Such a thing as glass surrounds us everywhere: windows in a house or a car, aquariums, dishes, decor items, retorts and beakers in industry and medicine, even watches have it. Interesting Facts:
- It takes a million years for glass to decompose.
- During processing, glass retains all its qualities.
- The thickest sheet of glass is the screen aquariums in Sydney. Its thickness is 26 cm.
Modern production technologies make it possible to obtain glass with the most different characteristics and qualities:
- Household. It is used in Everyday life: crockery, glasses, decorative items.
- Technical. It is a very dense glass used in heavy industry.
- Construction. Showcases, stained-glass windows, windows are made from it.
- Bulletproof. It is used to improve the safety of buildings, cars, etc.
Today, looking at a tiny watch dial, we can think: which glass is better sapphire or mineral. We can choose materials of various shades for finishing our windows: blue, red, green or no color at all. Buy a matte white strict vase or a colorful bright freeform product from professional glassblowers. It is even strange for such popularity that very few people think of the question, how is glass made? What is needed for this?
What is glass made of
Not only the manufacturing process itself is curious, but also what glass is made of. There are usually only three ingredients at the base, and each of them has its own role in the creation process:
- Quartz sand is the base. Its melting point is 1700⁰С.
- Soda. It helps to reduce the melting point of sand by half and significantly simplify the manufacturing process.
- Lime. This component is essential for waterproofing. If it were not there, then we would not be able to put flowers in a vase, we would not drink tea from a glass, since water would simply dissolve such an alloy.
Glass making is a rather hot, laborious and dangerous process. First, all components are mixed and melted in a special furnace. After the grains of sand combine with each other, turning into a homogeneous mass, it is sent to a bath of molten tin (its temperature is above 1000⁰С). The glass mixture will float on the surface due to the difference in density of the materials. The less mass there is in the tin container, the thinner the sample will be. After that, the blanks are cooled on a special conveyor.
Curious in history:
- One of the oldest glass particles dates back to the 21st century. BC. Blue transparent raw glass has been found in southern Mesopotamia. Glassmaking was also practiced in Syria, Egypt and Phoenicia.
- For many centuries, glass from Venice was considered the most expensive. The masters produced unusually thin and beautiful products: dishes, jewelry, mirrors, costing fabulous money. For a very long time, Venice was a glass monopoly, and the secrets of craftsmanship were jealously kept. In the 13th century, production was even transferred to the island of Murano, and the craftsmen were forbidden to leave it under pain death penalty. Despite this, glassmakers were a special, rich and privileged caste. An unheard-of thing for that time: having married the daughter of such a master, the guy moved to his wife's family!
- One of the world leaders in production today is China, it controls a third of the world market. And in the period from the 14th to the 19th century, the country did not produce glass at all.
As long as there is glass, there are varieties of it, differing in color. What is blue, green or red glass made of? What allows you to change the shade of the material to create a beautiful stained glass window, vase or sculpture? It's all about adding different chemical compounds, most often oxides:
- The red color is imparted by the addition of iron oxide.
- purple and brown shades(it all depends on the quantity) - nickel.
- The bright yellow color is uranium.
- Shades of green - chrome and copper.
- Intense blue - cobalt.
By the way, another oxide - this time aluminum oxide is used to produce sapphire glass for watches. It is very hard, you can only scratch it with a diamond!
Glass is an interesting and amazing material that is essential in many aspects of life.
By tradition, we invite you to watch an exciting video on how glass is made.
Daily using glass objects, almost no one thinks about what this material is obtained from. How are sometimes amazingly beautiful interior items made? How is glass made? Why sunlight freely penetrates through the window into the room? How certain types of glass do not break even with strong impacts?
Production technology
The main material for the manufacture of glass is quartz sand. Yes, the one with which they are strewn sandy beaches and on which in the summer you can walk barefoot with pleasure.
Glass production begins with the fact that the amount of the smallest quartz accurately measured on electronic scales is heated to a temperature of over 1500 degrees C. The grains of sand melt, forming a homogeneous mass. Soda ash and limestone are added to them in small quantities. For what purpose?
soda ash in this process it is a kind of catalyst and causes the sand to melt at a lower temperature, approximately 850 degrees C. This reduces the energy costs of production. But soda is not used without limestone. This fact is explained simply: molten sand and soda ash, when solidified, form a substance that is easily soluble in water (not best material for the production of household items). Magnesium oxide, aluminum oxide, and boric acid. As well as a number of substances that prevent the formation of air bubbles in the mass.
After all the components are brought to a certain temperature, a sharp cooling follows - this will prevent the grains of sand from returning to their original form.
glass rainbow
Crushed quartz (sand) in its natural form contains a small admixture of iron, which gives finished products in future easy green tint. In order to make the material transparent, selenium is added to it. This substance gives off reddish tones, but when mixed with iron, the glass surface turns colorless. And what is glass of various shades made of, and sometimes not even monophonic, shimmering with all the colors of the rainbow?
To give the material color, metal oxides are added to the heated mixture. Cobalt will give saturated blue paint. The product will sparkle with purple hues if manganese is added during the manufacturing process, and green will be obtained from a mixture of chromium and iron. For solar yellow color fit chromium oxide, for emerald green - oxides of chromium and copper. Which components are added depends on the purpose of the glass plant.
The secret of strength
The next process after staining is the crystallization of the mixture. It is otherwise called the homogenizing process. As a result, all air bubbles, veins and other inconsistencies that may further affect the quality of products.
After homogenization, the future glass is delivered to a tank with molten tin at a temperature of about 1000 degrees C. Since tin has a higher density, the liquid glass mass is on its surface. Where it becomes perfectly smooth, it cools a little, acquiring hardness. At the next stage, the mass, which has cooled in the tank to 600 degrees C, is transferred to a roller conveyor. Here, based on the rules of how glass is made with high level quality, it is until the temperature drops to 250 degrees C. The duration of the process is explained by the need for uniform gradual cooling, in order to avoid premature cracks.
Unique waste-free production
A quality control device is installed at the end of the conveyor finished material, and at the slightest flaw, the glass is sent for remelting with a new prepared mixture. After passing the quality control, finished sheets of the desired format are cut and sent either to the warehouse or for further processing. It all depends on the purpose of the product.
The residues after cutting are again put into the mixture for remelting. All rejected material is also launched there. Based on how glass is made, it is safe to say that this production is waste-free.
Kinds
Due to their chemical and physical properties glass is divided according to several criteria:
- by purpose (domestic needs, industrial use, construction);
- by type of processing (chemical, mechanical and special technologies);
- according to the surface texture (matte, glossy, coated with various metals, with and without a film coating).
There is no clear division into categories. When classifying, they proceed from the technology and how glass is made. The end result can be a multi-layer surface with machined edges or a product with a high level of light transmission, cold-cut. It should be noted that a separate quality parameter is the level of light transmission. There is no glass with a 100% level, for domestic use it is 82%. In high-tech products: microscopes, telescopes, various lenses and precision instruments - this figure is over 90%.
