What's The Difference Between Ordinary Glass,High Borosilicate and Lead Glass?
What is the difference between ordinary glass, high borosilicate glass and lead glass? How can we distinguish them in our daily life?
These three glasses are different in chemical and physical properties. We can judge these three different glasses based on their properties:
1.The Chemical composition of ordinary glass, high borosilicate glass and lead glass:
(1)Ordinary glass:
The raw materials of ordinary glass are generally sand, sodium carbonate, calcium carbonate, etc. the mixture of sodium sulfate and carbon can also be used to replace sodium carbonate. The main chemical components are silicon dioxide and other oxides. Colored glass can be made by mixing some metal oxides or salts.
(2)High borosilicate glass:
On the basis of ordinary glass, high borosilicate glass is added with 12.5~13.5% boron. In the manufacturing process, glaze sodium silicate sand, soda water and lime are also added. Its strain temperature can reach 520 ℃, and the strength is higher. And lower thermal expansion coefficient: (3.3 ± 0.1) × 10-6/k, only about 1/3 of ordinary glass, so it is also called 3.3 boro.
(3)Lead glass:
Lead glass is added with lead oxide on the basis of ordinary glass. Compared with ordinary glass, lead glass has low hardness and is easy to cut. It can be made into various handicrafts and can be used in the medical field to prevent X-rays. It is also called medical X-ray radiation proof lead glass plate.
Crystal glass is a handicraft made of silicon and lead oxide. It is very shiny and has high clarity, which is similar to natural crystal. If it contains more than 24% lead, it is called full lead crystal. If it is less than 24%, it will be reduced to lead crystal. The lead glass is made with more texture and permeability. Because people are more and more concerned about environmental protection, the production of crystal glass is also permeated with environmental protection elements, advocating lead-free and barium free.
2.Hardness of the three glasses:
The hardness of high borosilicate glass is the highest, the ordinary glass is the second, and the lead glass is the lowest.
In daily life, high borosilicate glass is used as raw material in almost all glassware in the laboratory because of its high hardness and low expansion coefficient. Ordinary glass plays a complementary role in laboratory glassware due to its low processing cost. Lead glass is widely made into various decorations and handicrafts because it is easy to carve.
3.Safety of the ordinary glass, high borosilicate glass and lead glass:
Both high borosilicate glass and ordinary glass have very stable chemical properties at low and high temperatures, and no harmful substances will be precipitated, so they can be used safely.
Generally speaking, high borosilicate glass is more heat-resistant, and can withstand an instantaneous temperature difference of up to 150 ℃, while ordinary glass can only withstand 75 ℃. The water just boiled is 100 ℃. If you are not in an extremely cold area, you can't crack it with a temperature difference of 150 ℃. But ordinary glass won't work. It will crack when poured into boiling water after catching a cold.
Lead glass can resist radiation very well, but it will release some lead at high temperature, which is harmful to human body. So many exquisitely carved handicraft cups are not suitable for eating.
4.Appearance of the ordinary glass, high borosilicate glass and lead glass:
High borosilicate glass can be thinner and lighter because of its high strength. At the same time, compared with ordinary glass, high borosilicate glass has higher light transmittance, more crystal clear and better use experience.
Lead glass also has very good light transmittance, and the handicrafts made of it are very beautiful. We should try to avoid using it as a container for food, especially hot water.
How can we distinguish ordinary glass, high borosilicate glass and lead glass in our daily life?
The following three methods can be used:
1.We can judge from weight:
High borosilicate glass products are usually thinner and harder. The ordinary glass is the second. Lead glass is usually heavier.
2.We can judge from sound of knocking:
Generally speaking, the knocking sound of high borosilicate glass is very clear, that of lead glass is very dull, and that of ordinary glass is between the two.
3.We can judge from the manufacturing process:
Due to the hardness of high borosilicate glass and ordinary glass, it is generally impossible to have a very exquisite carving process, so lead glass products will have a more exquisite appearance carving pattern. But not recommended for food use.
It is very simple to distinguish high borosilicate glass from ordinary glass, which can be identified by temperature difference.