Convential processes for the expansion of volcanic glasses often lead to a bursting of particles, which results in surfaces with open cells. Approaches to produce closed cell particles mainly focus on the production of very fine spherically expanded particles. The company Binder+Co AG, situated in Gleisdorf and specialised on mineral processing and packaging, decided to extend their product range and bring a new technology for the closed cell expansion of mineral products to the market. The Chair of Mineral Processing acts as research partner, the experimental orientated investigations are conducted in the context of the doctoral thesis of the author. First of all, beside classic mineral processing investigations, a characterisation of raw materials and analyses concerning expansion behaviour, including thermal gravimetric analyses and hot stage microscopy analyses, were accomplished. Based on these investigations the development of a new expansion process, which enables the control of the expansion and the production of different closed cell qualities, is described in detail. Integrating an upstream process step for the preparation of the raw sand guarantees a tight grain size distribution, which is essential for high product qualities, and the decrease of impurities of applied raw materials. Systematic test runs at the pilot plant, which was put into operation at Binder+Co AG in Gleisdorf, describe the consequences of plant parameter variation and build the basis for further production operation, which are best adapted for particular product requirements. For differentiation between such a produced novel product and conventional products, a new method for estimating the degree of closed surface was established. Finally, possible product applications and resulting properties are discussed.