Characteristics of cationic Red X-GRL adsorption by diatomite tailings

As secondary mineral resources, diatomite tailings(DT) got from the Linjiang region of China were prepared and characterized by SEM, XRF and XRD. Mono-factor experiments were carried out to investigate the effects of the operation factor, including contact time, adsorbent concentration, initial p H value of the dye solutions, adsorption temperature and initial concentration of cationic Red X-GRL(X-GRL) on the adsorption of X-GRL. The adsorption kinetics, isotherms, thermodynamics and mechanisms for X-GRL were also studied. It was efficient for DT to adsorb X-GRL from aqueous solutions, and it was even discovered to have higher adsorptivity for X-GRL than diatomite concentrate(DC) in our previous test. The adsorption processes fit very well with the pseudo-second-order model and the Langmuir isotherm equation. In addition, various thermodynamic parameters, such as standard Gibbs free energy(ΔG°), standard enthalpy(ΔH°) and standard entropy(ΔS°) have been calculated. From thermodynamic studies, it was seen that the adsorption was spontaneous and endothermic. The main driving forces of the physical adsorption on DT are electrostatic attraction. The reason why DT showed higher adsorptivity for X-GRL than DC was that there were more clay mineral particles within, which has a remarkable ability of dye adsorption due to its high surface area. DT as a cheap absorbent for X-GRL removal would replace or partially replace the activated carbon.     

硅藻土/碳酸钙复合吸附材料制备研究

本实验用生石灰和碳酸铵与硅藻土混合进行水热改性,合成具有一定力学性能且吸附性能良好的硅藻土陶粒。研究了制备过程中生石灰添加量、碳酸铵添加量、水热反应温度、焙烧时间及焙烧温度对陶粒强度及吸附性能的影响。结果表明:当硅藻土中生石灰的添加量为15%、碳酸铵添加量为15%,180℃水热反应6 h,并在125℃下焙烧40 min时,陶粒性能最佳,其散失率仅为4.41%,对阳离子红的吸附去除率可达到49.42%,饱和吸附量为247.1 mg/g。X射线衍射(XRD)与红外光谱(FTIR)分析表明:向硅藻土中加入生石灰和碳酸铵后,硅藻土陶粒中生成了碳酸钙物相。     

甘肃某细鳞片石墨矿选矿试验研究

甘肃某石墨矿属于鳞片石墨矿石,原矿固定碳含量较低,为4.48%,石墨鳞片较小。对该地区细鳞片石墨矿进行选矿试验研究,得出适宜的粗选条件为:粗磨磨矿细度为-0.074mm占63.52%、浮选浓度为27%、煤油用量为640g/t、2#油用量为110g/t、生石灰用量为2500g/t(即矿浆pH=9),粗精矿采用五次再磨六次精选流程进行开路试验、闭路试验,最终获得石墨精矿固定碳含量为95.70%,回收率为71.78%的选别指标,为该地区石墨资源的开发利用提供了技术依据。     

晶面活性对丁二酸调控α-半水硫酸钙晶体形貌的影响

晶体形貌决定了α-半水硫酸钙(α-HH)的物化性质与应用领域。本文采用第一性原理计算和Wulff构型理论揭示了晶面活性差异对丁二酸调控α-HH晶体形貌的影响。结果表明：α-HH的(204)晶面是晶体形貌调控的关键晶面。(204)晶面上Ca²⁺连续分布且密度高，导致(204)晶面活性高，有利于媒晶剂作用。丁二酸以O—Ca离子键形式环状吸附在α-HH的(204)晶面。α-HH的高活性晶面优先被媒晶剂吸附并抑制，使晶体形貌沿高活性晶面方向缩短，过量的媒晶剂使晶体各晶面生长均被抑制，实现晶体形貌调控。