Scientists have proposed a new affordable method for the production of high-quality binders for the construction industry based on synthetic gypsum made from industrial waste. It solves the problem of garbage and does not use natural resources.
Gypsum binders are used everywhere in construction – we are talking about light, plastic and refractory materials with low sound and thermal conductivity. An important aspect is the hypoallergenicity of such materials, as well as the absence of the risks of developing silicosis when using them.
Gypsum consists mainly of calcium sulfate dihydrate, which is a natural mineral. Scientists have developed a method for creating a synthetic analogue. It is more energy efficient than natural mineral processing.
Usually, gypsum extracted from the earth needs to be ground into powder before it can be used. This process requires a large amount of electricity. In addition, not all countries have extensive gypsum deposits that can be exploited.
In search of a more sustainable alternative, an international consortium of research institutes have instead turned to construction waste as their starting material. In particular, they combined three key ingredients: sulfuric acid left over from the production of heat-resistant fibers, limestone powder obtained as a by-product of limestone processing, and water.
Scientists have mixed and processed these substances – and received a synthetic form of gypsum. It contains at least 95% calcium sulfate dihydrate by weight.
After boiling the ingredients in a traditional gypsum pot, scientists obtained stucco – it is mainly used as a heat-resistant, moisture-retaining, sound-absorbing and fire-retardant material. When the materials were placed in an autoclave, the result was a high strength gypsum. And when the substances were fired and then cooled, a precursor of gypsum was obtained, known as anhydrite – it is used together with gypsum in building materials, as well as a drying agent in plaster, paint and varnish.
An innovative method for the production of durable binders based on synthetic gypsum obtained from waste was proposed by scientists from NUST MISIS, the Institute of General and Inorganic Chemistry of the National Academy of Sciences of Belarus, the Belarusian State Technological University and the University of Limerick (Ireland). The new method will significantly reduce the cost of production.