Development of coating pigment from paper sludge ash

A recycle process of the paper sludge ash was developed for the coating-pigment utilization. We found that a calcination process was required to increase the brightness of the paper sludge ash after incineration. The calcination-temperature was investigated to manage the property of the recycled pigment. Especially, pulverization treatment and abrasivity was discussed in order to obtain quality of the recycle pigment. Also the pilot test was carried out in order to confirm the results of laboratory experiments. The required times times of the kiln-calcination were 60 min at 1000C and 100 min at 900C. At the lower temperature (900C) and the pulverization and the abrasion of the recycled pigment were improved effectively to the kaolin clay level (brightness) and GCC level (abrasivity). The influence of the calcination-temperature on fusing was also discussed with the XRD observation in this study.