电感耦合等离子体原子发射光谱法测定氧化钼中镧和钇

氧化钼掺杂稀土元素改性是近年来的研究热点,目前尚没有针对氧化钼中稀土元素分析的国家标准方法。实验采用硝酸-过氧化氢溶解样品,使用电感耦合等离子体原子发射光谱法(ICP-AES)测定氧化钼样品中镧和钇。实验研究了样品溶液中钼基体和试液介质酸度的影响,结果表明:高浓度的钼对镧和钇的测定产生基体效应,而氧化钼质量浓度小于2 mg/mL时对镧和钇的测定几乎没有影响;介质中硝酸酸度不影响样品中镧、钇的测定。按照实验方法测定含镧量不同的4个样品中镧,测定结果的相对标准偏差(RSD,n=7)为0.95%～3.2%,回收率为97%～98%;按照实验方法测定含钇量不同的4个样品中钇,测定结果的相对标准偏差(RSD,n=7)为4.3%～5.5%,回收率为101%～103%;镧和钇的测定值与参考值相吻合。     

电感耦合等离子体原子发射光谱法测定钛合金中镧铈钇

研究了用电感耦合等离子体发射光谱法(ICP-AES)测定钛合金中镧、铈和钇的条件并建立了分析方法。样品用硫酸或硫酸-氢氟酸溶解, 选择398.852 nm、394.274 nm和371.092 nm波长谱线分别作为镧、铈和钇的分析线, 基体效应对测定的影响采用基匹配方法消除。镧、铈和钇校准曲线的线性范围(质量分数)分别为0.001%～0.030%、0.005%～0.030%和0.001%～0.030%, 线性相关系数均为0.999 9, 检出限分别为0.003 μg/mL(镧)、0.015 μg/mL(铈)和0.001 μg/mL(钇)。对硫酸和硫酸-氢氟酸的溶样效果进行比较, 表明两种溶样方法都能实现镧、铈和钇的准确测定, 但硫酸-氢氟酸的溶样速度快, 可提高分析效率。在不含镧、铈和钇的钛合金样品中加入不同量的镧、铈和钇标准溶液进行精密度和加标回收试验, 测得镧、铈和钇的RSD值分别小于或等于1.7%、7.3%和0.59%, 回收率在92%～100%之间。方法用于钛合金样品中钇和镧的测定, 测定值与ICP-MS法的测定值一致;用于钛合金标样中铈和钇的测定, 测定值与认定值相符。     

次灵敏线火焰原子吸收光谱法测定稀土-镁中间合金中镁

以镁的202.5 nm次灵敏线为分析线、火焰原子吸收光谱法测定了电解稀土-镁中间合金中的镁含量。考察了稀土基体及主要杂质的干扰情况,结果表明,钆、钇、钕3种稀土元素对镁的测定均有干扰,但在标准溶液中加入定量钆、钇、钕基体可消除干扰;测定溶液中主要杂质元素铁、铝、钨、钼的质量浓度在1μg/mL时,对10μg/mL镁的测定没干扰。镁的质量浓度在0~20μg/mL范围内呈良好线性关系。对钆-镁、钇-镁、钕-镁3种合金产品进行了检测并验证方法的精密度和准确度,RSD均小于2%,回收率在98%~102%范围内。本方法无需预先分离稀土,较常规EDTA滴定法简便、快速,适用于实际生产中量大而快速的检测需要。     

钢中钇化物电解分离方法研究

本文观察了低合金钢及18-8奥氏体不锈钢中钇化物的化学、电化学性质,探讨了影响定量提取钇化物的各种因素,如电流密度、电解温度、电解液极性、酸度以及络合剂的种类等。通过实验建立了钢中钇的分离分析方法,并对方法的准确度及回收率进行了检验。     

电感耦合等离子体原子发射光谱法测定硅铝钡锶合金中锶

探讨了用电感耦合等离子体原子发射光谱法(ICP-AES)测定硅铝钡锶合金中锶元素的分析条件并建立了测定方法。样品用盐酸、硝酸和氢氟酸溶解, 硼酸除氟, 试液经过滤后, 选择强度较大、峰形较好、干扰小和稳定性好的421.5 nm谱线作为分析线进行测定。结果表明, 锶浓度在0.001～0.025 mg/mL范围内线性关系良好, 线性方程为I= 11 551.75 ρ+72 706 384, 相关系数R²=0.999 9。对硅铝钡锶合金标准样品进行测定, 锶的测定值与认定值基本一致。硅铝钡锶合金实际样品中锶测定结果的相对标准偏差(n=10)为0.067%, 加标回收率为106%。     

离子色谱法测定黄金中钇

研究了离子色谱法测定黄金中钇(Y)的含量,考查了淋洗液的组成、浓度、pH值及流量对分离和测定的影响。选择草酸-均苯四酸二元混合液作淋洗液,采用非梯度淋洗方式;确定选择了最佳显色剂流量和检测波长。在最佳色谱条件下,建立了线性回归方程,检出限为0.2 mg/L,相对标准偏差≤3.7%,回收率为97.2%~106.7%。本方法已用于黄金中Y含量的测定。     

钨精矿中钡、锶含量的连续测定

研究了火焰原子吸收光谱仪连续测定钨精矿中钡、锶含量的方法。试样经碳酸钠—过氧化钠熔融,熔融物用硝酸溶液提取,在仪器最佳工作条件下,快速、准确地连续测定钨精矿中钡、锶含量。实验表明该方法操作简便,灵敏度高,干扰少,钡的回收率为94.2%～96.3%;锶的回收率为94.0%～102.5%。     

EDTA滴定法测定镁-锌-钇三元合金成分

研究了采用EDTA络合滴定法连续快速测定镁-锌-钇三元合金中各主体成分的方法。控制溶液pH值为5.0~5.5,先以EDTA滴定镁-锌-钇三元合金中的锌钇合量,再在pH值为9.0~9.4时,通过氨水沉淀分离钇后滴定锌的含量,滴定时加入三乙醇铵掩蔽主要干扰元素铁。采用所确定的分析方法对多种组分的三元合金样品进行测定,Zn∶Y∶Mg=3∶1∶96时RSD小于3%,Zn∶Y∶Mg=6∶3∶91时RSD小于2%,标准加入回收率在98%~100%范围内。     

钢中微量锶的极谱法测定

钢中微量锶的测定,现有的方法是采用偶氮胂Ⅲ光度法,本文选择了四甲基碘化铵为支持电解质,示波极谱法测定较低浓度的锶,并应用于钢中微量锶的分析,取得了较好的效果。峰值电位:Ep=-2.15V(vs.SCE)。其检出限量为:0.5μg/ml,适用于测定钢中0.005～1％锶。     

电感耦合等离子体质谱法测定钇铁合金中14种稀土杂质

采用硝酸-双氧水处理钇铁合金样品,以0.3mol/L硝酸为测定介质,选用¹⁰³Rh和¹⁸⁵Re作为内标元素对基体效应和测量信号进行补偿和校正,实现了电感耦合等离子体质谱法(ICP-MS)对钇铁合金中14种稀土杂质元素的测定。通过选择合适的同位素和干扰校正方程消除了质谱干扰;通过选择稀释因子为2000,即控制基体质量浓度为0.5mg/mL进行测定消除了基体效应的影响。在优化的实验条件下,14种稀土元素的校准曲线线性相关系数都在0.9999以上,各元素的检出限为0.003~0.020μg/L。将实验方法应用于钇铁合金样品中稀土杂质的测定,测定结果的相对标准偏差(RSD,n=11)介于0.97%~6.5%之间,加标回收率为96%~104%。采用实验方法对钇铁合金样品进行测定,同时采用基体匹配结合电感耦合等离子体原子发射光谱法(ICP-AES)进行方法对照试验,两种方法测定结果基本一致。     

90m~2烧结机机头电除尘器改造

唐山不锈钢有限责任公司3台90 m2烧结机机头100 m2单室三电场电除尘器存在烟气收集率低、系统漏风严重、现场工作环境恶劣等问题,在对原有100 m2单室三电场除尘设施进行修缮后,增设了第4电场,第4电场采用移动电极技术。同时,更换了除尘管道,对烟罩进行加固。改造后,除尘器的除尘净化效率提高,净化后外排烟含粉尘≤50 mg/m3,优于国家现行排放标准。     

惰气熔融-红外吸收法测定药芯焊丝药粉中高含量氧

研究了惰气熔融-红外吸收法测定药芯焊丝药粉中高含量氧的可行性,确立了氧氮氢分析仪的最佳工作条件。结果表明:在分析功率为5.5 kW,称样量为20~60 mg,加入0.3~0.5 g纯铁做助熔剂的条件下,以重铬酸钾校准仪器,选用手动投样-间歇加热模式,可以得到满意的分析结果。方法应用于药芯焊丝药粉实际样品中氧的测定,结果与差减法测得值基本一致,相对标准偏差(n=5~7)小于5.5%,加标回收率为90%~103%。     

Analysis of reduction of iron ore and oxidation of reducing gas in moving bed

To investigate the influence of technical parameters on reduction of iron ore and oxidation of reducing gas in moving bed, the coupling kinetic model of iron oxide reduction and reducing gas oxidation in moving bed was established. The model was applied in pre- reduction shaft furnace of C- 3000, and main calculating results were in a good accordance with production data. At a certain ratio of gas flow to ore mass, improving gas velocity at standard state can increase output of metal iron, yet decrease ratio of metallization and gas utilization rate. At a certain gas velocity at standard state, improving ratio of gas flow to ore mass can increase ratio of metallization, yet decrease output of metal iron and gas utilization rate. Reduction potential of gas has a substantial effect on reduction efficiency. It is suggested to improve reduction potential of gas to a 95% level for a high ratio of metallization. At a certain gas velocity at standard state, increasing gas pressure can improve ratio of metallization and gas utilization rate. Inert gas content has a disadvantageous effect on reduction reaction in moving bed. It is advantageous for improving reduction efficiency in moving bed by adjusting increasing ratio of pellet or adding part of rich- hydrogen gas in reducing gas.     

基于无标样分析软件的X射线荧光光谱法测定金刚石刀头成分

金刚石刀头的成分分析,对于改进生产配方,提高金刚石刀头的切割效率和切割寿命具有重要意义.对于不同的切割对象,需要不同性能的金刚石刀头,从而导致金刚石刀头成分复杂多变,再加上缺乏标样等因素,研究报道相对较少.实验利用X射线荧光光谱法(XRF)的无标样半定量软件对金刚石刀头中的骨架元素Fe、Cu、Zn、Sn进行检测,解决了...     

Laparoscopic cholecystectomy

Traditional cholecystectomy has been the standard surgical treatment of the gallstone disease for more than 100 years. The technical development led to a new surgical procedure and its rapid acceptance. This is laparoscopic cholecystectomy. Its application is becoming widespread in therapy too. But most of the surgeons are lack of technical experiences in this field. Currently it restricts the indications those are anyway the same of standard cholecystectomy. Besides its many advantages, laparoscopic cholecystectomy has its own disadvantages and being an invasive procedure, there are possibilities of complications. The latest can be reduced by the adequate choice of patients, the careful learning of the operative technic and by turning to open surgery (conversion) when it is necessary. Its morbidity is nearly equal to complications of standard cholecystectomy, but mortality rate is lower (0.05-0.2%). Our morbidity of performed 300 laparoscopic cholecystectomies was 6.4%. We had no death. The hospitalization became as short as 4 days. Our early clinical results (90%) are the same of traditional cholecystectomy. Laparoscopic cholecystectomy as a new surgical procedure involves the efficiency of the standard cholecystectomy and the noninvasive endoscopic technic. Laparoscopic cholecystectomy performed by well trained surgeons is a safe surgical procedure, its early results are excellent and makes the choice of surgical treatment, used in bile surgery richer.     

Photosonolysis of TCA, TCE, and PCE in Flow-Through Reactor System

Photosonolysis of 1,1,1-trichloroethane (TCA), trichloroethylene (TCE), and tetrachloroethylene (PCE) in water was investigated using a cup-horn, flow-through reactor system. Water containing titanium dioxide was deliberately contaminated with a mixture of volatile organic compound (VOC)—TCA, TCE, and PCE—and individual VOC. These solutions were irradiated with ultraviolet light (UV) and ultrasonic waves (US), independently and concurrently (UVUS). The values of the first-order degradation rate constant and the removal efficiency for the VOC were evaluated for the UV, US, and UVUS treatments. The results showed that the concurrent use of UV and US increased the VOC degradation rate and removal efficiency beyond the additive effect of UV and US, suggesting that the UVUS effect on the decomposition of the VOC is synergistic under certain conditions. TCE and PCE were more readily degraded than TCA, suggesting that double-bond cleavage is one of the initial degradation pathways. With the reactor specifications used, the photosonolysis process can produce water meeting the drinking water standard (MCLs of 5 μg∕L) for TCE and PCE with a removal efficiency of approximately 90%.     

管式炉燃烧-红外吸收法测定煤焦油中硫含量

采用管式炉燃烧-红外吸收法对煤焦油中硫含量的测定进行了研究。在研究炉膛温度、延迟时间、比较水平和称样量等对硫含量测定影响的基础上,优化了工作参数。当炉膛温度为900 ℃,延迟时间为30 s,比较水平为1.0,称样量为0.100～0.200 g之间时,硫的测定范围在0.005%～4%（质量分数）之间,校准曲线的相关系数大于0.9,RSD小于3%。本实验方法与国标GB387-90空气流-管式炉燃烧-亚硫酸-氢氧化钠滴定法对比,测定结果基本一致。     

氯铂酸铵酸洗除杂精炼铂

提出通过酸洗氯铂酸铵除杂精炼铂的方法。研究了酸种类、酸浓度、固液比、温度对酸洗除杂效率的影响,优选条件下90%以上的Na、Al、Fe、Si被去除,铂溶解率低于0.3%,酸洗氯铂酸铵制备的海绵铂除Sn外其余杂质含量达到SM-Pt 99.95标准。对酸洗过程Sn的行为研究结果表明,酸洗或煅烧氯铂酸铵都可以去除以(NH₄)₂SnCl₆形式存在的Sn,实现相同的除Sn效果,但不能去除以SnO₂形式存在的Sn。     

Spectrophotometric determination of plasma thiocyanate by formation of an ion-pair with methylene blue

We describe a sensitive method for measuring thiocyanate in 500 microliters plasma samples. This technique, although slower than the standard method, improves sensitivity. It requires the extraction in chloroform of an ion-pair formed between thiocyanate ions and methylene blue in acidic medium. Within-day precision had a coefficient of variation of 2.5% and between-day precision a CV of 4.75%. The results were well-correlated (r = 0.997). For 30 non-smokers, the mean thiocyanate level was < 55 mumol/l, and for 30 smokers 90 mumol/l (SD = 20). The method was successfully applied to seven fire smoke victims treated with hydroxocobalamin.