Electron bandstructure of kaolinite and its mechanism of flotation using dodecylamine as collector

The bulk electronic structure of kaolinite (001) plane was studied with quantum mechanical calculations. The CASTEP parameterization of ultrasoft pseudopotentials without core corrections was used to optimize the structure of kaolinite bulk and slab models. The results show that Fermi energy of kaolinite (001) plane is 3.05 eV, and the band gap is 4.52 eV. The partial density of states (PDOS) of kaolinite (001) plane indicates that Al—O and Si—O bonds on the mineral surface are highly polar. The oxygen atoms of hydroxyl groups in surface layer are capable of forming hydrogen bond with the head group of cationic collectors. The properties of dodecylamine (DDA) cation were also calculated by density function theory (DFT) method at B3LYP/6-31G (d) level for illuminating the flotation processes of kaolinite. Besides the electrostatic attraction, the mechanism between kaolinite and DDA is found to be hydrogen bonds under acidic condition. Foundation item: Project(2005CB623701) supported by the Major State Basic Research and Development Program of China; Project(50874118) supported by the National Nature Science Foundation of China; Project(2007B52) supported by the Foundation for the Author of National Excellent Doctoral Dissertation of China     

调心滚子轴承径向游隙的检查

介绍了调心滚子轴承径向游隙检查的3种方法,即塞尺滑动检查法、套圈滚动检查法和专用仪器检查法的特点及适用场合。采用塞尺滑动检查为主、专用仪器测量为辅的检查方法可有效地保证质量。     

M8861A改装及对20000CA型轴承内沟磨的影响

通过对老设备M8861A的改装和重新安排调心滚子轴承内沟磨削工序，使原磨削该类型轴承内沟的关键设备提高了生产效率，降低了消耗。介绍一项少投入多产出、保质降耗的技改项目。     

国内科技信息

抛物线少油煤粉直接点火及稳燃喷燃器通过省级鉴定抛物线少油煤粉直接点火及稳燃喷燃器,于１９９８年１２月２７日,通过河南省科委、河南省电力公司联合组织的技术及产品鉴定。鉴定会认为：ＳＺＷＰⅢ型抛物线少油煤粉直接点火及稳燃喷燃器设计新颖,利用抛物线的物...     

锂云母浮选捕收剂和抑制剂研究进展

近年来锂资源需求不断加大,锂云母作为锂资源的关键补充来源,对其浮选研究日趋重要。矿石中锂云母常与方解石、白云母、长石和石英等矿物共生,分选难度较大。因此,在分析锂云母矿物性质的基础上,综述了其浮选捕收剂和抑制剂研究进展。目前锂云母捕收剂主要有胺类阳离子捕收剂（伯胺、仲胺、季铵盐、醚胺和双子星胺类）以及将胺类阳离子捕收剂和阴离子捕收剂按照一定比例混合的组合捕收剂;锂云母浮选抑制剂主要针对常见钙质、硅质脉石体系开展调控,主要有水玻璃、六偏磷酸钠等无机抑制剂,草酸、单宁和木质素类等有机抑制剂以及组合抑制剂。指出合成新型锂云母捕收剂、组合捕收剂在锂云母/水界面吸附基础研究、组合无机与有机抑制剂抑制钙质、硅质脉石及其作用机制三大方面是未来锂云母浮选领域的研究重点。     

秘鲁含砷铜钼矿高效浮选试验研究

对秘鲁某含砷铜钼矿进行浮选性能研究。结果表明,以改性硫脲Mac-12为捕收剂、AH-1为砷矿物抑制剂,闭路循环浮选流程可得到含铜26.65%、钼0.637%、砷0.348%的合格铜精矿产品,其铜、钼、砷的回收率分别达到了88.15%、85.77%、33.80%。     

Inconel625合金堆焊层在海水中的腐蚀行为

本文采用失重法,电化学极化以及交流阻抗法研究Inconel625合金堆焊层在10℃海水中的腐蚀行为。结果表明,Inconel625合金堆焊层在海水中初期腐蚀速率较高,随后降低到0.0004mm/a。Inconel625合金堆焊层表面没有观察到点蚀孔,表面不存在钝化膜。合金堆焊层在海水中为均匀腐蚀,海水中浸泡90天耐腐蚀性能稳定。     

基于LABVIEW的调焦控制系统研究

开发了数字控制系统以实现对调焦系统的闭环控制,并对调焦精度做出分析,得出了实验考察环境因素对调焦精度的影响;搭建了一套调焦系统,分析调焦原理得出系统控制模型.利用LABVIEW开发了数字PID控制系统,结合统计学原理对实验数据做出分析评价;该数字控制系统实现了对调焦系统的闭环控制,达到了较高的调焦精度.同时发现,振动等环境因素对调焦精度有严重的影响,为了得到更高的精度,需要隔振系统等环境控制设备的支持.     

Flotation techniques for separation of diaspore from bauxite using Gemini collector and starch depressant

The floatability of diaspore and three kinds of silicate minerals,including kaolinite,illite and pyrophyllite,by a cationic Gemini surfactant as collector and starch as depressant was investigated as function of reagents concentration and pulp pH.Further studies of artificially mixed minerals and bauxite ore were also detailedly conducted.At last,the pre-desliming reverse flotation separation process was adopted.It can be concluded that the combinational use of a Gemini cationic collector and the starch dep...