提高拜尔法格子磨磨矿效率的途径

本文结合氧化铝生产实际,通过分级设备、循环负荷、入磨矿石粒度等对磨矿效率的影响的分析,指出了完善和优化格子磨——旋流器一段闭路磨矿工艺和进一步降低入磨矿石粒度是提高磨矿效率的有效途径。     

如何有效提高拜尔法格子磨磨矿效率

本文结合我厂生产实际,通过对影响拜尔法格子磨磨矿效率因素进行分析,特别对分级设备、循环负荷、入磨矿石粒度等因素对磨矿效率的影响进行了分析研究,指出格子磨-旋流器一段闭路磨矿工艺经过完善和优化;进一步降低入磨矿石粒度,是山西分公司提高磨矿效率的有效途径,通过生产实践证明,格子磨加旋流器一段闭路磨矿流程是目前拜尔法原矿浆制备工艺提高磨矿效率,保证矿浆细度的最佳选择。     

磨矿浓度对磨矿产品粒度组成特性的影响

磨矿浓度是影响磨矿产品粒度组成特性的关键因素.根据柿竹园矿石性质,在实验室和工业试验中分别考察不同浓度下一段磨和二段磨的产品粒度组成特性.结果表明,实验室条件下一段磨矿浓度在75 %、二段磨矿浓度在65 %时能获得均匀性好、合格产品粒度粗和有用磨矿耗能低的磨矿产品质量.工业试验条件下一段磨矿和二段磨矿产品中合格粒级产率分别增加2.23 %和3.96 %、平均粒度分别加粗1.13 μm和3.8 μm,过粉碎分别减轻0.88 %、1.35 %,磨矿过程技术效率分别增加2.79 %、4.86 %,能耗利用率分别增加4.39 %、6.12 %.同时,分级溢流产品中合格粒级产率增加0.72 %,平均粒度加粗1.4 μm,过粉碎减轻6.76 %,分级溢流产品质量得到全面优化.对选矿厂而言,稳定磨矿浓度非常有必要.      

半自磨机排矿速度及粒度优化研究

半自磨机磨矿介质由钢球和矿石自身组成,随着矿石硬度及块度的增加,造成半自磨机排矿速度偏慢及排矿粒度组成不合理,影响系统台效及电力、钢球等消耗。半自磨机为强制排矿碎磨设备,可通过改变排料端设计,将直形排料端改为弧形结构,优化半自磨机的排矿速度及粒度组成,达到提高半自磨系统磨矿效率的目的。     

一九八二年云南省选矿述评

破碎、磨矿与分级在碎磨流程方面有人提出,为了提高磨矿效率,降低磨矿作业的投资和经营费,降低碎矿产品的粒度总是有利的,对难磨矿石效果更为显著。为了达到此目的,认为采用闭路碎矿更为合理。同时指出,对中型以上的选厂,无论粗磨还是细磨,选用R+B(棒磨+球磨)的流程都是有利的,并在大姚铜矿生产实践中得到证实。有的作者     

瓷球磨矿在行洛坑钨矿中的工业应用

本研究以福建行洛坑钨矿石为对象,研究了纳米陶瓷球作为磨矿介质在钨中矿再磨中的磨矿特征,并应用于钨中矿再磨作业。研究结果表明,球磨机使用瓷球作为磨矿介质可以对钨矿石进行有效破碎,工业应用可以达到原钢球磨矿时溢流入重选的产品细度要求,过粉碎现象较钢球磨矿明显改善,磨矿产品粒度分布特征更均匀,且不会有铁杂质产生,球耗从1.41 kg/t降至0.97 kg/t,电耗从8.21 kWh/t下降到5.78 kWh/t,节能降耗效果明显,取得了良好的经济效益,因此,纳米陶瓷球可以取代钢球作为钨中矿再磨的磨矿介质。     

钢锻作细磨介质下的磨矿能耗与粒度分布特征

钢锻是一种线接触为主的磨矿介质.以1.18~2 mm、0.6~1.18 mm、0.3~0.6 mm 3个粒级样以及实际生产二段沉砂样为研究对象,分别采用等质量的钢球和钢锻进行分批次磨矿试验,分析了其磨矿产品的粒度分布和磨矿能耗分布.结果表明,钢锻作为细磨介质,与钢球相比,磨矿产品有着相同的粒度分布规律,符合JK粒度破碎模型.但在相同磨矿条件下,钢锻磨矿时生产能力比不上钢球.但随着给料粒度的变细,钢锻的磨矿效果开始显现,其磨矿产品中P80值与钢球的差异相差为0.22 %,而t10值与钢球的差异相差为2.23 %.与此同时,磨矿产品中 < 0.010 mm的含量明显低于钢球,过粉碎轻.当采用 < 0.425 mm实际钨矿石作为入磨样品验证时,有着上述相同的结论,从理论上说明了钢锻虽然磨矿能力逊色于钢球,但钢锻产生的合格粒级含量高于钢球,过粉碎情况轻于钢球,对于脆性矿物的细磨是一种优良的磨矿介质选择.      

矿石细磨过程的钢球尺寸研究

通常将磨矿粒度0.074毫米以下的磨矿泛称为细磨。目前,对于嵌布粒度细微的矿石,要提高回收率,必须进行细磨,如云锡公司的细粒锡石回收,老尾矿处理等。而影响矿石细磨过程的因素是多方面的,其中,钢球尺寸是一个很重要的因素。本文在对云锡矿石细磨的研究基础上论述钢球尺寸对细磨过程的影响及研究如何确定细磨的钢球尺寸。     

某大型金矿提高半自磨-球磨回路产能的参数研究

针对金矿选厂的磨矿流程的磨矿效率低、磨矿功耗大等问题进行技术分析,根据现有磨矿设备的规格及对磨矿产物细度的要求,综合现有生产工艺、矿石性质、选矿技术和磨矿设备等因素,运用JKSimMet软件进行磨矿回路的稳态模拟,预测利用现有磨矿回路处理岩芯样时改善选矿细度、提高磨机产能的可能性。研究结果表明,扩大磨机回路产能的瓶颈在于半自磨机,减小半自磨机给矿粒度可显著提高半自磨机和球磨机的磨矿效率,使磨矿回路的处理能力最大能提高35%。     

焦家金矿磨矿介质配比优化试验研究与应用

针对焦家金矿选矿厂球磨机单位球耗高、磨机效率偏低和磨矿产品粒度组成不均匀等问题,基于矿石力学性质和磨矿循环产品粒度分布,采用段氏球径半理论公式计算得到推荐方案介质配比,并建立对照方案进行实验室磨矿对比试验,最终确定初装球方案为:Φ90:Φ70:Φ50:Φ40:Φ30=15:25:20:15:25.2016年10月26日...     

转炉炉壳热应力分析

根据实际转炉建立实体模型。以有限元为手段,考虑了炉衬和炉壳材料的物性参数随温度变化的特点和炉衬与炉壳之间膨胀间隙,计算了转炉炉壳在温度载荷和炉衬膨胀压力同时作用下的热应力。所得结果可为转炉炉壳设计提供依据。     

焦炭热性能指标意义浅析

通过对焦炭在高炉内的历程及其变化规律的剖析,阐述焦炭热性能指标的意义,形象地把焦炭在高炉内的损耗分为三部分(M1,M2,M3)。指出M2对焦比及焦炭价格有一定的指导作用。     

Results of treatment of cancer of the cardia

Cancer of the cardia is traditionally discussed with cardiac cancer of the lower portion of the esophagus and upper gastric cancer invading the esophagus, and the specific characteristics of cancer of the cardia have never been clearly defined. We reviewed the outcome of 172 patients with adenocarcinoma of the cardia who had undergone radical surgery between 1949 and 1994 in the Division of Gastrointestinal Surgery of the Cancer Institute Hospital. The centers of the tumors were located within 2 cm above and below the boundary between the esophagus and the stomach, and their longitudinal diameter was less than 8 cm. We divided the patients into an early period (1949-1979; n = 79) and a late period (1980-1994; n = 93), and focused on the historical transition. There were no differences in patient gender or histology between the two periods. However, the late period was associated with fewer cases of esophageal invasion and shorter longitudinal diameter, as the age of the population advanced. The number of advanced cancers such as the localized and infiltrative type had decreased, and early cancer and early clinical stage had become more common, but despite the fact that the number of early cancers had increased, extended dissection, such as thoracic and paraaortic lymph node dissection, was performed more frequently. By clinical stage, the long-term outcome markedly improved in Stage I patient in the late period, and tended to improve in Stage II and III patients. This appears to have been attributable to the prevention of micrometastasis by extended dissection, although the number of early cancers is another major potential cause. There were no differences in the outcome of Stage IV patients between the two periods, and further advances in multimodality therapy must be awaited. The range of resection is basically proximal gastrectomy, and if there are adequate indications, the prognosis is favorable. In view of the status of lymphatic flow and lymph node metastasis, and long-term results, lateroaortic lymph node dissection is important. Since the number of early cancer patients has been increasing, if intraabdominal recurrence is prevented, intrathoracic lymph node dissection will contribute greatly to the outcome of such patients.     

The effect of amount of possession of the trait of hostility on accuracy of perception of hostility in others.

Some theories of personality hold that an individual's perception of others is influenced by his own personality characteristics; more specifically, that a trait of low social value will be projected more into others, and that insight into the possession of these characteristics reduces this distortion. These 2 hypotheses were tested by having a group of college students rate each other (including themselves) on degree of friendliness or hostility. Agreement with group rating about self yielded the insight score. In general, the hypotheses were supported; the "friendly" Ss were most accurate in their perception of others, and insight was positively associated with accurate perception. From Psyc Abstracts 36:04:4HL16M. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Comparison of rates of infection of two methods of emergency ventricular drainage

The rates of infection of two methods of external ventricular drainage in use at Atkinson Morley's Hospital--namely, (a) percutaneous drainage with Rickham reservoirs and (b) tunnelled ventriculostomies--were compared in this retrospective review. Percutaneous drainage of CSF with Rickham reservoirs was associated with a 27% rate of infection as identified by positive microbiological cultures; tunnelled ventriculostomy catheters had a 10% infection rate. The difference in the infection rate between the two methods was statistically significant (P < 0.015). Other variables examined, including the age and sex of the patients and the reasons for ventricular drainage, were not associated with an increased rate of infection. Most infections from either method were caused by a coagulase negative staphylococcus. The average duration of ventricular drainage before identification of positive cultures was 5.7 days for Rickham reservoirs and 6.0 days for ventriculostomies.     

浅析《野草》的版画特征

鲁迅先生一生热爱美术作品,对版画中木刻兴趣尤甚.<野草>作为其"写心之作",亦呈现出一些与木刻版画一致的审美特征:一是具有木刻版画的色彩特征,多对比、多冷色,有阴郁的美感;二是具有木刻版画的力度特征,环境描写、人物刻画处处刀锋毕现,遒劲有力,有一种"力之美".     

四辊破碎机车刀架的改造

针对四辊破碎机车刀架车削中存在的几个问题,详细介绍了电动车刀架的结构和工作原理,建立主要设计参数的数学表达式,并进行适当的分析。改造后,这种电动车刀架运行平稳、可靠、方便、省力,取得了预期的效果。     

Effect of antibiotics of chemotaxis of human leukocytes

The effect of 20 different antibiotics on chemotaxis by human neutrophils was studied. Human leukocytes incubated with chloramphenicol, rifampin, sodium fusidate, and tetracyclines in vitro showed markedly depressed migration. The mechanisms by which these antibiotics affect leukotaxis are discussed.