Effect of microemulsified collector on froth flotation of coal by
Effect of microemulsified collector on froth flotation of coal by
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发表时间：
2013
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通讯作者：
L. Li;X. Lu;J. Qiu;D. Liu
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作者：
L. Li;X. Lu;J. Qiu;D. Liu
采矿方法和清洁工艺的现代化增加了所产生的原煤细粒的数量（Cebeci，2002; Kim等人，1991; Pawlak等人，1985年）。煤炭制备或清洁是从原煤中去除不可燃矿物（Capes和Germain，1982; Erol等人，2003; Mehrotra等人，1983年）。常规的煤净化技术对于细粒煤加工是低效的（Kim等人，1991年; Mehrotra等人，1983年）。泡沫浮选是基于不同组分的表面疏水性差异的细颗粒分离过程。它通常对煤炭清洁非常有效，因为煤炭是天然疏水的，而矿物质通常是亲水的。由于煤的疏水性，泡沫浮选大多采用煤油、原油、燃料油等非极性捕收剂。和某些煤焦油馏出物（Wójcik等人，1990; Solov'伊娃和Muklakova，1995; Petukhov，1995）。捕收剂分散成纸浆中的液滴，并且这些液滴与煤颗粒碰撞、粘附并涂覆煤颗粒，从而增加它们的疏水性（Polat等人，2003年）。分散这些非极性油通常是困难的，并且油滴的尺寸通常很大。这导致捕收剂消耗高和浮选性能差。因此，研究降低捕收剂用量和成本的方法是有意义的。非极性油可以通过乳化分散成较小的液滴（Duong等人，2000; El-Shall等人，2000; Laskowski，1992; Laskowski和Wang，1997; Song等人，1999年）。乳液是其中一相的小液滴分散在另一相中的混合物。它们在化学上不稳定，因此乳化捕收剂也不稳定，并且在储存期间可能发生破乳。捕收剂的破乳显著降低了其分离效率。已经报道了具有复杂结构和高能耗的特殊乳化装置来混合和制备不稳定的乳化捕收剂;然而，其在煤泡沫浮选工业中的应用是不切实际的（Jones等人，1978年）。微乳液是透明的，并且是热稳定的。与乳液类似，它们由表面活性剂（或表面活性剂和助表面活性剂）、油和水组成。助表面活性剂通常是具有两个（乙醇）至四个（丁醇）C原子的短链醇。微乳液的平均液滴尺寸为5-100纳米，而乳液的平均液滴尺寸为数百微米（Huibers，1996）。微乳液在动力学和化学上是稳定的，因此可以自发形成（Vollmer和Vollmer，2001）。油可以通过微乳化分散成更小的液滴。微乳液的自发形成降低了与制备相关的难度和能量消耗。微乳化捕收剂对煤泡沫浮选的影响
The modernization of mining methods and cleaning processes has increased the quantity of raw fine coal particles produced (Cebeci, 2002; Kim et al., 1991; Pawlak et al., 1985). Coal preparation or cleaning is the removal of non-combustible minerals from run-of-mine coal (Capes and Germain, 1982; Erol et al., 2003; Mehrotra et al., 1983). Conventional coal beneficiation techniques are inefficient for fine coal processing (Kim et al., 1991; Mehrotra et al., 1983). Froth flotation is a fine particle separation process, based on the difference in surface hydrophobicity of different components. It is often very effective for coal cleaning, since coal is naturally hydrophobic and minerals are generally hydrophilic. Because of coal’s hydrophobicity, froth flotation has employed mostly non-polar oil collectors such as kerosene, crude petroleum, fuel oil. and certain coal-tar distillates (Wójcik et al., 1990; Solov'eva and Muklakova, 1995; Petukhov, 1995). The collector disperses into droplets in the pulp, and these droplets collide with, adhere to, and coat the coal particles, thus increasing their hydrophobicity (Polat et al., 2003). Dispersing these non-polar oils is often difficult, and the size of the oil droplets is often large. This results in high collector consumption and poor flotation performance. Investigating means of decreasing the collector dosage and cost are therefore of interest. Non-polar oils can be dispersed into smaller droplets by emulsification (Duong et al., 2000; El-Shall et al., 2000; Laskowski, 1992; Laskowski and Wang, 1997; Song et al., 1999). Emulsions are mixtures in which small droplets of one phase are dispersed in another. They are thermodynamically unstable, so emulsified collectors are also unstable, and demulsification can occur during storage. Demulsification of collectors significantly reduces their separation efficiency. A special emulsification device with a complex structure and high energy consumption has been reported to mix and prepare unstable emulsified collectors; however, its application in the coal froth flotation industry is impractical (Jones et al., 1978). Microemulsions are transparent and thermodynamically stable. Similar to emulsions, they consist of a surfactant (or surfactant and cosurfactant), oil, and water. The cosurfactant is usually a short-chain alcohol with two (ethanol) to four (butanol) C atoms. The average droplet size of microemulsions is 5–100 nm, compared with hundreds of micrometres for emulsions (Huibers, 1996). Microemulsions are kinetically and thermodynamically stable, and thus can be formed spontaneously (Vollmer and Vollmer, 2001). Oils can be dispersed into smaller droplets by microemulsification. The spontaneous formation of microemulsions reduces the difficulty and energy consumption associated with preparation. Effect of microemulsified collector on froth flotation of coal