What Is Silica Gel and How to Judge Them?

Silica, also known as silicon dioxide with the chemical formula SiO2, is one of the most complex and most abundant families of materials. And silica gel is an amorphous and porous form of silicon dioxide and produced synthetically into granules that are hard.

The Development of Silica Gel

Most people may think silica gel is a kind of emerging industrial material that lacks perfect processing technology, so they always question whether it is safe and the large-scale manufacturing of silica gel products is allowed or not. In fact, according to a variety of researches we’ve conducted, silica gel is not the product of the development of the modern industry; actually, it has already rooted in the long history of humankind.

In the 11th century, people in South America began to make silicone rubber balls for games and sacrifices – this is the earliest application of silicone we’ve known so far. In 1493, when the Italian explorer and navigator Christopher Columbus set foot on American soil again, he saw that Indians were playing with a black ball that could bounce high after hitting the floor – this ball was exactly made of latex obtained from some kinds of trees.

In the 18th century, the enthusiasm for South America swept across France. In 1736, the French explorer and geographer Charles Marie de La Condamine joined an expedition to South America. He arrived at Quito, Ecuador finally and become the first European to encounter rubber in the process. Later, he presented a paper that described many of the properties of rubber he’d studied.

As for silica gel, it was in existence as early as the 1640s as a scientific curiosity. It was used in World War I for the adsorption of vapors and gases in gas mask canisters. The synthetic route for producing silica gel was patented in 1918 by Walter A. Patrick, a chemistry professor at Johns Hopkins University.

In World War II, silica gel was indispensable in the war effort for keeping penicillin dry, protecting military equipment from moisture damage, as a fluid cracking catalyst for the production of high octane gasoline, making carbon disulfide, and as catalyst support for the manufacture of butadiene from ethanol.

Now, the silica gel industry is developing rapidly in China as well. The studies show that the amount of this material we use every year has already exceeded thousands of tons.

How to Judge Whether the Silica Gel Is Good or Not?

At the very beginning, silica gel is only used in the aviation and military fields. Now, it is widely used in electronics, textiles, automobiles, machinery, leather and paper, metal, paint, medicine and medical equipment, electrical appliances, toys, hardware, sporting goods, audio, lighting, and many other industries. Silica gel products are closely associated with our daily lives and work at present.

Now that silica gel is so important, what methods can we use to judge whether the silica gel is good or not, or in other words, how can we tell the quality of silica gel?

You can easily judge them from their appearance sometimes. Silica gel is a kind of non-toxic, odorless, and colorless material with good texture, so it will do little serious harm to the human body. However, these fake or low-quality silica gel products are usually manufactured in a tough and slipshod way – they are toxic and have an awful smell.

Generally speaking, silica gel has excellent tenacity and elasticity, which means that it is resistant to breaking, bending, cutting, or other forms of deformation. So the low-quality silica gel is more likely to deform, while the high-quality silica gel can return to its original shape or size easily. What’s more, the high-quality silica gel usually feels much smoother to touch, for there is a grease-like substance on the surface layer if it is not specially processed before.

You can also tell the quality of silica gel from the colors of the flame. Black smoke will be emitted while low-quality silica gel products are burnt, and there will be black powder left. However, no matter what color the product is, as long as it is made of high-quality silica gel, it will produce white smoke when burnt, and the residue that remains is a white powder.