广西大新锰矿选矿厂旧线破碎系统技改实践

针对中信大锰矿业有限责任公司大新锰矿分公司选矿厂旧线破碎设备老化,能耗偏高,产能低下等问题。在不改变原工艺流程结构的前提下进行技术改造,主要进行设备更新。选用技术性能优良的关卓C80型颚式破碎机,关卓GP100S型圆锥破碎机,关卓HP100型圆锥破碎机,山特维克LF1850振动筛,提高破碎、筛分效率,减少循环负荷,产能从30万t／a提高到50万t／a的同时,减少破碎成本0．77元／t,提高了选矿厂的经济效益。     

鲁中选矿厂选矿流程的合理设计

介绍了鲁中冶金矿山公司选矿厂设计和建设的全过程，以及从１９８５年９月建成投产至今的１０年生产实践，表明该厂的建设前期准备工作及选矿流程设计是正确的，从而使该厂取得了较好的生产技术指标和经济效益。     

广西化学选锰研究的进展

文章介绍广西化学选锰研究在处理难过矿石、综合回收和废酸利用等方面的进展．     

MODELLING OF DISC DRESSING FORCES

A new mathematical model of the dressing of grinding wheels by diamond disc dresser is developed. It predicts the dressing forces between the diamond grits of a rotating disc dresser and the grits of an alumina grinding wheel. This model is based on the fracture of grits, the fracture of the bond and the contact forces between the dresser and grits. It considers the kinematical influences and in particular speed ratio of the dressing process. Also a Weibull distribution was used to predict the probability of bond fracture. Dressing forces are measured experimentally and are compared with those calculated from the new model. Theoretical results closely match with the experimental findings. The dressing forces generated from this model provide a basis for further prediction of wheel topography and the grinding process.     

Dressing process model for vitrified bonded grinding wheels

A holistic dressing process model for vitrified bonded grinding wheels was designed. It regards the dressing process as a tribological system subjected to a complex load collective. The intensive analysis of the input variables and their impact on the system function led to new knowledge about the acting mechanisms. The model enables a qualitative prognosis of the grinding wheel topography, the dressing forces and the thermal dressing process load.     

Strategies for production of parts textured by grinding using patterned wheels

The functionalization of surfaces by introducing pre-engineered textures is a new requirement from industry. Surfaces more prone to promote micro-lubrication are being designed by engineers and incorporated into the components specification. The major challenge is to develop manufacturing methods able to produce these textures in a repeatable and economically viable way. The aim of this research work is to develop grinding strategies based on the method proposed in [1] for producing textured surfaces by grinding. The characteristics of the produced textures are measured and evaluated using new proposed parameters. The obtained results show the potential of this process solution for the production of micro pockets for hydrodynamic bearings application.     

Cylindrical grinding of bearing steel with electrolytic in-process dressing

Cylindrical surfaces are increasingly utilized in various areas, and related high-efficiency and high-quality fabricating technologies are of great importance and significant benefit to modern industry. To provide fundamental knowledge for the bearing industry, studies have been conducted on the use of cast-iron-bonded cubic boron nitride (cBN) superabrasive wheels, based on electrolytic in-process dressing (ELID) technique for realizing high-efficiency grinding of steel cylindrical workpieces. Therefore, in this investigation, experiments were carried out on an ordinary cylindrical grinder with a hydrodynamic spindle, and straight type grinding wheels of different grit sizes were used. The effects of grit sizes on surface roughness as well as waviness, roundness, and surface stress were evaluated in both the traverse and plunge grinding modes. Comparison of ELID grinding with other processes was also carried out. Mirror surface grinding of different materials was achieved with the #4000 CIB-cBN wheel. ELID grinding was confirmed to induce compressive stress and to be more cost effective for small batch production of larger components when it works in the traverse mode.     

Factors influencing the dressing rate of chemical mechanical polishing pad conditioning

The primary consumables in the chemical mechanical polishing (CMP) process are the polishing pad and the slurry. Among those consumables, the polishing pad significantly influences the stability of the process and the cost of consumables (CoC). Furthermore, the small holes on the pad surface will be filled by the reactant from the CMP process, and the surface of the pad will deposit hard glazing gradually. The glazing not only reduces the ability of absorbing slurry of the pad, but it also causes scratching on the work piece. In order to maintain the stability of the CMP process and return to an ideal pad surface status, we must condition the pad according to a regular time schedule. At the same time, if we use different pad conditioning factors, the dressing rate of the CMP pad will be different. Most important of all, we have to decrease the pad material abrasion due to the pad conditioning process. In conclusion, if we can understand the influence of the dressing rate and conditioning factors effectively, it will be useful for maintaining CMP process stability, extending pad life, and reducing CoC and non-processing time.     

三鑫公司选矿生产中存在的问题及措施

根据目前矿石性质选矿工艺流程现状,对选矿生产过程中存在的问题进行了分析,提出了相应的解决措施。     

甲壳素棉交织医用敷料的设计及性能测试

为了降低医用敷料的成本,采用缎纹组织和经纬交织的方法设计了新型医用敷料,并与两种纯甲壳素非织造布对比试样进行了比较、分析.结果显示,试验所设计的敷料在力学性能、吸湿透气性能和抗菌性能等方面均好于对比试样,贴皮肤面为甲壳素纱线的敷料结构发挥了甲壳素特有的性质,减少了甲壳素用量(仅为42.92%).由此认为新型敷料设计思路可行,实现了降低成本、满足医用性能要求的设计目的.