稀土分离厂生产废水中化学需氧量的测定

水和废水监测分析方法规定 ,测定工业废水的化学耗氧量时 ,需要采用重铬酸钾法 ,记为CODCr。测定时 ,由于氯离子会干扰测定 ,影响测定结果 ,需要在回流前向体系中加入一定量硫酸汞 ,络合氯离子以消除干扰 ;这种方法氯离子的干扰上限为 2 0 0 0mg·L- 1 。广东珠江稀土有限公司生产排放废水为稀土矿物提炼废水 ,其氯离子含量通常在 16～ 19g·L- 1 之间 ,含量较高。按国家环保局制定的“废水中化学需氧量的测定”标准方法进行测定时 ,会使测定结果大大偏高 ,针对这种情况 ,我们在国家标准方法的基础上通过改变反应条件 ,在几个方面进行了反复试验 ,得到了切实可行的分析CODCr方法 ,方法的精密度和准确度较好 ,分析数据令人满意 ,该法得到环保部门的认可     

工业废水中COD的无汞盐法测定

采用无汞盐法对工业废水即COS进行了分析。本方法提出以硝酸银消除氯离子的干扰,在硫酸-磷酸介质中快速测定COD,避免了汞的二次污染,试剂用量少,回流时间短,精密度和准确度较高,与标准方法比较,结果可靠,具有一定的环境效益和经济效益。     

不同介质AAS法测定银精矿中的银

根据银离子能与氯离子、氨离子、硫脲结合形成可溶、稳定的络合物,实验了在不同浓度的盐酸介质、氨水介质、硫脲介质中测定银精矿中的高含量银,其测定范围大于5 000 g/t,确定了AAS法测定高含量银时各介质的最佳浓度范围。经银精矿样品验证及标准物质加标回收实验表明,分析结果准确、可靠,能满足选冶工艺生产的要求。     

原子吸收光谱法测定铜精矿中微量银

对湖南省麻阳铜矿铜精矿产中的微量银作了原子吸收光谱法测定试验，研究了铜对银的测定干扰，并提出了消除干扰的方法，分析方法准确度与经典方法一致。     

COD_(Cr)测定中氯离子干扰、消除及废银回收

本文研究了COD_(Cr)测定时氟离子的干扰及消除方法,克服汞造成的二次污染,以及废银的回收方法。     

铅试金重量法结合原子吸收光谱法测定银钯精矿中银

采用硝酸、盐酸、高氯酸分解样品,加入盐酸与银反应形成氯化银沉淀后过滤,采用铅试金重量法对沉淀中银量进行了测定,并扣除了钯产生的干扰,同时采用原子吸收光谱法(AAS)对滤液中的银量进行了测定,将沉淀与滤液中的银量相加后除以样品量得到样品中银的含量,实现了铅试金重量法联合原子吸收光谱法对银钯精矿中银的测定。考虑到在沉淀形成的过程中,氯化银沉淀对铂和钯有严重的吸附作用,因此考察了铂和钯对沉淀中银量测定的影响。试验表明,采用铅试金法对沉淀中贵金属进行捕集后,贵金属合粒中的铂对银测定的干扰可忽略不计,但钯的干扰不可忽略。实验采取用10mL硝酸(1+1)低温溶解贵金属合粒,以原子吸收光谱法测定合粒溶液中钯量,从铅试金重量法所得结果中扣除合粒中钯量的方法消除了沉淀中钯对测定的干扰。干扰试验表明,滤液中的主要共存元素钯、铜、铋、金、铂对样品中银测定的干扰可忽略不计。按照实验方法,对钯银精矿样品中银平行测定11次,相对标准偏差(RSD)为0.028%~0.059%,同时加入高纯硝酸银进行加标回收试验,回收率为98%~102%。将实验方法应用于银钯精矿样品中银的测定,其测定结果与碘化钾电位滴定法基本一致。     

电感耦合等离子体原子发射光谱法测定铅矿、锌矿和铅锌矿中杂质元素

用盐酸和硝酸的混合酸溶解试样, 电感耦合等离子体原子发射光谱法测定了铅矿、锌矿和铅锌矿中的铅、锌、镉、汞、砷、锰、银、铜、铁杂质元素含量。根据分析线的选择原则, 结合待测元素的检测范围, 选择了无干扰或干扰小、谱图峰形对称、灵敏度高的谱线作为分析线。研究了共存元素间的干扰, 结果表明共存元素间不存在干扰。所建校准曲线的线性相关性好, 相关系数(r)在0.999 5～1.000 0之间。方法用于铅精矿、锌精矿、铅锌矿标准物质的测定, 测定结果用MEF法检验, 方法无恒定系统误差和无相关性系统误差, 测定值与标准值无显著性差异。方法的试剂用量少、分析速度快、线性范围宽, 可用于铅矿、锌矿、铅锌矿中镉、汞、砷、锰、银、铜、铁、铅、锌的同时测定。     

工业废水中化学需氧量的测定方法对比

本文对工业废水中化学需氧量测定的两种方法,重铬酸盐法及COD快速消解分光光度法进行了试验对比,在样品的采集与保存、样品试份的代表性、干扰物的消除等各方面作以分析,对两种方法的检出限、检测下限及准确度与精密度进行试验测定。结果表明,重铬酸盐滴定法测定化学需氧量测定准确度更高,适用于实验室出具具体报告的精准分析;快速消解分光光度法测样时间短,消耗试剂少,在生产指导方面具有明显优势。     

纸层析分离-双硫腙分光光度法测定岩石、矿物及合金中的银

目前,用双硫腙比色法测定岩石、矿物、合金中的银是较常用的方法。此法在大量掩蔽剂存在下受汞、金、铜、铁等元素的干扰。本文介绍利用纸上层析法,将银固定到原点上与其干扰离子分离,然后在一定量的乙二胺四醋酸存在下,用双硫腙法进行测定。这样不仅能消除与双硫腙作用的元素     

碘化钾碱性高锰酸钾法测定稀土冶炼废水COD时的K值

本文通过实验研究,采用稀土冶炼废水中的主要还原性物质(草酸)配制水样,分别采用碘化钾碱性高锰酸钾法、重铬酸钾法测定水样中化学需氧量(COD)值,确定两者之间的比值K,以便将碘化钾碱性高锰酸钾法的测定结果CODOH-KI换算成重铬酸钾法的CODcr,来衡量稀土冶炼废水中的有机污染物状况,供环保部门对稀土冶炼企业进行环境执法与监督时参考。     

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)     

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.     

Quality of life of relatives of mental patients

Usage of quality of life of psychiatric patients' relatives as the parameter of estimation of the quality of psychiatric care is considered. By means of standard questionnaire elaborated by the authors as well as by means of both individual and group conversations the quality of life was analyzed in 40 relatives which lived together with psychiatric patients. Different spheres of their life and difficulties (financial, social-psychologic, production) were examined in families with such patients. The defects of psychiatric care that had direct influence on the quality of life of the psychiatric patients' relatives are outlined.