Rotary kiln installation forms a very complex system, as it consists of various components which affect cement production. However, some problems with particle settling are encountered during operation of tertiary air installation. This paper reports on the results of a study into gas-particle flow in a tertiary air duct installation. This flow was calculated using Euler method for air motion and Lagrange method for particle motion. The results in this paper demonstrate that study focus on the tertiary air installation is a practical measure without the analysis of other processes in the rotary kiln. A solution to this problem offers several alternatives of modifying the inlet to the tertiary air duct. As a result of numerical calculations, we demonstrate the influence of geometry of a rotary kiln modification on the number of large particles transported in the tertiary air duct. The results indicate that in order to reduce large particles, rotary kiln head geometry needs to be modified, and a particle settler should be installed at its outlet.

In the dumps of metallurgical enterprises of Kazakhstan about 700 million tons of waste products are generated annually, and are polluting the atmosphere and the soil. The concentration of valuable components in waste products are no lower than in natural resources. The reserves of coal in the Ekibastuz basin are estimated to be more than a billion tons, and almost half of this is made up of ash. Every year, up to 30 million tons of ash-cinder waste is generated, which presents a serious threat to nature. Gallium and germanium concentrations in dumps are approximately 200 grams per ton, which is comparable to the content in coal before processing. The current research aims at creating a unit to obtain hydrogen-enriched water gas from Ekibastuz coal, with the production of zinc, gallium and germanium sublimates, copper-containing cast iron, slag wool and cast stone, through the joint processing of zinc-rich slag and ash-cinder wastes from thermal power plants. To achieve this, we used previous methods of extreme energy saving and a new method, the smelt layer with inversion phase. Experimental results from the “reactor inversion phase – rotary kiln” (RIPh) unit, which processed zinc-germanium contained slag, showed the potential to extract germanium from zinc sublimates, to reduce iron to the form of cupreous cast iron, and to obtain combustible gases and smelt suitable for slag-wool production. Calculations performed on the joint processing of Ekibastuz coal and zinc-rich slag using the proposed unit “reactor of inversion phase – rotary kiln – gas generator” showed it can obtain hydrogen-enriched water gas, along with the extraction of valuable components of primary raw material.