黄金精炼工艺综述与展望

针对黄金精炼的主要工艺进行了分析,列举了各种工艺的优缺点及适用情况。其中主要分析了黄金萃取工艺和黄金电解工艺,简要分析了控电位氯化工艺,王水还原工艺及氯化挥发工艺。同时结合作者自身工作经验对黄金精炼的主要工艺进行了展望。     

高磁感取向硅钢中的抑制剂

结合高磁感取向硅钢的生产工艺和技术发展趋势,对板坯高温、中温和低温加热工艺中的抑制剂进行了论述和分析。MnS和AlN是高温加热工艺的主要抑制剂。对于中温加热工艺则主要利用AlN为主要抑制剂,Cu2S和MnS作为辅助抑制剂。低温板坯加热工艺中所采用的抑制剂主要为AlN,其工艺手段就是在发生二次再结晶之前进行渗氮处理。Nb(C,N)有可能成为低温板坯加热工艺一种新型抑制剂。     

铜熔炼渣缓冷工艺管理及改进

铜冶炼厂广泛采用渣缓冷工艺回收炉渣中的铜,该工艺可以提高铜的回收率,增加企业的经济效益。文章介绍了铜熔炼渣的缓冷工艺和主要设施,讨论了渣缓冷工艺存在的主要问题并提出了解决措施,为铜熔炼渣缓冷工艺的生产管理提供参考。     

黄金精炼工艺研究

"优质、低耗、环保"是当前对黄金精炼工艺的总体要求,本文总结了主要的黄金精炼工艺,分别介绍了主要黄金精炼工艺的原理、发展起源,综合分析其优缺点。对黄金精炼工艺的工程化应用和技术发展有着重要意义,同时也指出了黄金精炼工艺未来发展的方向。     

转炉冶炼—连铸—高速轧制工艺生产冷镦钢盘条

阐述了冷镦钢的涵义、工艺特点,介绍了江苏永钢集团有限公司采用转炉冶炼—连铸—高速线材轧制工艺生产冷镦钢盘条的主要技术措施及工艺特点,提出了提高冷镦钢质量的主要途径.     

浅谈铜冶炼渣缓冷工艺

介绍了铜冶炼生产过程中熔炼渣的缓冷工艺及主要配套设施,对缓冷原理和主要工艺参数的选取进行了详细论述,为铜冶炼渣缓冷工艺的选择和设计提供参考.     

红土镍矿回转窑焙烧-预还原工艺简述

主要介绍了回转窑焙烧-预还原工艺过程、主要红土镍矿冶炼厂回转窑工艺参数,分析了回转窑工艺特点、存在问题及改进措施。     

真空碳酸钾法焦炉煤气脱硫工艺优化与创新

介绍了真空碳酸钾煤气脱硫工艺的工艺原理、工艺流程、主要工艺控制指标、工艺特点等,分析了该工艺在运行过程中存在的一些问题,为解决这些问题进行了工艺优化与创新。     

炼铁工艺的新发展和炼铁工序的结构优化

炼铁工艺主要有高炉工艺、直接还原和熔融还原工艺，正在研究开发的还有碳化铁工艺。这些工艺中，高炉工艺是我国主要的炼铁工艺，因此，我国炼铁工序优化的重点是高炉炼铁工艺的优化。高炉工艺优化的目标是提高质量，降低成本，改善环保。     

钒钛磁铁矿提钒工艺发展历程及趋势

介绍了钒钛磁铁矿提钒工艺的发展历程及工艺现状,阐述了各种提钒工艺的优点、缺点、主要工艺参数和技术指标,针对现有提钒工艺的不足,指出了下一步提钒工艺的研究方向.     

Selenium content of Brazil nuts from two geographic locations in Brazil

Brazil nuts (Bertholletia excelsa) natively contain very high concentrations of selenium. Since dietary selenium, including Brazil nuts, have been associated with protection against tumor development in laboratory animal studies, it was of interest to determine the selenium content of the nuts from different nut-growing regions of Brazil. In the work reported, 162 nuts from each of two regions (Acre-Rondonia and Manaus-Belem) were individually analyzed for selenium. The average +/- standard deviation and range of selenium concentrations in ppm, fresh weight for nuts from Acre-Rondonia and Manaus-Belem regions were, respectively, 3.06 +/- 4.01 (0.03-31.7) and 36.0 +/- 50.0 (1.25-512.0). The toxicology of Brazil nut consumption is discussed.     

从含硒废料中回收制备高纯硒

介绍从含硒废料回收制备高纯硒的工艺过程,首先采用氧气燃烧法将废料氧化为各自的氧化物,然后于溶剂中分离、升华提纯、再还原处理纯净含硒溶液,制备出的硒粉,采用ICP-AES法对其中杂质元素进行测定,硒粉纯度达到5N(99.999%)。     

硫酸冒烟-碘量法测定湿法冶金泥、渣等富硒物料中铜含量

采用王水-氢氟酸溶解样品,加硫酸高温冒烟挥发除去硒,建立了碘量法测定冶金泥、渣等富硒物料中铜的方法。实验表明,在冰醋酸介质中采用碘量法测定铜时,硒也可发生碘量反应从而干扰铜的测定;采用王水-氢氟酸处理样品后,硒的残留量超过了测定铜时硒的最大允许量,而再经硫酸高温冒烟挥发法处理后,硒几乎无残留,可消除硒对测定铜的干扰。确定了挥发法除硒的最佳硫酸用量为3 mL;对挥发除硒的机理进行了探讨。采用本方法测定铜阳极泥1^#、铜阳极泥2^#、酸泥、铁置换渣和富硒渣样品中2%～35%范围内的铜,所得结果与国标法GB/T3884.1-2000一致,相对标准偏差（RSD, n=6）均小于4%。     

The behavior of selenium and tellurium in metal-matte systems

The distribution of selenium and tellurium between molten metal and matte was determined at temperatures of 1100° to 1250°C. The experimental technique permitted separate sampling of each phase while at temperature. Partition coefficients (ratio of weight percent selenium or tellurium in the matte to weight percent selenium or tellurium in the metal) varied from 10.5 to 16.9 for selenium and 5.5 to 8.1 for tellurium. The coefficients decreased with increasing temperature but were essentially independent of impurity concentration, iron content and oxygen and SO₂ partial pressures over the ranges studied. Application of these results to actual operations is discussed. The similarities in the chemical behavior of S, Se, and Te during smelting are also considered.     

Lessons from basic research in selenium and cancer prevention

The article reviews the progress in basic research of selenium and cancer prevention during the past decade. Special emphasis is placed on the following four major areas of discussion: 1) chemical forms of selenium and anticarcinogenic activity; 2) selenium-enriched food; 3) in vitro effects of selenite vs. monomethylated selenium; and 4) aromatic selenium compounds. It is clear that basic research has contributed new knowledge to our understanding of selenium biochemistry, anticancer efficacy and regulation of cell growth. Some of this information could be ready for incorporation into the design of a second-generation selenium trial in humans.     

Effect of selenium and mercury on survival of chick embryos

Factorial experiments were arranged in a completely randomized or randomized block design. The factors included: selenium and day of injection; mercury and day of injection; selenium and mercury; and selenium, mercury and day of injection. Each treatment factor consisted of several levels, selenium ranged from 0.00 p.p.m. to 0.05 p.p.m., mercury from 0.00 p.p.m. to 0.30 p.p.m. and injection was performed on day-3, 9, and 15 of incubation. Babcock-300, and White Leghorn x New Hampshire cross eggs were obtained from 13-15 month old hens. Mercury was injected into the air cell at 4 or 24 hours after selenium injection. Analysis of variance on arcsine transformed data showed that selenium significantly decreased survival at all 3 injection times (P less than 0.01). Survival was significantly greater with increasing age at injection (P less than 0.01). Survival of embryos significantly decreased (P less than 0.01) with increasing levels of mercury from 0.00 p.p.m. to 0.20 p.p.m. injected into eggs on day-3 of incubation. Survival of embryos injected at later stages was less than that of controls but not significantly less. Injection of low levels of selenium, 0.01 p.p.m. or 0.02 p.p.m., to mercury treated eggs tended to improve the survival of embryos as compared to treatment with mercury alone, although individual differences were not significant. At higher levels, selenium accentuated the toxicity of mercury.     

The kinetics of selenium removal from molten copper by powder injection

Chemical thermodynamic calculations show that selenium removal from copper melts using sodium carbonate (soda ash) is only effective under reducing conditions. Reducing conditions can be generated by carbon, but even more effectively by calcium carbide which has not been used previously for such a purpose. To clarify the kinetics of these multiphase, multicomponent reactions, various mixtures were either placed on top of or injected into 70 kg heats of molten copper. The following reagents were found to be effective in removing selenium: soda ash-graphite mixtures, calcium carbide, and calcium carbide-soda ash mixtures, in increasing order of effectiveness. Experiments were also performed with synthetic blister copper containing oxygen, selenium, tellurium, bismuth, nickel, silver, and lead. As expected from the thermodynamic analysis, only the first three of these elements were removed. A mathematical model was developed to describe the diffusion-controlled reaction kinetics of selenium and oxygen removal at calcium carbide particle interfaces. Very good agreement between the model and experiments was achieved for the reaction paths of selenium and oxygen when 35 pct of the particles were in contact with the melt. The utilization of powder varied over a wide range (0 to 10 pct), depending on the selenium and oxygen contents. The industrial implications of this work are discussed in terms of multielement removal, refractory erosion, temperature loss, and reagent utilization.     

气相色谱-质谱联用技术在砷、硒、汞和铅形态分析中的应用

气相色谱-质谱联用技术具有分析速度快、灵敏、准确的优点,其在元素形态分析中的应用越来越广泛。本文对气相色谱-质谱联用技术（GC-MS）的接口设计方法做一简要回顾。并介绍了砷、硒、汞和铅的存在形式及其形态分析的意义,综述了气相色谱与质谱联用技术在砷、硒、汞和铅四种元素的形态分析中的应用情况。展望了该联用技术的发展趋势,及其局限性。     

Selenium deficiency favors the appearance of heart failure after multiple injury

A 47-year-old multiple trauma patient, experiencing a C. Difficile colitis with diarrhoea, developed diffuse oedema with peritoneal and pleural effusion due to global heart failure. Selenium deficiency, reported in trauma patients, may explain the occurrence of cardiomyopathy. The role of selenium in cardiac dysfunction and the various situations inducing a selenium deficiency are discussed.     

Study of prediagnostic selenium level in toenails and the risk of advanced prostate cancer

BACKGROUND: In a recent randomized intervention trial, the risk of prostate cancer for men receiving a daily supplement of 200 microg selenium was one third of that for men receiving placebo. By use of a nested case-control design within a prospective study, i.e., the Health Professionals Follow-Up Study, we investigated the association between risk of prostate cancer and prediagnostic level of selenium in toenails, a measure of long-term selenium intake. METHODS: In 1986, 51,529 male health professionals aged 40-75 years responded to a mailed questionnaire to form the prospective study. In 1987, 33,737 cohort members provided toenail clippings. In 1988, 1990, 1992, and 1994, follow-up questionnaires were mailed. From 1989 through 1994, 181 new cases of advanced prostate cancer were reported. Case and control subjects were matched by age, smoking status, and month of toenail return. Selenium levels were determined by neutron activation. All P values are two-sided. RESULTS: The selenium level in toenails varied substantially among men, with quintile medians ranging from 0.66 to 1.14 microg/g for control subjects. When matched case-control data were analyzed, higher selenium levels were associated with a reduced risk of advanced prostate cancer (odds ratio [OR] for comparison of highest to lowest quintile = 0.49; 95% confidence interval [CI] = 0.25-0.96; P for trend = .11). After additionally controlling for family history of prostate cancer, body mass index, calcium intake, lycopene intake, saturated fat intake, vasectomy, and geographical region, the OR was 0.35 (95% CI = 0.16-0.78; P for trend = .03). CONCLUSIONS: Our results support earlier findings that higher selenium intakes may reduce the risk of prostate cancer. Further prospective studies and randomized trials of this relationship should be conducted.