Coadsorption Phenomena in the Separation of Pyrite from Coal by Reserve Flotation

Depressing effect of flocculants on molybdenite flotation

“…As these measurements demonstrate, the effect of dextrin is quite visible even at 1 mg of dextrin/L (similar effect of dextrin on coal wettability was shown by Miller et al (1984). Since the basic structural unit of dextrin and starch, a-D-glucose (Fig.…”

A molecular dynamics simulation study of water structure and adsorption states at talc surfaces

“…Thus, the only possible explanation is the hydrophobic interaction between the substrate and the dextrin molecule (Haung et al, 1978;Smith and Dang, 1994b;Wie and Fuerstenau, 1974). Previous studies have demonstrated the importance of hydrophobic bonding of dextrin at naturally hydrophobic surfaces, as well as oxidized coal surfaces (Haung et al, 1978;Miller et al, 1983Miller et al, , 1984Wie and Fuerstenau, 1974). More recently, it has been found that the same adsorption isotherm describes dextrin adsorption by elemental sulfur (Wisniewska, 2005).…”

An overview of reverse flotation process for coal

“…The work was demonstrated not only at the laboratory level but also at the pilot plant scale (Miller, 1973). In another study by Miller et al (1984) using a well-defined dextrin sample with potassium amyl xanthate and methyl isobutyl carbinol (MIBC), it was found that dextrin adsorbed on both coal and pyrite but the flotation response of pyrite to xanthate was not affected at all. Another study on different U.S. coals showed that pyritic sulphur can be brought down to 1.22% from its initial value of 2.4% with a combination of Z-6 (potassium amyl xanthate) as collector and Amaizo 1706 (canary dextrin) as depressant, representing the most suitable reagents with a second stage clean coal recovery of 79% (Lin, 1982).…”

“…In this regard, the depressants play a critical role by rendering the coal hydrophilic in nature and thus enhancing the selectivity of the process. Except Eveson (1961) who used potassium permanganate, potassium dibromate, persulphates and hypochlorites, the more commonly used coal depressants are either the organic colloids such as dextrin and starch or humic acid (Miller, 1975;Miller et al, 1984;Lin, 1982;Ding and Laskowski, 2006a,b;Melo, 2005;Zhang et al, 2013;Pawlik and Laskowski, 2003a,b;Pawlik, 2002;Patil and Laskowski, 2008). The depressing action of quaternary amines was also investigated by Stonestreet and Franzidis (1988) which did not give encouraging results and so they used dextrin in their later works (Stonestreet and Franzidis, 1992).…”

“…the mineral matter was floated and reported in the froth phase while the clean coal was depressed and remained in the suspension. The concept was further developed for the selective removal of pyritic sulphur from US coals by several investigators (Baker et al, 1973;Miller, 1973Miller, , 1975Miller and Deurbrouck, 1982;Lin, 1982;Miller et al, 1984). Consequently the study of reverse flotation of coal with a motive to lower the ash content of coal was carried out by many scientists and researchers (Stonestreet and Franzidis, 1988, 1992Vamvuka and Agridiotis, 2001;Pawlik and Laskowski, 2003a,b;Melo, 2005;Ding and Laskowski, 2006a,b;Patil andLaskowski, 2008, Zhang et al, 2013;Ozturk and Temel, 2013;.…”