Effect of a novel environmental-friendly chelating depressant DTPMP on the flotation separation of magnesite and dolomite
Yuan Tang, Changming Xu, Qunshan Chen, Qianqian Li, Dongsheng He, Zhili Li, Yue Fu
Abstract
The similar crystalline structures and surface properties of magnesite and its main associated mineral, dolomite, present significant challenges for their effective separation in conventional flotation systems. To achieve selective separation of these two minerals using a sodium oleate (NaOl) collecting system, a novel eco-friendly chelating depressant, diethylene triamine-pentamethylene phosphonic acid (DTPMP), was introduced. This study aimed to investigate the selective inhibitory effects and adsorption mechanisms on mineral surfaces through various experiments and analyses. Under optimal flotation conditions, a concentrate with a MgO grade of 47.02 % and a recovery rate of 86.60 % was obtained from the flotation of mixed minerals. The results indicated that DTPMP selectively inhibits the floatability of magnesite in the NaOl system while having a lesser effect on dolomite flotation. Furthermore, the data analysis included a comprehensive evaluation of the zeta potential , contact angle measurements, and advanced techniques, such as Fourier Transform Infrared (FTIR) spectroscopy, X-ray Photoelectron Spectroscopy (XPS), and computational simulations. These analyses revealed that DTPMP selectively inhibits the flotation of magnesite by competitively adsorbing onto the Mg 2+ sites on the magnesite surface, thereby preventing NaOl from adsorbing and enhancing the separation from dolomite. Consequently, efficient separation of magnesite and dolomite can be achieved through froth flotation.