INTRODUCTION ■ Objectives ● Brightness ○c| earliness O Purification-dissolving grade a Historical background ■ Major concerns ◇ Costs◇ Environmental◇ Energy South China University of TechnologySouth China University of Technology INTRODUCTION Objectives ●Brightness ●Cleanliness ●Purification-dissolving grade Historical background Major concerns ◇Costs ◇Environmental ◇Energy