Ultrasonically assisted extraction of calcium and ash from char

This study characterized and removed calcium and ash content from char to improve the chemical quality of char as reductant for titanium smelting application. Calcium in char can be classified in two parts: mineral matter and cationic metals associated with organic matrix. Virgin and chemically treated char was characterized by using ISO 1171, wet chemistry methods, ISO 19579, XRF, and B.E.T. methods. In this present work, demineralization of char with mild chemical leachants such as acetic acid, citric acid, gluconic acid and Ethylene Diamine Tetra Acetic acid with three different ultrasonic power input (150 W, 270 W and 300 W) and semi-dual frequency of 40 kHz tank was investigated. Actual power dissipated into the system was calculated from the calorimetric measurement. An optimum set of process parameters are identified and validated. The ultrasound technology was compared with soaking technology to determine the efficiency of ultrasound system for the removal of calcium. The removal of calcium was exponentially higher with ultrasonic treatment than without it. Results revealed that mild chemical reagents do not harm the carbon content of char. It is evident from the results that amongst the leachants used; acetic and citric acid has caused significant removal of mineral phases. (paper)