Composition and modes of occurrence of minerals and elements in coal combustion products derived from high-Ge coals
Composition and modes of occurrence of minerals and elements in coal combustion products derived from high-Ge coals
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高Ge煤燃烧产物中矿物质和元素的组成和赋存方式
DOI：
10.1016/j.coal.2013.11.004
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发表时间：
2014-01-01
影响因子：
5.6
通讯作者：
Zhao, Cunliang
中科院分区：
文献类型：
--
作者：
Dai, Shifeng;Seredin, Vladimir V.;Zhao, Cunliang
临沧三个大型煤成锗矿床的粉煤灰（中国西南部的云南），乌兰图嘎（中国北方的内蒙古）和斯佩祖格利（Primorye，俄罗斯远东），是独一无二的，因为它们高度富集的元素，包括高达（不含有机物）：4.66%Ge、2.12%As、1.56%F、1.22%Sb、0.56%W、0.56%Zn、0.55%Pb、0.13%Sn、0.12%Ga、0.056%Bi、0.04%Be、0.028%Cs、0.017%Tl和0.016%Hg。这些高浓度的元素在飞灰中是由于它们在原煤中的含量高，它们来自煤燃烧过程中的高挥发性。稀土元素和钇（REY）在煤燃烧过程中分馏。它们在飞灰中比在来自相应煤的炉渣中更富集。最大REY富集可能发生在来自袋式除尘器的细粒飞灰或来自静电除尘器的粗粒飞灰中。飞灰中的未燃碳主要有三种类型：（1）原始显微组分结构（丝质体和透明质体）保存完好的碳，（2）各向同性和各向异性碳，（3）次生细粒碳。最后一类未燃尽碳的特征是嵌入细粒含锗和其他矿物相。Ge氧化物（例如，GeO 2）是飞灰中锗的主要载体。然而，其他含锗矿物相也被确定，包括玻璃，钙铁氧体，锗在二氧化硅中的固溶体，可能还有元素锗或锗（锗-钨）碳化物，以及以前未知的复合氧化物，包括（锗，砷）O-x，（锗，砷，锑）O-x，（锗，砷，钨）O-x和（锗，钨）O-x。一些部分的Ge作为吸附物种出现在灰颗粒中的不同类型的未燃烧碳（类型1和2）中。(C)2013爱思唯尔有限公司版权所有。
The fly ashes derived from three giant coal-hosted Ge deposits, Lincang (Yunnan of southwestern China), Wulantuga (Inner Mongolia of northern China), and Spetzugli (Primorye, Russian Far East), are unique because they are highly enriched in elements, including up to (on an organic-free basis): 4.66% Ge, 2.12% As, 1.56% F, 1.22% Sb, 0.56% W, 0.56% Zn, 0.55% Pb, 0.13% Sn, 0.12% Ga, 0.056% Bi, 0.04% Be, 0.028% Cs, 0.017% Tl, and 0.016% Hg. These high element concentrations in the fly ashes are due both to their high levels in the raw coals from which they were derived and their high volatility during the coal combustion process.Rare earth elements and yttrium (REY) were fractionated during coal combustion. They are more enriched in fly ashes than in slag from the respective coals. Maximum REY enrichment may occur either in fine-grained fly ash from baghouse filters or in coarse-grained fly ash from electrostatic precipitators. Cerium and Eu are more enriched in the fly ashes than other REY, and yttrium is relatively depleted in the fly ashes in comparison with the slag.Three types of unburnt carbon can be identified in the fly ashes: (I) carbon with well-preserved initial maceral structures (fusinite and secretinite), (2) isotropic and anisotropic carbon, and (3) secondary fine-grained carbon. The last type of unburnt carbon is characterized by embedded fine-grained Ge-bearing and other mineral phases. Ge oxides (e.g., GeO2) are the major Ge carrier in the fly ashes. Other Ge-bearing mineral phases, however, were also identified, including glass, Ca ferrites, solid solutions of Ge in SiO2, and probably elemental Ge or Ge (Ge-W) carbide, as well as previously-unknown complex oxides including (Ge,As)O-x, (Ge,As,Sb)O-x, (Ge,As,W)O-x, and (Ge,W)O-x. Some portion of the Ge occurs as adsorbed species in different types of unburnt carbon (Types 1 and 2) in the ash particles. (C) 2013 Elsevier B.V. All rights reserved.