Effect of N-carboxybutyl chitosan on the flotation separation of apatite from dolomite

With high-grade apatite resources exhausted and economic development, enhancing the apatite quality from calcium gangue such as dolomite has a great significance for production. However, it is difficult to separate apatite from dolomite effectively due to the similar surface properties. In this study, the N-carboxybutyl chitosan ($CBC$) was tested as a potential selective depressant to separate apatite from dolomite in the sodium oleate ($NaOL$). Flotation results of single mineral and artificially mixed mineral confirmed the selective depression effect of CBC. The depression mechanism of $CBC$ was investigated using wettability analysis, Fourier Transform Infrared ($FTIR$), and X-ray Photoelectron Spectroscopy ($XPS$) analyses. The results indicated that the $CBC$ adsorption quantity and intensity on the dolomite surface more than that on the apatite surface, which was due to $CBC$ absorbed on apatite surface by hydrogen bonding, while absorbed on dolomite surface mainly through chemical chelating between $Ca$ on the mineral surface and -COO- on the depressant. These adsorption differences led to the flotation separation of the two minerals.