Take a look around you. Chances are, if you’re in any indoor premises, there will be at least something made from glass. Even if you’re outdoors, the smartphone’s screen in your pocket is made from glass.
That is how common glass is.
Being so versatile, it is incredibly reliable as well. This brings us to an essential question, how glass is made from sand?
After all, a substance/material so versatile would also have a precise manufacturing process. That is what I will highlight today.
A Brief History of Glass Making Process
Glass has been around since 2600 BC. The oldest record of making glass is of the Egyptians. Civilizations like the Mesopotamian or Egyptian civilizations used glass for various purposes. During excavation, glass was also found in China, dating back to the same.
In ancient times, the most common form of glass was beads. It was used in jewelry and was widely regarded as an accidental invention. During the Bronze Age, glass production drastically reduced as it was considered a luxury.
Later on, excavations in England revealed that glass was also used in the 10th century in cathedrals and palaces. In the nineteenth century, glass production increased significantly because of its use in glass windows, doors, etc. Since then, glass has been in mass production in different forms and types.
In a nutshell, glass has been around since 2600 BC in one form or the other.
How Glass Is Made from Sand?
While the manufacturing process of glass varies depending on the type of glass and economy of scale, today, I will cover the float manufacturing process of glass.
Step 1: Melting
The first step involves creating a mixture of silica sand and other raw materials; the composition can vary depending on the type of glass and its exact application. One constant thing is that the ingredients should be fine-grained. After that, the melting of this mixture takes place in a furnace at 1500°C.
In the same furnace, the refining process also occurs in which gas bubbles are removed by moving the glass through a narrow canal.
These processes cumulatively take about 50 hours before the high-quality output is produced.
Step 2: Tin Bath
At the output is a spout that pours the liquid into a flat mirror-like surface. The surface is in a shallow pool filled with molten tin; the temperature of molten tin is 1000°C. You get a flat ribbon of glass on the surface. Since the glass is viscous, it does not react or fuse with the liquid tin.
The speed at which it spreads on the smooth surface helps the manufacturers control the thickness of the glass. After that, rollers are used to flatten the sheet of glass further.
At the output, the glass ribbon is at a temperature of 600°C.
Step 3: Use the Annealing Chamber
After that, the ribbon enters what is known as the annealing chamber. The job of this chamber is to eliminate the stress in the glass ribbon by exposing it to a tunnel for heat treatment. This tunnel gradually lowers the glass temperature to 250°C from 600°C.
Step 4: Inspect the Quality
This is where the quality inspection of the glass takes place. If the steps mentioned above are done precisely, there is hardly ever any problem with glass at this stage. Usually speaking, automated scanners are used to detect any problems.
Step 5: Cut It into Size
The glass ribbon moves on the conveyor rolls since the bulk of the manufacturing process, including the inspection process, is completed. It is exposed to diamond wheels which cut the glass ribbon into appropriate size.
Step 6: Coat the Glass
This step is optional. In case thermal coating is needed, it is applied during this step. Some other coating might be applied according to the application.
Is It Possible to Make Glass at home?
Yes, it is possible to make glass at home, but you will need a furnace and a kiln.
Step 1: Get Silica
The first step is to procure silica sand, the primary ingredient for making glass. If you do not get pure silica sand, you might add very little manganese dioxide to counter the impurities. Apart from that, you have to also procure a face mask, gloves, and so on.
Step 2: Create a Mixture by Adding Sodium Bicarbonate and Calcium Oxide
Washing soda or sodium bicarbonate is another ingredient that you will need. It reduces the temperature at which you can melt glass. It creates a condition that lets the water pass through glass. To avoid this, you need to add calcium oxide to the mixture. These cumulatively should make up to 30% of the entire mix.
Step 3: Add the Other Chemicals
According to the application, you might need to add other chemicals. For example, aluminum alloy makes it more durable. Lead oxide (max 25%) makes it sparkle. However, extreme precautions should be taken. Eyeglass lenses, and other protective gear, should be worn when handling and adding these chemicals.
Step 4: Add Color Chemicals
Compounds like copper and iron oxide can provide a greenish shade to the glass. Similarly, sulfur produces a yellowish tint. Depending on the color of the glass you want, you need to add these chemicals.
Step 5: Put the Mixture into a Crucible
To make this mixture, you will need to add it to a heat-resistant crucible. Only when it can withstand temperatures of up to 3000°C will the crucible be useful enough. You have to fasten the crucible inside the funnel when it is off. Ensure that you are attaching other arresting mechanisms before turning on the furnace.
Generally speaking, you have to take the furnace up to a temperature of 2500°C.
Step 6: Melt the Mixture
Once the furnace reaches 2300°C, the mixture will start melting. However, if you have added washing soda to it, it will start melting at 1500°C.
Step 7: Stir the Mixture Carefully
To remove the gas bubbles from the mixture, you will have to stir it. However, before you do so, you need to wear all the protective gear, and even then, you have to do so under the supervision of a professional.
You might also have to add chemicals like sodium sulfate or sodium chloride during this process. It is to get the desired properties of glass.
Step 8: Give the Desired Shape to Glass
After that, you have to shape the glass. To do so, you have to first gather the mixture at one end of the hollow tube. A mechanical blowing process gives proper shape to the molten mass of glass.
Another option is to deposit the mixture in a tin bath (explained above) and let the edge rollers shape the glass sheet.
Step 9: Cool the Glass
The last process involved is annealing. It is necessary to ensure that the glass gradually cools and does not become brittle.
During this process, the temperature of the glass reduces gradually.
You would need a kiln that will act as the annealing chamber for glass.
Most Common Uses of Glass
Applications of glass are endless. I will cover the most common applications below:
1. Storage Solution
Tinted glass can easily block light. That is why it can keep the contents in proper condition for a long time. Due to the same, glass is used to make storage options like jars, bottles, etc.
These jars are widely used in the food, beverage, and pharmaceutical industry.
Glass tableware is still considered to be premium. Not only that, with different types of glass available, the options in tableware are also increasing.
3. Housing Accessories
What do house windows, facades, insulation materials have in common?
Most, if not all, are built from glass. This is where the properties of glass come in handy. For example, since it can be transparent and tinted, it is a good option for windows and facades. Thicker glass panes can provide insulation from sound and the weather outside. Due to the same, it is an excellent insulation option.
You will be surprised at the amount of glass used in the construction industry.
Think about computer monitors, smartphones, TV screens, microwave ovens, cooktops, and so on. All of them use glass in one form or the other.
With toughened and tempered glass options available, the sturdiness of glass is increasing more and more. That is why, to give a premium look to the appliances and electronics, more and more manufacturers are using glass.
Not only automobiles but any medium of transport uses glass significantly.
When it comes to cars, SUVs, trucks, windscreens, backlights, etc., are made from glass.
Windowpanes are made from glass whether you’re speaking about aircraft, cars, ships, or any other mode of transport.
6. Medical Equipment
Medical equipment uses glass for a variety of purposes. It can be to create an enclosure door to observe something.
Many instruments consist of a magnifying glass as well. It helps to observe a sample or a specimen more carefully.
Fiber-optic cables have been used in the telecommunication industry for a long time. They provide excellent transmission of signals at higher speeds. These days, fiber optics are being installed right up to the end-user’s home.
You would be surprised to know that fiber-optic cables consist of glass at the core. Through this glass cable, information travels in the form of light.
With the increasing consumption of fiber optics, the use of glass in the telecommunication industry is also increasing.
8. Upcoming Applications
Many innovative applications use glass. For example, smart meters are being developed worldwide to double up as projection screens, larger smartphones, or TV. These use glass as well.
Similarly, digital signage also uses glass to provide information and offer a touchscreen.
Frequently Asked Questions
1. Is glass made up of sand?
Yes, glass consists of sand and many other ingredients like soda ash, limestone, etc. A lot also depends on glass and its application.
2. Is glass solid or liquid?
The properties of glass change according to the state in which it is in. Technically, glass is considered to be an amorphous solid. However, it is very close to a liquid in molten form. When it cools down, it solidifies.
3. Is there metal in glass?
There can be some metallic substances in glass-like iron oxide. However, the glass itself is not a metal.
4. What are the four types of glass?
The four types of glass are:
Different processes can be used to make different types of glass, and accordingly, their name might change a bit.
Next time you see glass around you, you will know how it is made right away. The procedure is so precise and detailed that even if you replicate the procedure, there are high chances that you will be able to make good-quality glass.