal oxides or salts are mixed into ordinary glass, it can be made into colored glass.

Properties of glass:

Isotropic, the molecular arrangement of glass is irregular, and its molecules are statistically homogeneous in space. Ideally, the physical and chemical properties of homogeneous glass (such as refractive index, hardness, modulus of elasticity, coefficient of thermal expansion, thermal conductivity, electrical conductivity, etc.) are the same in all directions.

There is no fixed melting point, because glass is a mixture, amorphous, so there is no fixed melting and boiling point. The transformation of glass from a solid to a liquid takes place within a certain temperature region (i.e., the softening temperature range) and, unlike crystalline substances, does not have a fixed melting point. The softening temperature range is from tg to t1, tg is the transition temperature, t1 is the liquidphase temperature, and the corresponding viscosities are 10dpa·s and 10dpa·s, respectively.

Metastability, glassy substances are generally obtained by the rapid cooling of the molten body, when the viscosity increases sharply during the cooling process, the particles do not form crystals in a regular arrangement, and no latent heat of crystallization is released, therefore, the glassy substances contain higher internal energy than the crystalline substances, and its energy is between the molten state and the crystalline state, which belongs to the metastable state.

From the mechanical point of view, glass is an unstable high-energy state, for example, there is a tendency to transform into a low-energy state, that is, there is a tendency to crystallize, so glass is a kind of solid material with a good grasp of metastability.

Gradual reversibility, glass [silicate non-metallic materials] The process of glass from the molten state to the solid state is gradual, and the changes in its physical and chemical properties are also continuous and gradual. This is markedly different from the crystallization process of the melt, which inevitably leads to the emergence of new phases, and many properties are abruptly abrupt near the crystallization temperature point. <>