Value addition of paper coating grade kaolins by the removal of ultrafine coloring impurities

Two kaolin samples from the southern part of Kerala (A and B) have been characterised. The colouring impurities present were found to be carbonaceous and ferruginous, being also present in ultrafine size ranges. Modern beneficiation techniques such as ultra flotation and high gradient magnetic separation (HGMS) have been carried out to reduce the level of these contaminants and to increase the brightness of the product clays. The results showed that nearly 70% of the ultrafine carbonaceous matter in A, which originally contains 0.13% carbon (as fixed carbon), could be removed by shear floc-flotation. HGMS treatment could remove ∼ 45% of the iron minerals (feed assay 0.58% Fe₂O₃). Sample B contained 0.32% Fe₂O₃ and 0.19% carbon. The shear floc-flotation was found to be the only effective method by which ∼ 75% of the carbon could be floated out. This sample did not respond to HGMS which may be because of the ‘structural’ nature of the iron present. Both the kaolins, after processing, were found suitable for paper coating. Another important aspect of this work is the establishment of maximum permissible level for carbon in paper coating grade clays since the standard specifications do not give any limiting value.     

Mechanism of Crystal Redistribution in a Sheet-like Magma Body: Constraints from the Nosappumisaki and Other Shoshonite Intrusions in the Nemuro Peninsula, Northern Japan

Processes of crystal separation in a magma heavily laden withcrystals without phase change are investigated from observationson frozen magma systems: Nosappumisaki and other shoshoniteintrusions in the Nemuro peninsula, Japan, for which the originof the crystals and the initial conditions are well constrained.The Nosappumisaki intrusion is 120 m in thickness and extendsfor more than 1·5 km. It exhibits a wide range of lithologicalvariation, principally as a result of crystal redistributionafter intrusion. Crystals in each lithology can be clearly dividedinto two kinds according to their composition and texture: thosepresent before the intrusion of the magma (‘phenocrysts’)and those that crystallized in situ after intrusion. From thevertical change in mode and size of ‘phenocrysts’,it is shown that (1) augite ‘phenocrysts’ were rapidlydeposited, with little overgrowth after intrusion, by significantcoagulation or clustering on a time-scale of more than a fewyears, and (2) plagioclase ‘phenocrysts’, definitelydenser than the melt but concentrated in the upper level, floatedby counter flow of massive deposition of augite ‘phenocrysts’.These results indicate that in a magma heavily laden with crystalsof a few millimeters in size (>20 vol. %), crystal–crystaland crystal–melt interaction play an important role inthe separation of crystals from the host melt. KEY WORDS: magma chamber; sill; crystal settling; plagioclase flotation; Nosappumisaki     

内蒙×××蓝晶石矿可选性试验研究

对内蒙×××蓝晶石矿采用脱泥-碱性介质浮选-磁选和脱泥-磁选-酸性介质浮选两种工艺流程进行可选性试验研究。结果表明,酸性介质浮选的分选效率和选择性较好。该矿采用脱泥-磁选-酸性介质浮选工艺流程,获得了较好的试验指标。     

硫化汞锑矿汞锑分离降铬工艺试验研究

采用１号降铬剂酷少量重铬酸钾进行汞锑分离,替代纯重铬钾汞分离工艺,在相同技术指标前提出下,大大降低了重铬酸钾药剂用量和选矿成本,使选矿废水排放中Ｃｒ（ＶＩ）的含量达到了环保要求。     

湖北省宜昌硅钙质磷块岩选矿工艺研究

湖北省宜昌硅钙质沉积磷块岩,是难选的中低品位沉积磷块岩,主要磷酸盐矿物为泥晶磷灰石,主要脉石矿物为白云石、石英、玉髓.从获得高品位精矿、高回收率选矿工艺指标的角度,对含泥量较高的中低品位硅钙质沉积磷块岩,进行选矿工艺研究。确定分级-反浮选（常温）最佳选矿工艺路线为：选矿技术指标为磨矿细度-0．074mm（-200目）,含量占67．7％,原矿品位P2O5 25．89％,精矿产率58．61％、品位P2O5 35．22％,回收率80．00％.通过工艺流程试验研究的论述,旨在向年轻的选矿工作者传达一种工作思路,同时对于选别同类型磷矿的矿山企业也有一定的参考价值、     

××碳酸盐型萤石矿选矿试验研究

通过对浙江××碳酸盐型萤石矿的条件试验及开路、闭路流程试验研究,在常温条件下,采用一次粗选六次精选、部分中矿集中再选、抛两个尾矿的选矿工艺流程,取得了较好的选矿指标.     

氯化钠浮选剂最佳合成条件研究

讨论了二种N -烷基吗啉类氯化钠浮选剂最佳浮选性能的合成条件 ,给出了研究结果。     

冈比亚石英砂矿无氟浮选提纯新工艺试验

通过对冈比亚石英砂矿进行无氟提纯新工艺的选矿试验 ,掌握了其主要矿物组成及化学成分 ,确定了“筛分预处理—二段浮选”为该石英砂矿提纯的较佳工艺 ,认为S·H·N和B·C·A是石英与长石及含铁矿物分离的最佳无氟捕收剂和辅助捕收剂 ,经大范围多因素筛选、小范围析因的条件试验 ,最终确立了较佳的石英砂矿无氟提纯新工艺及选别指标