Last week it was scientists at the Colorado School of Mines making glass using silica produced from food waste.
This week it’s a research team led by University of Michigan engineering professor and ACerS Fellow Richard Laine (in the screen capture above; credit: U of M/YouTube) unveiling an inexpensive process to transform common silica from sand and other materials into chemicals that can be used in fireproofing and waterproofing materials, textiles, and other products.
The distillation process developed at UM depolymerizes silica from sand, producing low-cost silica-containing chemicals that could replace or complement carbon-containing materials, according to the video.
Laine says in an email that his team is experimenting with a wide number of diols, including ethylene glycol and others. But “there is only one type of silica compound that distills. It falls in the general class called a spirosiloxane. It is a special class of alkoxysilanes like [tetraethyl orthosilicate] TEOS and [tetramethyl orthosilicate] TMOS…but can [come] from directly from silica sources.”
The video depicts results of a wood treatment made with the distilled silica compound that imparts significant fire resistance. “We soak the wood in the dissolved silica product and then expose it to a mild acid treatment to release the silica,” Laine explains via email. “Other people have done this, but not from something you can distill from any silica source.”
In the video, Laine explains that forms of silica with high surface area—diatomaceous earth and rice hull ash, for example—work best for the process. In the case of rice hull ash, “You are taking something that is a waste product and recycling it into a vaulable commercial product,” he says.
As Laine points out in the video, silica makes up about 25% of the mineral content of the Earth’s surface. “So, if you could develop commercial routes that use silica, or sand, then there’s a great cost savings,” he says, adding that the process also recycles waste products, simplifies production, saves energy, and removes toxins from the environment.