64｜Glass manufacturing methods, forming methods, and processing methods 2

Hello everyone 🎵

Last week, I enjoyed Otaru, Yoichi, and the Shakotan Peninsula in Hokkaido. This is a special time of year when you can eat both Bafun sea urchin and Murasaki sea urchin. For the past 4 years or so, I've been enjoying sea urchin galore during this season every year. Since it's so fresh, it's eaten with saltwater treatment instead of alum. Once you eat this sea urchin, you won't be able to eat regular sea urchin anymore (lol). I also enjoyed a year's worth of sea urchin 🎵

Now, I started explaining the glass processing method last week. Glass itself is a liquid. We melt the raw materials, turn them into a glassy (liquid) state, and then form the shape of the glass from a state similar to starch syrup.

Let's start by talking about the raw materials. Depending on the type of raw material, glass can be classified into soda-lime glass, crystal glass, borosilicate glass, and so on.

Most glass is made from soda-lime glass. The basic raw materials for soda-lime glass are: ① silica sand, ② soda ash, and ③ limestone. These three are mixed with materials to add strength and color, then melted at high temperatures to create glass. You may not have heard of any of them much, but they are all "minerals" extracted from stones and sand, and surprisingly familiar.

Silica sand is sand made by crushing "quartz." It is a substance called silicon dioxide (Sio2), also known as silica, and is the main component of glass. It is found in the sand of parks and beaches. If you look closely at the sand grains, the transparent, glittering ones are silica sand. When making glass, quartz and other materials are finely crushed and used. Currently, it is also produced by industrial manufacturing methods. When quartz crystals grow large, they form hexagonal columns, which are rock crystal. Rock crystal can also be ground down to be a raw material for glass.

Soda ash, as its name suggests, originally used ash from burning plants, but now anhydrous sodium carbonate (sodium oxide) made from salt is used. It acts to make silica sand easier to melt. Soda ash is not only used in the manufacturing of glass, but also as an ingredient in soaps, detergents, bath additives, and "kansui" which softens Chinese noodles.

Limestone plays a role in making glass solidify more easily. It is a mineral also used in chalk for writing on blackboards, mainly containing calcium oxide, and is extracted from limestone rock. Limestone is distributed throughout Japan, and mined at over 200 locations. Akiyoshidai in Yamaguchi Prefecture and Geibikei in Iwate Prefecture are famous for their limestone formations.

Why is glass transparent? // The main raw material for glass, silica sand, is a highly transparent mineral that does not absorb light. Furthermore, when glass materials melt at high temperatures, the boundaries between particles disappear. Then, when the molten glass cools, the molecules simply cluster together and solidify without arranging themselves regularly. As a result, light entering passes through without scattering, making the glass appear transparent.