磨矿介质对钼精矿碳含量影响研究

分析研究了低铬合金铸球和复相球墨铸球中碳的赋存状态及其对普通钼精矿、57钼精矿和二硫化钼粉碳含量的影响,指出用浮选法生产低碳57钼精矿,一段磨矿介质不宜使用复相球墨铸球.     

青海省石墨矿地质特征及可利用性评价

青海省位于青藏高原东北部,青北属秦祁昆造山系,青南属三江造山系,成矿带青北属秦祁昆成矿域,青南属特提斯成矿域,石墨矿较为丰富。省内石墨矿床主要分布于青北秦祁昆成矿域柴达木周缘地区,该区元古代变质老地层分布较为普遍,成矿地质条件优越,发现了众多的区域变质型晶质石墨矿床（点）,找矿前景较好。对柴达木周缘地区成矿地质背景、石墨矿分布以及典型石墨矿床地质特征、成矿规律、成矿远景区、成矿地质条件、成矿时代、成矿温压条件、碳质来源、矿床成因、成矿模式进行了研究,并对区内石墨矿的可利用性进行了评价。研究表明：①柴达木周缘石墨矿的赋矿地层柴北缘主要为古元古代达肯大阪岩群,柴南缘主要为古元古代金水口岩群,富含有机质,碳同位素测定表明,碳质来源为地层沉积的有机质;②石墨矿沿元古代变质老地层及构造带分布,受岩浆活动影响,规模总体一般,但矿化规模较大,矿体规模一般,品位较高,矿石质量一般;③柴达木周缘主要可以划分为3个石墨成矿带、4个成矿亚带、6个成矿有利区段;④柴达木周缘晶质石墨矿的成矿阶段可以划分为沉积成岩阶段、区域变质作用阶段、构造-岩浆叠加改造作用阶段,具有区域变质+构造-岩浆改造的特征,成矿温压条件具备,成矿时代为加里东期,矿床成因属区域变质型石墨矿床;⑤大通沟南山、黄矿山北和巴勒木特尔等地区的晶质石墨矿床选矿回收率较高,有一批具有工业价值的区域变质型石墨矿床,可利用性良好。     

The result of a wall failure in-pile experiment under the EAGLE project

The WF (wall failure) test of the EAGLE program, in which 2 kg of uranium dioxide fuel-pins were melted by nuclear heating, was successfully conducted in the IGR (Impulse Graphite Reactor) of NNC/Kazakhstan. In this test, a 3 mm-thick stainless steel (SS) wall structure was placed between fuel pins and a 10 mm-thick sodium-filled channel (sodium gap). During the transient, fuel pins were heated, which led to the formation of a fuel-steel mixture pool. Under the transient nuclear heating condition, the SS wall was strongly heated by the molten pool, leading to wall failure. The time needed for fuel penetration into the sodium-filled gap was very short (less than 1 s after the pool formation). The result suggests that molten core materials formed in hypothetical LMFBR core disruptive accidents have a certain potential to destroy SS-wall boundaries early in the accident phase, thereby providing fuel escape paths from the core region. The early establishment of such fuel escape paths is regarded as a favorable characteristic in eliminating the possibility of severe re-criticality events. A preliminary interpretation on the WF test results is presented in this paper.     

Wear of Carbon-type Seal Materials with Varied Graphite Content

Most carbon-type seal materials contain graphitic carbon as the minor constituent. Materials having graphite carbon as the major constituent were studied as possible seal materials at 10,000 feet per minute sliding velocities, in most experiments the temperature of the mating surfaces was 500°F. Carbon materials made graphitic by electro-graphitization were too soft; they gave high wear and high friction. Bodies molded with high-graphite-content materials and made hard by improved molding methods and impregnation gave acceptable friction and wear properties.

When a hardenable stainless steel was used, the effect of varied hardness of mating surface on wear of typical carbon was slight. Within a limited range, roughness of mating surface is not important to wear of carbons.     

Influence of date palm fibre and graphite filler on mechanical and wear characteristics of epoxy composites

In this article, mechanical and tribological performance of the epoxy composites based on graphite filler and/or date palm fibre are comprehensively discussed. The influence of the date palm fibre and/or graphite filler on the microstructure of the materials, tensile fracture samples, and worn surface of tribological samples are examined using scanning electron microscopy. The results revealed that interfacial adhesion of the date palm fibre with the epoxy is the key of the mechanical and tribological performance of natural fibre/polymer composites. The addition of the graphite is highly recommended for the natural fibre/polymer composites which can assist to reduce the friction which in turn enhances the wear characteristics of the polymer composites; however, the high content of the graphite deteriorates the mechanical properties.     

Influence of graphite and quartz addition on the thermo–physical properties of bentonite for sealing heat-generating radioactive waste

Bentonite is one of the most favored buffer materials for the deep geological disposal of waste in clay and granite formations all over the world. Buffer material, used to isolate heat emitting waste canisters, has to take up a strong heat load. This paper presents results of investigations on enhancing the heat conduction within the bentonite sealing. Admixtures of quartz and graphite accelerate the heat transfer into the host rock. Test samples consisting of different bentonite–quartz and bentonite–graphite mixtures were prepared. The thermal conductivity was determined as a function of admixture content, temperature, water content, and sample density within 35° to 140 °C at a uniaxial pressure of 2 MPa. The necessary conductivity could not be achieved with quartz, but the addition of graphite led to a suitable thermal conductivity. A set of equations was developed for the calculation of the thermal conductivity and the design of an engineered geotechnical barrier with heat conduction properties similar to those of the particular host rock.     

浙江石墨矿物学特征的初步研究

本文主要就广泛分布于浙江变质岩区的石墨，通过Ｘ光衍射分析，差热分析等矿物学研究方法，研究了石墨的石墨化程度，菱面体多型含量和氧化温度及它们之间的相关性。     

激光涂复层裂纹及其磨损性质的研究

本文着重对激光涂复层型纹及其形成机理进行了研究，并分析探讨了涂复层裂纹倾向对其耐磨性的影响关系。为球墨铸铁激光涂复涂层材料的选择以及激光涂复工艺的制定提供实用性经验。     

膨胀石墨横断面结构的初步研究

借助于光学显微镜对膨胀石墨蠕虫的横断面结构进行了初步研究，结果表明：可膨胀石墨在膨胀过程中主要存在沿Ｃ轴均衡膨胀和沿Ｃ轴扇形膨胀两种膨胀形式。膨胀石墨的孔结构与活性炭之间存在明显的差异，提示膨胀石墨与活性炭在吸附特性上应有所差别。