New developments in the production of heavy soda-ash via compacting method

Abstract

Sodium carbonate, also called soda, is mainly used in the glass industry, but also has its operative range in the chemical industry, i.e. for processing sodium phosphates, detergents and soaps. It is differentiated between light, calcined soda, which has a bulk weight of approx. 0.5 kg/l, and heavy soda with a bulk weight of 1.0–1.1 kg/l. One of the oldest methods for processing heavy soda from light soda is the monohydrate method, where by addition of water monohydrate is formed, from which subsequently, the crystal water is removed in a steam pipe calcining drum. As this method is very energy- and therefore cost-intensive, for reasons of reducing the operating costs in the last years, it was changed more and more to the method of compacting with subsequent crushing and following screening. However, due to mechanical screening, this method is limited to a minimum particle size of 200 μm. But as the international market demands today a multitude of particle sizes in the range between 75 and 1.180 μm and the particles have to be absolutely dust-free at the same time, a new method has been developed and turned into practice. In two plants of recent dates, with a capacity of 160.000 tons/year, the new demands of the market have been considered. The plant will be explained here in detail.