Chrome-free Refractory Material Used In Rotary Cement Kiln
Magnesia chrome brick used in rotary cement kiln will produce 6+ Cr ion when corroded by high temperature reaction, especially at the kiln outlet, where has high oxygen content. Cr 6+ has a enormous contamination to environment and threat to human health. In the kiln 27~35m away from kiln head, i.e. hot part of transition zone, temperature and alkali content are both high, Cr element in magnesia chrome brick can easily converted into K2CrO4 and volatilized, so magnesia chrome brick can be corroded quickly. Thus, chrome free refractory bricks is a better replacement of magnesia chrome brick, can not only prolong service of kiln lining but also decrease residue brick pollution.
Since 1980s, chrome free alkaline bricks are researched and developed in China, and great progress has be made in research, manufacturing and application.
Chrome free alkaline refractory bricks used in rotary cement kiln include:
- Magnesia calcia (zirconia) series dolomite bricks, Magnesia dolomite bricks, magnesia zirconia dolomite bricks and fused magnesia zirconia bricks.
- Magnesia alumina (zirconia) series periclase-magnesia alumina spinel brick(spinel brick), spinel zirconia brick.
- Magnesia iron alumina series periclase-magnesia iron spinel brick( iron alumina brick).
- Magnesia iron series periclase-magnesia iron spinel brick( magnesia iron brick).
- Other spinel or compounded spinel bricks.
Currently the mainly used chrome-free refractory bricks in China are alumina iron bricks, magnesia iron bricks and magnesia alumina spinel bricks. RS kiln Refractory produced magnesia iron spinel bricks has excellent refractoriness, thermal shock resistance, kiln lining adhesion property and low thermal conductivity. Magnesia iron spinel bricks have been used in many large sale rotary and proved the better performance, max. service life prolonged to almost two years. When magnesia iron spinel bricks are applied in rotary cement kiln, there are two requirement should be met, first, the cement kiln has good lining condition, secondly, kiln lining should be in proper maintenance.
