Diversity at its Purest: HDK^®

Hydrophilic HDK^® is manufactured by the hydrolysis of volatile chlorosilanes in an oxyhydrogen flame. In the flame, droplet-like primary particles form, some of which fuse together in the colder region of the flame to create large chain-like aggregates. These harden completely in the colder flame region, and in turn become attached to each other to yield agglomerates. Chemically, HDK^® pyrogenic silica is highly pure amorphous silicon dioxide and has the appearance of a loose white powder. Just 18 g would cover an area the size of a soccer pitch! HDK^® is completely non-toxic to humans and the environment.

HDK^® is a key component of the integrated production system – which is one of WACKER’s major strengths. Basically, integrated production involves using the byproducts from one stage as starting materials for making other products. This ensures that the byproducts are used to the fullest extent possible and that raw materials are recycled within a closed loop. Compared with open-ended production processes, integrated production lowers manufacturing costs and conserves both energy and resources. The raw materials are used in a sustainable manner while environmental protection is integrated into production.

HDK^® in the integrated production system:

• in the chlorine-HCl system, the toxic chlorinated intermediate products are converted into nontoxic byproducts, such as hyperpure silicon, silicones or pyrogenic silica. In the integrated material loop, both hydrogen chloride and some of the energy in the form of heating steam are recovered. The production of HDK^® markedly enhances polysilicon production by providing an outlet for byproducts which are used to make HDK^®. This closes the loops there and conserves both energy and resources.
• in the integrated silicon system, over 3,000 silicone products, pyrogenic silica and polysilicon are produced from silicon, methanol and common salt.