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1.
粗汞含有众多杂质金属,杂质多数以HgxMy,HgM化合物、合金状态溶于汞中,从而影响其在电解过程中的分离效果,利用杂质与汞形成的合金的化学特点和易氧化的特性,在特殊的电解条件下,杂质汞合金阳极氧化固态氧化物微粒与汞分离。实践表明汞阳极氧化法具有效果好、节省能源、减少废液对环境的污染等优点。以其代替汞阳极电解法,作为高纯汞、超纯汞制备过程中的前级提纯方法,能获得更好的效果与效益。  相似文献   

2.
高纯碲市场价格不断上涨,是因为适于高纯碲规模化生产的技术仍不成熟.真空蒸馏法、电解精炼法仅有少数企业在应用,化学方法则存在引进新的杂质或设备腐蚀等问题.因此,根据在二组分相图中,有纯组分与熔体共存区域的事实,发明了一种利用熔融结晶原理生产高纯碲的方法.将4N碲在470℃下熔融,再将熔体注入结晶器中,利用加热设备余热及熔体本身放热,使熔体缓慢冷却一定时间,再自然冷却至室温.对碲锭进行切割,先析出的85%的结晶体为产品.该方法所用设备仅为一台密闭加热电炉和石英玻璃坩埚及石墨结晶器,操作很简单.适用于规模化生产,无需其他化学试剂,无设备腐蚀、无环境污染等其他问题.通过调节熔融结晶次数、结晶截取比例、缓慢冷却时间,企业可根据市场需求对碲的纯度、产量进行控制.经过一次结晶,碲的质量分数≥99.999.该方法有较高的工业应用价值.  相似文献   

3.
采用真空定向凝固技术,在不同真空定向凝固条件下,对拉制锑掺杂的单晶后的埚底料进行提纯并得到铸锭.对不同生长条件下铸锭的生长形貌进行分析.同时,通过ICP-AES测定了铸锭纵向的杂质元素的分布.结果表明,杂质Sb从底端到中上端由于定向凝固的作用呈现浓度升高,从中上端到顶端由于真空蒸馏的作用呈现浓度降低.  相似文献   

4.
真空蒸馏加剂除铅制备高纯铋   总被引:1,自引:0,他引:1  
从理论上分析了用真空蒸馏分离精铋中各杂质和通过加硫、加氯除铅的可行性.在真空炉内进行了精铋加剂除铅的实验研究,考察了加剂量、蒸馏温度、残压和蒸馏时间等4个因素对除铅的影响,得到了最佳工艺条件:加硫除铅,蒸馏温度控制在1 073 K,每克精铋加硫0.02 g,可将含铅3.0×10-5的精铋中的铅降到2.1×10-7,脱铅率约为99.3%;氯化除铅,蒸馏温度控制在1 023 K,每克精铋加氯化铜0.06 g,可将含铅3.0×10-5的精铋中的铅的含量降到2.4×10-7,脱铅率约为99.2%.精铋中的其他杂质也可在一定条件下通过真空蒸馏有效除去,均达到“99.999%”高纯铋的要求.  相似文献   

5.
高纯丙烯酸是生产高吸水性树脂(SAP)、水处理剂等高档丙烯酸下游产品的重要原料.由粗丙烯酸提纯生产高纯丙烯酸由于体系中醛类杂质沸点与丙烯酸接近,难以通过常规的精馏方法除去.本论述针对目前国内外高纯丙烯酸生产工艺,分别介绍了化学提纯法和近年来受到工业界与科技界越来越多关注的分级结晶技术在高纯丙烯酸生产中的工艺流程及其应用与研究进展,并对分级结晶技术中降膜结晶法进行了详细介绍,对两种方法各自特点进行多角度对比.分级结晶技术作为高效、低能耗、低污染的分离手段,面对国内丙烯酸产能的迅速发展,其必将成为高纯丙烯酸生产工艺的主流趋势.  相似文献   

6.
3N碲还原熔炼-扒渣提纯法制备4N碲   总被引:1,自引:0,他引:1  
为了满足碲的高端应用,开展了以3N纯度(即质量分数为99.9%)粗碲为原料,制备4N碲的工艺条件和中试研究,并采用等离子光谱仪(ICP)对样品进行了测试分析,确定了一种3N碲还原熔炼-扒渣提纯法制备4N碲的工艺方法:将1 %的还原剂与50目(300 μm)3N粗碲混匀,在700℃下还原焙烧1 h;加入0.4%的造渣剂,搅拌造渣15 min;粗碲杂质元素与造渣剂结合形成上浮渣,多次刮除至再无浮渣产生;将除渣后的碲熔浆倾入石墨模中铸锭,得到碲锭产品.该产品碲的质量分数≥99.998%,杂质元素总的质量分数<15×10-6,每种杂质元素的质量分数<5×10-6,完全符合4N纯度精碲要求.中试结果表明,该工艺流程简单,工艺周期短,成本低廉,环境污染小,是一种可规模化生产4N碲的新工艺.  相似文献   

7.
本文阐述了我国高铝矾土资源及其特点,指出高铝矾土选矿提纯是解决我国高纯优质高铝原料的唯一有效途径。文中介绍了各种提纯途径的试验结果,提出应根据高铝矾土中杂质种类、含量及嵌布粒度而采用不同的途径进行提纯。  相似文献   

8.
吸附蒸馏—复合新分离过程   总被引:11,自引:0,他引:11  
对连续吸附蒸馏过程进行了分析,该过程在恒沸或沸点相近物系的分离及需用吸附除去不纯物的精细化工产品提纯等方面显示了特别的优越性,并在所建立的吸附蒸馏实验装置中,对接近恒沸组成的乙醇-水物系和乙酸乙酯-水-正丁醇物系进行了分离实验,采用4A分子筛为吸附剂,分别得到了99.9%的乙醇和高纯度的乙度的乙酸乙酯及正丁醇。  相似文献   

9.
杨国军 《遵义科技》2010,38(4):7-10
文章通过对高纯钛中杂质的成分、分布及存在形式的分析,研究了低温下C、N、O等杂质对高纯钛冷加工及拉伸等性能的影响,并得出结论:严格控制原料海绵钛中杂质的含量,是保证高纯钛产品质量的关键。  相似文献   

10.
通过常压下简单蒸馏与分馏的实验研究,阐明双组分体系中温度平台与组分含量、沸点差值之间的关系,得出结论:分离和提纯有机物时,对于组分纯度不高或沸点较为接近的液体混合物,采用分馏方法可测出各组分的温度平台及沸点;若采用简单蒸馏方法,则不会出现明显的温度平台,只有高纯度液态化合物才能测出其沸点;蒸馏方法适用于沸点相差较大的液体混合物的分离。  相似文献   

11.
Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.  相似文献   

12.
何延凌 《科技信息》2008,(4):258-258
Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women's language from these perspectives: pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women's language, more attention should be paid to language use in social context. What's more, the linguistic phenomena in a speaking community can be understood more thoroughly.  相似文献   

13.
王慧 《科技信息》2008,(10):240-240
Wuthering Heights, Emily Bronte's only novel, was published in December of 1847 under the pseudonym Ellis Bell. The book did not gain immediate success, but it is now thought one of the finest novels in the English language. Catherine is the key character of this masterpiece, because everybody and everything center on her though she had a short life. We can understand this masterpiece better if we know Catherine well.  相似文献   

14.
The Williston Basin is a significant petroleum province, containing oil production zones that include the Middle Cambrian to Lower Ordovician, Upper Ordovician, Middle Devonian, Upper Devonian and Mississippian and within the Jurassic and Cretaceous. The oils of the Williston Basin exhibit a wide range of geochemical characteristics defined as "oil families", although the geochemical signature of the Cambrian Deadwood Formation and Lower Ordovician Winnipeg reservoired oils does not match any "oil family". Despite their close stratigraphic proximity, it is evident that the oils of the Lower Palaeozoic within the Williston Basin are distinct. This suggests the presence of a new "oil family" within the Williston Basin. Diagnostic geochemical signatures occur in the gasoline range chromatograms, within saturate fraction gas chromatograms and biomarker fingerprints. However, some of the established criteria and cross-plots that are currently used to segregate oils into distinct genetic families within the basin do not always meet with success, particularly when applied to the Lower Palaeozoic oils of the Deadwood and Winnipeg Formation.  相似文献   

15.
理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。  相似文献   

16.
As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.  相似文献   

17.
Location based services is promising due to its novel working style and contents.A software platform is proposed to provide application programs of typical location based services and support new applications developing efficiently. The analysis shows that this scheme is easy implemented, low cost and adapt to all kinds of mobile nework system.  相似文献   

18.
正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-  相似文献   

19.
We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-  相似文献   

20.
正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that  相似文献   

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