Woodwork protection against fire
Impregnation of wood with a potassium silicate solution is an easy and low cost way for rendering the woodwork of houses secure against catching fire. The woodwork is first saturated with a diluted and nearly neutral solution of potash silicate. After drying, one or two coats of a more concentrated solution are usually applied.
In industry, the various grades of sodium silicate are characterized by their SiO2:Na2O ratio, which can vary between 2:1 and 3.75:1. Grades with this ratio below 2.85:1 are termed ‘alkaline’. Those with a higher SiO2:Na2O ratio are described as ‘neutral
User-friendly geopolymer cements
Although geopolymerization does not rely on toxic organic solvents but only on water, it needs chemical ingredients that may be dangerous and therefore requires some safety procedures. Material Safety rules classify the alkaline products in two categories:
The two classes are recognizable through their respective logos displayed below.
user hostile and user friendly comparison
When we started the research on geopolymer cements, we decided to select alkaline conditions that are User-friendly. (Na,K,Ca)-Poly(sialate-siloxo) and K-Poly(sialate) products (resins, binders and cements) have starting molar ratio SiO2:M2O ranging from 1.45 to 1.85. Unfortunately, this is not followed by other scientists and technicians involved in the development of so-called alkali-activated-cements, especially those based on fly ashes, with molar ratio in average below 1.0. Looking only at low-costs consideration, not at safety and User-friendly issues, they propose systems based on pure NaOH (8M or 12M). For example in a “State of the Art” on alkali-activated fly-ash cements, wrongly named geopolymer technology, published in 2007, several scientists claimed that the pure NaOH system should be considered as the reference for fly-ash-based cements (see: Duxson P., Fernandez-Jimenez A., Provis J.L., Lukey G.C., Palomo A. and van Deventer J.S.J., Geopolymer technology: the current state of the art, J. Mater. Sci., 42, 2917-2933, 2007). These are User-hostile conditions for the ordinary labor force employed in the field.
Finally, companies refuse to support the liability and pay high insurance fees based on such out-of-date processes. Indeed, laws, regulations, and state directives push to enforce for more health protections and security protocols for workers’ safety. Further details on fly-ash-based geopolymer cement in the page GEOASH, a project aimed to develop a real industrial process driven by these constraints.