Optimization of the performance of basic refractory bricks for cement rotary kilns

Source/Quelle: Magnesita

1 Examples of LSF and SR in two different plants. The area between the straight lines defines the region of optimum coating formation

Source/Quelle: Magnesita

2 Microscopic observation of the coating (bottom) formation onto a doloma brick (top). The square at the top left depicts the interface, and shows a dense coherent reaction layer

Source/Quelle: Magnesita

3 Microstructure of 98 %+ DBM produced from carbonate (left), in comparison to a commercial 98 %+ DBM produced from brines (right). Structure of the carbonate-derived DBM is coarser, leading to larger crystals and pores

Source/Quelle: Magnesita

4 Microstructure of a magnesia-spinel brick (lower right) corroded by cement clinker (upper left). The periclase crystals resist infiltration and wear, which is limited to their surface. Pores (darker areas) are protected by the crystals, and not infiltrated, due to their closed nature

Source/Quelle: Magnesita

5 Deposition of salts inside a magnesia-spinel brick

Source/Quelle: Magnesita

6 Loss of modulus of elasticity after repeated cycles at 1500 °C for selected magnesia-spinel bricks

Source/Quelle: Magnesita

Magnesite mine, Brumado/Brazil

Source/Quelle: Magnesita

Refractory performance in the rotary cement kiln is dependent on a combination of mechanisms. Information about the process, as well as improved refractory technologies must be considered in order to extend the service life.

1 Introduction

The global cement industry faces a turning point, and the degree of success in adapting to the changing times will determine its future. Among the challenges for the industry, one can list:

Reduction of energy costs

Replacement of fossil fuels by waste-derived fuels (WDF)

Increase of the share of recycled materials in the composition of the raw meal

Reduction of emission of greenhouse gases

Development of new technologies and practices to ensure a self-sustainable business, with zero environmental and social liabilities

Notwithstanding the fact of being the main source of potential...