Properties of paper coated with kaolin: The influence of the rheological modifier

The first part of this paper analyses the influence of the molecular weight and concentration of carboxymethyl cellulose (CMC) and of kaolin concentration on rheology of the coating colours and on paper properties coated with ultra lightweight coatings (ULWC). In the second part, relationships between the rheological characteristics of the coating colour formulations and coated paper surface quality was also studied.New indexes on paper roughness at micro-scale are presented (RZI and SRI). In general, they show good correlation with sheet gloss. A new gloss index (SGI) is presented, accounting for the contribution of gloss from machine direction (MD) and cross direction (CD). Porosimetry was used to access microstructural characteristics in order to correlate them with light scattering and gloss properties. The former property is closely related to Hg intrusion volume of the coated layer while gloss is related to surface porosity with pore diameters in the range of 7–15 μm as measured by Hg intrusion volume.     

高岭土在碳热还原氮化过程中的相变

系统研究了苏州高岭土碳热还原氮化合成SiAlON过程在不同温度下的相变。对试样的XRD、SEM以及EDXA分析结果表明 ,1 30 0℃之前 ,试样中没有氮化物生成 ,物相为莫来石、石英和方石英 ;1 30 0℃时 ,高岭土开始发生氮化反应 ,生成过渡型SiAlON和β SiAlON。此时 ,石英和方石英相基本消失 ;1 4 0 0℃时 ,过渡型SiAlON、β SiAlON和X SiAlON三相共存 ,β SiAlON有所增多并有少量刚玉相生成 ;从 1 4 50℃到 1 550℃ ,Z值为 3的β SiAlON成为惟一的氮化产物 ,与少量SiC和刚玉相并存。莫来石在 1 50 0℃时完全消失     

煅烧高岭土吸附Pb^2＋／SDBS／PNP三元共存污染物的研究

对比Pb^2＋,SDBS,PNP单元和三元复合后在煅烧高岭土上的吸附,探讨了在不同投加量、吸附时间、pH值下三元共存在煅烧高岭土上的吸附影响．结果表明：Pb2＋单元去除率为94．71％,三元复合后为85．50％;SDBS单元去除率为75．36％,三元复合去除率为84．04％;PNP单元去除率和三元复合去除率分别为64．24％,55．57％．表明三元复合对Pb2＋和SDBS的去除产生拮抗效应,而三元复合对PNP起到增强吸附的作用．由IR红外分析可知煅烧高岭土吸附三元复合污染物并没有引起结构的改变,吸附过程为物理吸附．     

煤系高岭土超细煅烧工艺革新探讨

淮北煤系高岭土蕴藏量丰富,开发超细煅烧高岭土是其发展的主要方向之一,本文从现有生产工艺出发探讨工艺革新改造之法。     

改性水玻璃在含高岭土复杂萤石浮选中的综合应用

河北某萤石矿中萤石与石英嵌布粒度细,共生关系复杂并含有高岭土,品位低、氧化程度高。生产中采用常规的高碱度水玻璃进行石英抑制,生产技术指标较差,严重影响企业的生存与发展。由于浮选尾矿碱度高,水玻璃等分散剂SS含量高达5 000～7 000 mg/L,回用时又会导致生产指标的恶化。针对上述问题,试验采用两段磨矿,中矿集中返回再磨的流程,精矿浮选流程中抑制剂改用改性水玻璃,有效抑制了细粒石英、长石等细粒脉石矿物。同时,在改性水玻璃的综合作用下,实现了尾矿水SS的快速沉淀,尾矿水可有效返回利用,不会对选矿指标造成影响,最终获得了CaF₂品位为97.27%、SiO₂含量为1.5%、CaF₂回收率为77.68%的萤石精矿产品,提高了精矿质量,为该选厂的实际生产提供了技术支持。     

对武安高岭土除铁工艺研究

河北武安硬质高岭土粉含Fe2O31.23%，经高梯度磁选后降至0.77%，再用Na2S2O3进行还原溶解后降至0.62%，白度提高了13％，本文介绍了流程及条件试验过程和结果。     

我国高岭土精选新工艺述评

本文重点从下列几个方面介绍和分析了我国高岭土精选加工工艺的最新进展：（1）景德镇陶瓷原料──高岭土和瓷石──精选试验线（500t／a）工艺流程的研究；（2）福建龙岩某矿可生产多种不同档次高岭土产品的复合工艺流程；（3）高岭土干法加工过程中粉体密相脉冲输送的基本原理和基本流程；（4）由美国设计的湛江年产13万t高岭土项目精选工艺的基本特点和先进装备。     

穿越高岭土化粘土岩层的竖井井筒掘进实践

本文介绍了某混合并在掘砌施工中穿越强高岭土化粘土层，这种复杂的工程水文地质条件下所采用的井筒支护设计原理及施工方法。     

利用高岭土制取聚合氯化铝和白炭黑的试验研究

本文较为系统地研究了利用高岭土制取聚合氯化铝和白炭黑的工艺流程。通过正交试验，成功地找到了制取聚合氯化铝较优的工艺条件，为我国高岭土的开发应用提供了一条新途径。     

The chemical bonding of copper ions on kaolin from Suzhou, China

Reactions of copper with kaolin are important in determining copper fate in the environment. Adsorption characteristics of Cu by the kaolin from Suzhou, China were investigated at varying Cu concentrations (0 to 100 mg/l), pH values (approximately 2 to 11) and temperature (25, 40 and 50 °C). Cu adsorption by the kaolin was well described by the Langmuir and Freundlich adsorption equations. The kaolin did not exhibit the adsorption maximum, 666.67 mg/kg, as determined by the linearized form of the Langmuir equation. The k_d values decreased exponentially with increasing initial Cu concentrations in the solution. A unit increase in pH resulted in approximately 8.47, 9.61 and 10.82% increase in Cu adsorption by the kaolin at the initial Cu concentration 5, 50, 100 mg/l, respectively. The pH₅₀ values increase with increasing initial Cu concentration. Desorption of Cu was well described by the linear model (y = 0.0917x + 0.7136) with correlation coefficient R² = 0.9994. Most of the adsorbed Cu is nonspecific adsorption; the mobility of Cu in the kaolin from Suzhou, China is high under low pH conditions.