热处理低温钠长石的EPR和X射线衍射研究

利用电子顺磁共振(EPR)和X射线衍射方法研究了天然和热处理钠长石单晶。热处理在500—850℃水热条件下完成。在外加磁场B平行于晶体c~*轴的方向上,测量了加热前后Fe^(3+)的EPR谱和线宽△B随温度和加热时间的变化。结果显示,线宽随Al、Si无序的增大而增加。由此得出结论,在低温钠长石中,Fe^(3+)位于Al^(3+)占据的T_1(o)位置,在被研究的温度范围内,Fe^(3+)未参与四面体位置T间Al、Si交换。谱线的加宽主要是由在Fe^(3+)邻近位置上Al、Si无序的增大引起的,同时与观测到的晶胞参数变化有关。在Al、Si无序更强的晶体中,Fe^(3+)谱变得极宽。

硼镁铁矿碳热还原的研究

用 MoSi_2电炉、高频感应电炉加热,在石墨坩埚里进行了硼镁铁矿碳热还原研究。探讨了在 1 450—1 800℃ 温度下矿石中有价值元素 Fe,B,Si,Mg 在碳热还原过程中的行为。结果表明,在 1 500℃以下主要是铁的还原;随着反应温度的提高,进入合金相中[B],[Si]含量增加。在 1 800℃ 左右,有利于B,Si 的还原,并有少量 MgO 被还原,合金相中碳的溶解度随[B],[Si]含量的增加而减少,而碳的活度系数γ_c却增大。反应平衡时,a_c≈1。

Changes in organic structure and mineral phases transformation of coal during heat treatment on laboratory scale

Structural changes due to coalification and oxidation influence the coal quality, geochemically and petrologically. Understanding of the coal structures helps to predict the behaviour of coal at various processes. The objective of this paper is to study the changes in organic structure and mineral phase transformation during combustion. Different density fractions were generated and then heated at different temperatures from 200 to 1000 ℃. Petrography, Fourier transform infrared spectroscopy （FTIR） and X-ray diffraction （XRD） were carried out on all the density fractions aimed to accomplish this objective. Here, through petrography, it was observed that the vitrinite and liptinite macerals disappear at higher temperature while porous inertinite is seen. The inertinite structure is exposed which is assumed by the presence of -OH and C-O-C stretches with the aromatic nucleus （CH） and three to four adjacent H from FTIR spectra. Moreover, it can be concluded that aliphatic groups get collapsed at high temperature. In case of inorganic matter, through XRD and FTIR, it is also revealed that with increasing temperature, clay minerals converted into elemental oxides. Hence, this study is suggesting that the structures of coal are altered by the degree of contact metamorphism.

离子吸附型稀土矿石加热过程中稀土变化特征

以广西容县某离子吸附型稀土矿为研究对象，矿石经低温（自然风干、60℃和120℃）和中温（240℃）四个温阶加热处理，采用ICP-AES分析矿石中稀土含量，结果表明：①120℃时，全相稀土损失率平均为2．11％，离子相损失率平均为2．18％，表明此温度对稀土影响较小，加热去除水分是可行的，加热温度是60℃～120℃。②与自然风干相比，加热后矿石中全相、离子相稀土均呈减少趋势。240℃时，离子相损失率为2．69％～16．51％，平均11．43％；全相损失率5．10％～9．12％，平均7．24％。③离子相稀土组分随温度升高，La和Ce配分增高，Er，Tm，Yb和Lu降低。低温、中温加热过程中可能不存在离子相与全相稀土相互转换过程；矿石中吸附水和自由水的去除不是稀土减少的原因；减少的稀土离子可能在蒙脱石层间发生同晶置换。