Interaction mechanism of flocculants with coal waste slurry
Interaction mechanism of flocculants with coal waste slurry
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DOI：
10.1016/j.fuel.2005.06.005
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发表时间：
2006-02-01
期刊：
影响因子：
7.4
通讯作者：
Erkan, ZE
中科院分区：
文献类型：
--
作者：
Sabah, E;Erkan, ZE
煤尾矿是煤炭开采和选矿厂不可避免的副产品，在脱水和固液分离方面往往存在问题。多组分细煤尾矿与各种混凝剂和絮凝剂的相互作用在脱水过程中非常重要。 Tuncbilek 选煤厂废物由 81% 的无机固体组成，在所有 pH 值下表面负电荷占主导地位。由于悬浮液中存在无机离子，特别是充当天然混凝剂的 Mg2+ 和 Ca2+，因此在自然 pH 值为 8.3 时可获得最高的沉降率和浊度值（无需使用絮凝剂）。在自然 pH 值下添加中等和低电荷密度的高分子量阴离子絮凝剂，与非离子和阳离子絮凝剂相比，在较低剂量下产生更高的沉降速率。结果表明，阴离子絮凝剂的电荷密度对沉降速率和上清液浊度都有显着影响，且沉降速率随着阴离子度的增加而增大。具有高分子量和高阴离子电荷密度的阴离子絮凝剂产生沉降条件所需的足够尺寸的絮凝物，而具有低电荷密度的阴离子絮凝剂在澄清含有高稳定性粘土矿物的悬浮液中更有效。多价离子充当带负电的煤、石英和粘土矿物与聚合物阴离子基团（-CH2-(CH-C=O)-COO基团）之间的桥梁。非离子型絮凝剂需要比其他絮凝剂更高的剂量才能达到同等的沉降率；尽管在最常见的 pH 值下获得了出色的浊度值。对于 119.7 克/吨固体絮凝剂的剂量，较高电荷密度 (%70) 的阳离子絮凝剂在自然 pH 值下实现了良好的沉降率和较低的上清液浊度 (9.9 NTU)。提出了每种聚合物类型与尾矿不同成分的相互作用机制。 (c) 2005 Elsevier Ltd. 保留所有权利。
Coal tailings are the inevitable by-product of coal mining and preparation plants, and often are problematic in terms of dewatering and solid-liquid separation. The interaction of multi-component fine coal tailings with various coagulants and flocculants are important in dewatering processes. Tuncbilek coal preparation plant wastes are composed of 81% inorganic solids with negative surface charges dominating at all pHs. The highest settling rate and turbidity values without flocculant are obtained at natural pH of 8.3 due to the presence of inorganic ions in the suspension particularly Mg2+ and Ca2+ that act as natural coagulants. Additon of medium and low charge density anionic flocculants with high molecular weight at natural pH produced higher settling rates at lower dosages than nonionic and cationic flocculants. It shown that the charge density of anionic flocculants has a significant effect on both settling rate and supernatant turbidity, also the settling rate increases with increasing the degree of anionicity. Anionic flocculants having high molecular weight and high anione charge density produced flocs at sufficient size necessary for settling conditions, yet anionic flocculants having low charge density were more effective in the clarification of suspensions containing clay minerals of high stability. The multivalent ions act as a bridge between negatively charged coal, quartz and clay minerals with anionic groups (-CH2-(CH-C=O)-COO groups) of the polymer. Non-ionic flocculants required higher dosages than other flocculants to achieve equivalent settling rates; though excellent turbidity values were obtained in most common pH values. Cationic flocculants of higher charge densities (%70) achieved good settling rates and low supernatant turbidities (9.9 NTU) at natural pH for a dosage of 119.7 g/t-solids flocculant. An interaction mechanism of each polymer type with different components of the tailings is proposed. (c) 2005 Elsevier Ltd. All rights reserved.