Production of high value-added filler from harmful dust of marble industry using N-sodium lauroyl sarcosinate surfactant as a new flotation collector

Abstract

In the stone industry, about 73% of the total production is generated as solid waste. In the processing phase, only 20% is produced as harmful ultra-fine sawdust sludge. In the Turah area, Cairo, Egypt, an estimated 448,000 tons are produced annually. About 60% of the total production of dimension stones is carbonate stones. The objective of this study is to properly dispose of the ultrafine pollutants and produce value-added products. The ultrafine marble waste was characterized by different methods such as XRD, XRF, FTIR, particle size analysis and zeta potential. Calcite and dolomite minerals were the main constituents of this waste (91%). The average particle size was 6.656 µm. The fine fraction with a particle size of less than 25 µm contains 97.6% calcite with 81% weight. Sodium N-lauroyl sarcosinate (SNLS) was used as a selective flotation collector for calcite as a calcium mineral. A flotation concentrate with a purity of 99.6% and an overall yield of 80% was obtained at a pH of 9. The bleached product meets ASTM standard specifications for paint and paper applications.