A novel coal tar-based collector for effective flotation cleaning of low rank coal. (10th November 2020)

• Record Type: Journal Article
• Authors: Li, Yijiang; Xia, Wencheng; Peng, Yaoli; Xie, Guangyuan
• Is Part Of: Journal of cleaner production. Volume 273(2020)
• Publication Date: 2020-11-10
• Subjects: Coal flotation -- Adhesion -- Collector -- Bubble -- Coal tar; Factory and trade waste -- Management -- Periodicals; Manufactures -- Environmental aspects -- Periodicals; Déchets industriels -- Gestion -- Périodiques; Usines -- Aspect de l'environnement -- Périodiques; 628.5
• DOI: 10.1016/j.jclepro.2020.123172
• Languages: English
• ISSNs: 0959-6526

Abstract

Abstract: Clean utilization of low-rank coal is an important problem in coal production and sustainable development. Flotation of low-rank coal is a major challenge for clean utilization of coal resources and environmental protection in the world. Common oily collectors were not effective for low-rank coal flotation, this paper proposed a novel collector named CTB collector, which is a mixture of diesel and extracted light components from coal tar using diesel as extractant. The Gas chromatography-mass spectrometry and Fourier transform infrared spectroscopy analyses revealed that the CTB collector contained more aromatic compounds and oxygen-bearing functional groups than the diesel. The non-polar sites on coal surface can bind with the aromatic compounds through Van der Waals force and π-π stacking interaction. The polar sites can interact with the oxygen-bearing functional groups through hydrogen bond. The adsorption of macromolecular aromatic compounds on non-polar sites can also cover the polar sites adjacently. The hydrophobicity and floatability of low-rank coal were improved through above adsorption. The flotation results showed that the combustible matter recovery of CTB collector was 21%∼34% higher than that of diesel and the CTB collector can save 1500 g/t dosage than diesel while the flotation performance was still better. The coal flotation efficiency index of the CTB collector was 130–240 higher than that of the diesel. The particle carried index was designed to evaluate the carrying ability of a single bubble to coal particles. The flocs were significantly formed during flotation using the CTB collector. These flocs enhanced the recovery of low-rank coal. The particle carried index of the CTB collector-treated coal particles and bubble was higher than that of diesel-treated coal particles and bubble. The induction time results showed that the CTB collector accelerated the adhesion between coal particles and bubble while slowing down the adhesion between gangue particles and bubble. This study can not only provide new strategies for the design of coal flotation reagents and the evaluation of the adhesion efficiency between particles and bubbles, but also be beneficial to the clean utilization of coal energy and environmental protection. Graphical abstract: Image 1 Highlights: A novel flotation collector was prepared by using coal tar and diesel oil. Novel collector has great effect on the low-rank coal flotation. A calculation method of the particles-bubble adhesion was introduced.