What causes black and white color of high alumina bricks?

[China Aluminum Network] The main reason why high-alumina bricks appear black and white is due to the high temperature and reducing gas atmosphere, reducing iron and titanium ions, and decolorizing low iron and titanium ions at lower temperatures. In addition, the location of the high-alumina brick in the kiln is too close to the fire box, resulting in high-temperature hot air caused by oxygen-enriched operation, to avoid reducing the atmosphere; in the cooling process, slowly cooling, so that low-cost iron, titanium ions reoxidation and decolorization. Therefore, it is necessary to pay special attention to the refractories manufacturers in the production process. These problems are the reasons that affect the appearance quality of high-alumina firebricks.