Chemical compositions play an important role in the construction industry. The development and improvement of building materials often depends on the integration of chemical components. A key issue here is chromate reduction in cement. Cement remains an indispensable building material for structures and buildings. In this article, I would like to explain the importance of iron sulfates in this process and show how we at COFERMIN are helping to create more reliable and environmentally friendly building products.
Depending on the raw materials and production conditions, hexavalent chromium can occur in cement in concentrations of up to 30 ppm. In this water-soluble form, it can penetrate human skin and trigger allergic reactions such as chromate dermatitis, known as bricklayer’s itch. To minimize these risks, a reduction of the chromate content in cement to less than 2 ppm is required in accordance with EU Directive 2003/53/EC and Regulation (EC) No. 1907/2006.
Iron sulfate has proven to be an efficient means of reducing hexavalent chromium to the more harmless trivalent form. This chemical reaction takes place immediately after the addition of mixing water to the cement. However, iron sulfate can have advantages and disadvantages in different forms and applications.
We supply different grades of iron sulfate, which vary in form, effectiveness, and handling. These differences allow for customized application depending on the specific requirements of cement production.
This thermodynamically stable form has low residual moisture, high thermal stability, and does not tend to clump. It can be used universally, both before and after grinding, and is ideal at high temperatures. However, its slightly poorer water solubility requires a higher dosage.
Highly water-soluble and cost-effective. This iron sulfate is often dosed in the form of moist salt or as a saturated solution. It is ideal for low chromium content of up to 5 ppm, but requires special storage conditions due to residual moisture, which can cause clumping.
Our iron sulfates are produced from by-products of the steel industry and titanium dioxide production. This process produces diluted sulfuric acid, which reacts with iron compounds to form iron sulfate. Our customers benefit from the sustainability and flexibility of our products. Iron sulfate monohydrate and iron sulfate heptahydrate are available in both powder and granulate form and are delivered in 25 kg bags, big bags, or loose in dump trucks.
So, once again: iron sulfate is an important component in the manufacture of cement and other building materials. It contributes to chromate reduction and promotes sustainability and flexibility in the construction industry. We place great importance on tailoring our products to the specific requirements of our customers in order to offer genuine added value.
