硫酸/草酸体系下拜耳法赤泥中铁铝浸出行为的差异

为探清赤泥中的Fe、Al在硫酸/草酸体系中浸出行为差异,比较研究了两种酸浸体系下广西某铝厂拜耳法赤泥中Fe、Al的浸出规律及机制。主要考察了酸浸过程因素对Fe、Al浸出效果的影响,比较分析了最佳试验条件下拜耳法赤泥中Fe、Al在不同酸浸体系的浸出差异,并通过浸出动力学和热力学分析阐述了硫酸/草酸体系下Fe、Al的浸出过程机理。研究表明,试验条件下,硫酸对Fe、Al的浸出效果均优于草酸;酸性溶液中赤泥各元素的浸出具有阶段性,其中Al的浸出优先于Fe;硫酸/草酸体系中对Fe浸出的效果差异主要体现在无机酸酸根和有机酸酸根供电子能力和作用机制不同,对Al浸出的效果差异主要体现在对赤泥中铝氧化物的作用机制不同。这一发现对充分利用不同酸处理赤泥、优化分离提取赤泥中有价金属提供了新思路。     

离子型稀土矿浸出过程微细颗粒迁移规律及调控

离子型稀土矿在浸出过程中浸出剂与矿石表面水合机制较为复杂,颗粒间的桥式胶结因离子吸附交换过程中存在多种作用力与分散作用而容易发生断裂,从而使微细颗粒发生迁移和重新排列,并在孔喉处沉淀,产生堵塞现象,影响离子型稀土的浸出效率。为揭示离子型稀土矿在原地浸出过程中微细颗粒的迁移规律,并找到适宜的调控方法,以龙南足洞离子型稀土矿为研究对象,采用实验室柱式溶浸法,考察了浸出剂质量浓度、黏度、流速、水力梯度、矿体高度及矿体含水率对微细颗粒迁移的影响。结果表明,离子型稀土矿浸出过程微细颗粒的迁移是影响浸出效率的重要因素之一。在外力的作用下,微细颗粒在浸出过程中易随浸出剂发生迁移运动。当调控浸出剂质量浓度低于4%,浸出剂黏度不超过1.5 mPa?s,水力梯度小于0.75,浸出剂流速低于3 mL/min,原矿含水量大于11%时,矿体中微细颗粒迁移率较低,矿体渗透性保持良好,有利于浸出液的渗流和稀土离子的浸取。     

辉钼矿生物浸出研究进展

简要回顾了国内外钼矿生物浸出的发展历程,总结了钼矿生物浸出率低的原因。对钼矿生物浸出中的关键问题,即辉钼矿的可浸性、钼矿浸出的菌种、生物浸出的作用机理、钼离子对菌种生长的影响和沉淀对浸出的抑制作用作了探讨。此外,提出了浸矿菌种基因改良、多级生物反应器浸出和浸出体系溶液电位调控等辉钼矿生物高效浸出方法。     

氨法加压浸出钴铜氧化矿工艺

氨法浸出是基于目标金属与氨形成配合离子进入溶液,实现目标金属与部分杂质的分离,因此浸出过程具有选择性。对钴、铜与氨的配合机制及亚硫酸钠还原性能的影响因素进行了分析。结果表明:提高cNH3/cMe有利于形成稳定性高的钴、铜氨配合离子;降低cSO42-/cSO32-,提高体系pH可降低还原剂还原电位。实验过程采用加压氨浸工艺,在NH3-NH4+-H2O体系中浸出钴铜氧化矿中的钴和铜,研究了总氨浓度、氨铵比、液固比、浸出温度、还原剂用量对氧化矿中钴和铜浸出率的影响。结果表明,在总氨浓度7 mol.L-1、氨铵比2∶1、液固比6∶1、浸出温度100℃、还原剂亚硫酸钠用量为三价钴含量(摩尔比)4倍的最优条件下,钴浸出率可达到95.2%,铜浸出率可达到95.8%。浸出液后续处理工艺简单,氨及铵盐可实现闭路循环,对环境友好。     

湿法冶金提取分离铜镍技术研究进展

随着低品位铜镍伴生矿和二次资源逐渐成为铜镍冶金原料的重要组成,使得冶金过程中金属与杂质、金属与金属之间的纯化分离更加复杂。目前,湿法冶金技术以相对经济和环保优势,在铜镍提取、分离领域一直备受关注,本文从"浸出和萃取"两个过程阐述了国内外湿法冶金提取分离铜镍技术的研究进展。首先介绍了酸浸、氨浸和生物浸出等不同浸出介质对铜镍浸出效率的作用情况,并对各浸出方法的优缺点进行了总结和对比。指出氨浸出可利用氨与原料中铜镍离子络合,实现高选择性浸出、杂质少、便于后续的纯化富集,是未来绿色铜镍冶金的发展方向。同时,综述了不同浸出体系下混合铜镍之间萃取分离的作用机制以及对应的研究现状,着重分析了氨浸体系中铜镍二者高效萃取分离所面临的挑战和未来研究方向,尤其是开发高选择性萃取分离技术,以促进铜镍湿法冶金的研究和工业应用。     

硫代硫酸盐浸出金矿石中硫化物和二氧化锰的相互作用

在氨浸出体系和氨性硫代硫酸盐浸出体系中，研究了黄铁矿或黄铜矿和二氧化锰之间的相互作用。在氨性溶液和氨性硫代硫酸盐溶液中，有二氧化锰存在时，黄铁矿和黄铜矿的溶解速度得到提高。二氧化锰提高硫化物浸出作用适用于从黄铁矿精矿和硫化矿石中用硫代硫酸盐浸出金。在用硫代硫酸盐浸出硫化物包裹型金矿石过程中，加入少量的二氧化锰可改善金浸出动力学，并提高金的总浸出率，并且几乎不影响硫代硫酸盐的消耗。     

高硅质石煤钒矿浸出机理研究

对高硅质石煤钒矿进行工艺矿物学分析和在硫酸体系下浸出机理的研究。结果表明,钒钛矿及含钒金红石、硫钒铜矿在硫酸直接浸出以及添加氟化物条件下,钒均难以浸出;钒酸盐、褐铁矿在硫酸体系下,钒易于浸出,氢离子破坏其晶体结构;含钒云母类矿物采用硫酸直接浸出,钒浸出率低于50%,在添加氟化物条件下,钒浸出率高于90%。氟化物强化含钒云母类矿物的浸出机理是HF与F-形成络合离子,在H_3O~+的促进下,破坏硅酸盐矿物晶体结构中的Si-O键,实现钒的浸出,HF在浸出过程起催化作用。     

不同类型黄铁矿对微生物浸铀行为的影响

针对低硫铀矿生物浸出,采用外源添加黄铁矿强化微生物浸铀,开展三种不同类型黄铁矿对微生物浸铀的影响研究。结果表明:添加黄铁矿可有效降低浸出体系pH,为微生物提供相对良好的浸出环境;添加黄铁矿促进体系内Fe2+快速氧化和氧化还原电位值迅速升高;黄铁矿体系与未添加黄铁矿空白体系相比,铀浸出率提高1.73%～5.53%;添加黄铁矿可降低微区黄钾铁矾等沉淀形成。     

大洋多金属结核氨浸工艺影响因素研究

在低温水溶液条件下,以亚铜离子为催化剂,一氧化碳为还原剂,在氨性体系中,对日处理10 kg大洋多金属结核扩大试验的浸出行为影响因素进行研究。试验考察了浸出体系电位、金属离子浓度、温度、液固比等因素对有价金属浸出率的影响。结果表明,控制浸出体系的电位对维持较快的反应速度和较高的金属浸出率十分重要;溶液中的钴离子浓度对钴浸出率影响较大,随着溶液中钴离子浓度的增加,钴浸出率下降,镍离子浓度对镍浸出率的影响很小;液固比对镍、钴、铜浸出率的影响不显著;温度对有价金属浸出率有一定影响,最好控制在40~50℃。     

CO2+O2地浸采铀强化浸出试验研究

新疆蒙其古尔铀矿床CO2+O2地浸采铀工艺中,铀浓度与HCO3-呈显著的正相关关系,但经过浸出初期后,提高CO2加入量不能有效提升体系HCO3-浓度,而对多数地浸单元的矿化条件而言,HCO3-浓度也尚未达最佳浸出需求。为此在该矿床某采区,采用补加碳酸氢铵和提高CO2加入量相配合的工艺,开展了强化浸出试验。结果表明,强化浸出效果显著,该采区浸出液中HCO3-从850 mg/L提升至1 200 mg/L,单孔铀浓度提升1.73~44.33 mg/L,集合样铀浓度提升8 mg/L。将pH调控在6.2~6.3和降低O2加入量稳定SO42-浓度,能避免强化浸出过程中发生碳酸钙和硫酸钙的沉淀,抽、注流量也并未受到影响。该强化浸出技术在多采区应用取得了良好的浸出效果和经济效益,是对该矿床CO2+O2浸出工艺的进一步优化。     

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.