大阪精炼厂从铜电解阳极泥中回收硒

自从1927年大阪精炼厂开始生产硒以来,其产量随着铜阳极泥处理量的增加而增加,目前的生产能力约18吨/月。该厂处理阳极泥的特点是用一台短回转窑进行氧化焙烧,以亚硒酸钠溶液形式回收硒。     

硒化亚铜浊度法直接测定微量硒

本文系统研究了用硒化亚铜浊度法直接测定硒的条件.经电解锰中硒和铅矿中微量硒实样测定表明,本法结果与极谱法及其它方法结果一致.本法快速简便,可测0.01mgSe.一、试剂硒标准溶液;20μg/ml;柠檬酸铵:30%;铜溶液;500μg/ml;聚乙烯醇:0.2%;抗坏血酸:1%;无硒锰溶液:50mg/ml.二、操作手续     

蒸硒渣处理过程的优化研究

通过水浸分铜、控电位氯化氧化分金、亚钠沉金、锌粉置换等试验,确定了蒸硒渣新的处理工艺流程图。水浸分铜工序最佳条件:添加6%的NaCl,水浸分铜反应主要是扩散反应控制。控电位氯化氧化分金工序最佳条件:以酸度为1 mol/L,NaCl加入量为20%、液固比5∶1、NaClO_3加入量4%,80℃下反应2 h,终点氧还原电位在1 100 mV左右。亚钠沉金时金的还原率为95%以上,沉金后液中金含量100 mg/L,其它元素基本不被还原。锌粉置换时,置换后液中铂与钯含量均小于1 mg/L。与现有工艺流程相比,新的工艺流程方案处理1 t蒸硒渣可增加2 000元的经济效益。     

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%。     

原子荧光光谱法测定低硒电解锰中微量硒

建立氢化物发生-原子荧光光谱法测定低硒电解锰中微量硒的快速、准确的检测方法,促进低硒电解锰的出口。运用条件试验,精密度实验及回收率测定对氢化物发生-原子荧光光谱法测定低硒电解锰中微量硒进行试验和研究。Se含量在0～200μg∥L范围内线性关系良好,相关系数为0．9996,检出限为0．010μg／L;在0．02～0．1mg／kg添加浓度范围内,平均回收率在93．2％～90％之间;相对标准偏差为1．96％～2．77％。结果表明该方法灵敏度高,检出限低,精密度和准确度高,操作简捷,安全环保,可广泛应用于低硒电解锰中微量硒的测定。     

重量法测定铜铟镓硒靶材中硒

采用硝酸和盐酸低温加热溶解铜铟镓硒靶材样品,以将样品中的硒氧化为亚硒酸(H2SeO3),在水浴或低温下用尿素驱除硝酸,然后以盐酸为介质,采用亚硫酸将亚硒酸还原为单质硒沉淀,实现了硒与样品中其他元素的分离,将沉淀经抽滤烘干称重,通过计算得到靶材中硒含量,据此建立了重量法测定铜铟镓硒靶材中硒含量的方法。实验确立了测定的最佳条件,并进行了共存元素的干扰试验。结果表明,铜铟镓硒靶材中的铜、铟、镓对硒的测定无影响。采用实验方法测定铜铟镓硒靶材内控样品,测定值与理论配制值基本一致,相对标准偏差(RSD,n=11)在0.050%~0.48%之间。3家不同实验室结果平均值的最大误差不超过0.20%,相对标准偏差均小于0.50%。回收率试验表明硒的回收率在99%~101%之间。     

用氢氧化钠从银渣中浸出硒碲试验研究

银渣主要含银、硒及少量铁、铜、铋、锑、碲、铅等,硒以亚硒酸银形式存在。研究了用氢氧化钠从银渣中选择性浸出硒、碲,考察了浸出时间、反应温度、液固体积质量比、氢氧化钠浓度对硒、碲浸出率的影响。试验结果表明:氢氧化钠浓度和液固体积质量比对硒、碲浸出率影响较大,硒和部分碲被浸出,其他元素如银、铜、铁等及部分碲留在渣中,浸出过程具有选择性;在反应温度95℃、液固体积质量比4∶1、氢氧化钠初始质量浓度200g/L、搅拌速度250r/min条件下浸出4h,硒、碲浸出率分别为97.22%和36.75%。此外,也研究了用硝酸浸出碱浸渣中的银。浸出渣衍射分析结果表明,渣中残留的硒主要以亚硒酸钠形式存在,需要用氢氧化钠再次浸出。     

硒和碲

硒是一种稀有元素,在地壳中的平均含量约为0.09ppm,不如银(0.1ppm)丰富。没有一种有用矿石的含硒量在经济上具有重大意义,因此,大部分原生硒都是从电解精炼阳极泥中回收贵金属时的副产品。阳极泥含硒1～55%。     

云铜科技研制出99.99966%高纯硒

<正>近日,云南铜业科技发展股份有限公司(以下简称"云铜科技")5N硒项目团队研制出纯度为99. 999 66%的高纯硒,且得到外部送检单位的核验,这标志着云铜科技在硒的高纯化上实现了重大突破。硒是人体生命活动中必须的微量元素之一,是人体的抗氧化剂,能提高人体免疫力,具有辅助防癌抗癌、降低血脂血压、防止肝脏病毒疾病等多种生物功能。98%的硒制成二氧化硒,主要用于电解锰等领域,99. 9%以上的硒多用于光伏、铜铟镓硒等复合材料。随着硒产品越来越丰富,比如富硒大米、富硒     

四川省万源市土壤硒形态特征及影响因素分析

硒是人体和动物体内的必需微量元素.适量硒对人体健康有重要的作用,硒的形态对硒的吸收效果具有重要的影响.四川省万源市是重要的富硒地区之一,对万源市不同区域土壤硒及其形态进行分析,详细分析了土壤中硒的形态特征,并对硒形态的影响因素进行了探讨,以便为今后开发硒产品提供依据.结果表明,万源市土壤中硒各形态的量和所占全量的比例均为残渣态>有机态>酸溶态>交换态>水溶态,有效态所占比例超过1O%,部分在20%以上;不同片区土壤硒的含量和形态特征有所不同,总体上大竹河片区土壤硒的总量和有效态高于其他片区;pH值的大小与水溶态、交换态和残渣态的关系较为明显.与酸溶态的关系次之.与有机态的关系最差:除水溶态外,土壤各形态硒与土壤总硒具有较好的相关性.     

Lithium exerts a time-dependent and tissue-selective attenuation of the dexamethasone-induced polyamine response in rat brain and liver

Recently El-Bayoumy and coworkers have reported that 1,4-phenylene-bis(methylene)selenocyanate (p-XSC) was very effective in inhibiting 7,12-dimethylbenz(a)anthracene (DMBA)-induced mammary carcinogenesis and adduct formation during the initiation phase (Cancer Res., 52, 2402-2407, 1992). Furthermore, this compound was found to be well tolerated by rats at high doses. The present study was designed to extend these earlier observations by investigating the response to lower levels of p-XSC given either before or after DMBA administration. At a level of 15 p.p.m. Se, p-XSC suppressed total mammary tumor yield by 80% and 52% in the initiation phase and post-initiation phase, respectively. A dose-response effect was evident in the range 5-15 p.p.m. Se. When p-XSC was given at a level of 5 p.p.m. Se during the entire course of the experimental period, total tumor yield was reduced by half. This dose is about 4 x less than the maximum tolerable dose (MTD). Other selenocyanate analogs were also examined in an attempt to obtain information on their respective chemopreventive index, which is calculated as the ratio of MTD to the effective dose which produces approximately a 50% inhibition in total tumor yield (ED50). The reagents studied included potassium selenocyanate, methyl selenocyanate and benzyl selenocyanate, as well as sodium selenite (reference compound). Compared to p-XSC, which has a chemopreventive index of 4.0, the other four compounds have a lower index ranging from 1.3 for sodium selenite and potassium selenocyanate to 2.0 for methyl selenocyanate and 2.5 for benzyl selenocyanate. A high chemopreventive index signifies that a compound is well tolerated at doses required for cancer suppression. The last component of the present study involved the repletion assay of liver glutathione peroxidase in selenium-deficient rats as a biomarker to estimate the metabolizability of the above selenium compounds. The bioavailability data suggest that the selenium from p-XSC is not as efficiently incorporated into glutathione peroxidase as the selenium from selenite or the other selenocyanate analogs. Currently, we are working under the hypothesis that the chemical structure of the RSeCN compound could affect activity per se and also influence the rate of release of selenium from the parent compound, thereby impacting on the anticarcinogenic efficacy, tolerance and bioavailability of the compound.     

The effects of selenium deficiency, dietary selenium, and vitamin E supplementation on the oxidative status of pig liver

The aim of this work was to determine the effect of selenium (Se) deficiency on the porcine liver oxidative stability and to investigate Se content and oxidative status in porcine liver after dietary supplementation with vitamin E (vit E), sodium selenite, and selenized yeast. Experimental animals were fed a basal corn meal, low in Se and vit E, for a 4-week depletion period before being given the experimental diets containing different levels of Se and/or vit E for 5 months. Dietary treatments were the basal diet with no additions (control); the basal diet supplemented with 25 mg of vit E/kg of feed (group I); basal diet + 0.3 mg selenite-Se/kg (group II); basal diet + 0.3 mg selenized yeast-Se/kg (group III); basal diet + 0.1 mg selenite-Se + 10 mg vit E/kg (group IV); and basal diet + 0.3 mg selenite-Se + 25 mg vit E/kg (group V). The Se content in pig liver samples was 33 to 192% lower in the control group than in all the other groups. Dietary Se from selenized yeast had a more pronounced effect on Se level than dietary sodium selenite. The highest Se content was found in liver samples from the Se + vit E supplemented group (group V). All the dietary supplementation schemes significantly improved the oxidative status of porcine liver compared with the control group samples. The best results were obtained by simultaneous dietary supplementation with Se + vit E (groups IV and V) > group III > group II > group I.     

Bioavailability of selenium accumulated by selenite-reducing bacteria

The bioavailability of selenium (Se) was determined in bacterial strains that reduce selenite to red elemental Se (SeO). A laboratory strain of Bacillus subtilis and a bacterial rod isolated from soil in the vicinity of the Kesterson Reservoir, San Joaquin Valley, CA, (Microbacterium arborescens) were cultured in the presence of 1 mM sodium selenite (Na2SeO3). After harvest, the washed, lyophilized B. Subtilis and M. arborescens samples contained 2.62 and 4.23% total Se, respectively, which was shown to consist, within error, entirely of SeO. These preparations were fed to chicks as supplements to a low-Se, vitamin E-free diet. Three experiments showed that the Se in both bacteria had bioavailabilities of approx 2% that of selenite. A fourth experiment revealed that gray SeO had a bioavailability of 2% of selenite, but that the bioavailability of red SeO depended on the way it was prepared (by reduction of selenite). When glutathione was the reductant, bioavailability resembled that of gray SeO and bacterial Se; when ascorbate was the reductant, bioavailability was twice that level (3-4%). These findings suggest that aerobic bacteria such as B. subtilis and M. arborescens may be useful for the bioremediation of Se-contaminated sites, i.e., by converting selenite to a form of Se with very low bioavailability.     

Selenite and selenium yeast as feed supplements for dairy cows

The availability of inorganic and organic forms of selenium to dairy cows was studied by giving 25 cows supplementary selenium for 9 months either as sodium selenite or as a selenium-containing yeast product. Group I (eight cows) received 3.0 mg selenium as sodium selenite daily, group II (nine cows) received 3.0 mg selenium as the selenium yeast product, and group III (eight cows) received 0.75 mg selenium as the selenium yeast product. The total selenium contents of the ration were 0.26-0.32 mg/kg feed dry matter for groups I and II, and 0.16-0.18 mg/kg for group III. The supplement of 0.75 mg selenium daily from the yeast product maintained the selenium concentrations of whole blood and milk at the same levels as 3.0 mg selenium as sodium selenite, and 3.0 mg selenium from the yeast product increased the selenium concentration of whole blood by approximately equal to 40% and that of milk by approximately equal to 100%. The activity of glutathione peroxidase in erythrocytes of the group given selenite was not significantly different from that in either of the groups given the yeast product. The concentrations of selenium in the tissues of two cows from each group were marginal to adequate, and there was a trend for the concentrations to be higher in the tissues of the cows supplemented with the yeast product.     

Human hepatocyte nuclear factor-4 (hHNF-4) gene maps to 20q12-q13.1 between PLCG1 and D20S17

Male Hartley guinea pigs (480-610 g; n=5) were treated intratracheally with saline, cadmium (Cd, 0.3 mg) as cadmium chloride, selenium (Se, 0.3 or 0.06 mg) as sodium selenite or Se (0.06 mg) and Cd (0.3 mg). After 24 hours, lungs were collected and analyzed for prostaglandin (PGE2), thromboxane (TXB2) and leukotriene (LTC4) levels. Results indicated that, 0.3 mg Se and 0.06 mg Se in combination with 0.3 mg Cd increased PGE2 significantly. Selenium and Cd alone or in combination, decreased LTC4 and TXB2 significantly.     

Selenium regulates gene expression for estrogen sulfotransferase and alpha 2U-globulin in rat liver

Dietary intake of the essential trace element selenium (Se) regulates expression of genes for selenoproteins and certain non-Se-containing proteins. However, these proteins do not account for all of Se's biological effects. The objective of this work was to identify additional genes whose expression is regulated by Se. Identification of these genes may reveal new functions for Se or define mechanisms for its biological effects. Weanling male Sprague-Dawley rats were fed a Torula yeast-based Se-deficient basal diet or the same diet supplemented with 0.5 mg Se/kg diet as sodium selenite for 13 weeks. Total RNA was used as template for RNA fingerprinting. Two differentially expressed cDNA fragments were identified and cloned. The first had 99% nucleotide identity with rat liver estrogen sulfotransferase (EST) isoform-6. The second had 99% nucleotide sequence identity with rat liver alpha 2u-globulin. The mRNA levels for both were markedly reduced in Se deficiency. Laser densitometry showed that EST mRNA in Se deficiency was 7.3% of that in Se-adequate rat liver. The level of alpha 2u-globulin mRNA in Se-deficient rat liver was only 12.6% of that in Se-adequate rat liver. These results indicate that dietary Se may play a role in steroid hormone metabolism in rat liver.     

Functional diversity and clonal frequencies of reactivity in the available antibody repertoire

Our objective was to determine the effect of level and chemical form of dietary selenium on productivity of beef cows, concentrations of triiodothyronine (T3), and thyroxine (T4) in plasma, and immunoglobulins (IgG and IgM) in plasma and colostrum of cows. Pregnant cows (n = 60) were randomly allocated among four dietary treatments of 20, 60, or 120 ppm Se as selenite and 60 ppm as selenomethionine from selenized yeast (SeY) in salts offered free-choice. Treatments began 90 d prepartum and continued through the second parturition. Treatments did not affect the final body weights of cows or birth weights or weaning weights of calves. At parturition, cows given salt with 20 ppm Se as selenite had lower (P < . 05) concentrations of Se in blood than cows with access to higher-Se salts. Treatments affected (P < .01) the concentration of T3 and the ratio of T3:T4 in plasma of cows. The concentration of T3 in plasma of cows with access to salt with 20 ppm Se was 14% lower than that in cows supplemented with 60 ppm Se as selenite or SeY. Plasma IgG in cows and calves, colostrum, and Se concentrations in colostrum, casein, and whey were lowest (P < .01) for cows given salt with only 20 ppm Se. Thus, salts with concentrations of 60 and 120 ppm Se improved measures of Se status in cows and calves. Consideration should be given to the concentrations of T3 and IgG when determining the nutritional requirements for Se in cattle.     

Selenium and vitamin E and incidence of retained placenta in parturient dairy cows. II. Prevention in commercial herds with prepartum treatment

In a series of field experiments in Ohio involving 193 parturient cows of the Holstein and Guernsey breeds, the prophylactic efficacy of selenium and vitamin E was tested under field conditions. Herds initially were chosen because of a chronic problem with retained placenta which could not be related to a known etiological factor. Each herd was divided into three groups. Group A received an injection of 50 mg of sodium selenite 40 days prepartum and 680 units of alpha tocopherol acetate followed by the same treatment 20 days prepartum. Group B received a single injection of 50 mg of sodium selenite 20 days prepartum, and 680 IU of vitamin E. Group C served as the control. Incidence of retained placenta was reduced from a mean of 51.2% in control cows to 8.8% for animals injected with selenium and vitamin E. No differences in efficacy were between Group A and B, and it appears that the single 20 day prepartum injection of 50 mg of sodium selenite and 680 IU of alpha tocopherol acetate is an effective prophylactic for prevention of retained placenta.     

Symmetrical cyanosis circumscripta e lipomate

In order to assess the Se status in individuals living in the Veneto region, a series of related measurements was performed. These included plasma selenium by PIXE and glutathione-peroxidase (GSH-Px) activities in plasma, red blood cells and platelets. Individuals were either normals or people suffering from various liver diseases. Moreover, an oral supplement of sodium selenite was given to 13 patients suffering from stable chronic renal failure (CRF) in parallel to 26 normals: data on plasma GSH-Px and on serum creatinine and creatinine clearance were collected either before or after supplementation. Results were in support of a relatively low selenium status: mean +/- SD plasma Se values of normals (0.82 +/- 0.17mumol/L, n = 82) were comparable to data observed in European regions where Se deficiency was already known. Even lower values were observed in those with liver diseases. Among enzyme activities, the distribution of the data of platelet GSH-Px was in further support of low Se status in the evaluated individuals. After Se supplementation, both normals and CRF patients showed a significant increase in the creatinine clearance, reflecting an improvement of the glomerular filtration rate. We suggest that more extensive surveys of the Se status should be carried out in Italy; moreover, Se supplementation may be advisable in individuals affected with moderate impairment of renal function.     

Pathology of experimentally induced chronic selenosis (alkali disease) in yearling cattle

Prolonged oral exposure of cattle to elevated dietary selenium (Se) in forage and seleniferous plants in seleniferous areas of the western United States is associated historically with 2 clinical syndromes: alkali disease and "blind staggers." The potential for Se-induced disease in cattle and other species is considerable in areas with seleniferous shales, Se-accumulating plants, arid climates, and alkaline soils. These 2 Se-associated conditions were defined in the 1930s and 1940s, and the nosology of blind staggers is questionable. Seventeen yearling steers fed 0.15, 0.28, and 0.8 mg Se/kg body weight as selenomethionine or selenite for 120 days were euthanized and examined postmortem. Significant lesions were confined to 4 steers in the medium- and high-dose selenomethionine group and to 1 steer in the high-dose selenite group. Grossly, dystrophic hoof lesions developed in 2 steers, 1 of which had extensive separation of horn from lamellar and coronary epidermis and also lost hair from the tail switch. Histologically, tubules in the stratum medium of hooves from these 5 steers were replaced by islands of parakeratotic cellular debris, separated by more normal hoof matrix. Two of the 5 steers also had hyperplasia, acanthosis, parakeratosis, and disorganized germinal epithelium of varying severity in hoof epithelium, particularly at the tips of epidermal lamellae. These changes may distinguish the hoof lesions of chronic selenosis from those of chronic laminitis in cattle, in which dermal (chorial) changes predominate. In skin from the distal part of the tail of the animal that lost its switch, most follicles were atrophic and devoid of hairshafts and displayed dyskeratosis and mild superficial follicular keratosis. No significant lesions developed in tissues other than integument. Autometallographic staining for catalytic Se bonds in various tissues, including skin, liver, and kidney, revealed no positive staining of hair shafts; the correlation between stain intensity and dose group was poor. These findings indicate that dietary exposure for 4 months to 0.28 and 0.8 mg Se/kg in the form of selenomethionine and to 0.8 mg Se/kg in the form of sodium selenite reproduces in some cattle mild (subclinical) to severe (clinical) forms of alkali disease. No significant neurological, renal, or hepatic lesions developed, supporting the contention that blind staggers is caused by factors other than excessive dietary selenium.