scholarly journals A Facile and Low-Cost Method to Produce Ultrapure 99.99999% Gallium

Materials ◽  
2018 ◽  
Vol 11 (11) ◽  
pp. 2308 ◽  
Author(s):  
Kefeng Pan ◽  
Ying Li ◽  
Jiawei Zhang ◽  
Qing Zhao

As one of the critical raw materials, very pure gallium is important for the semiconductor and photoelectric industry. Unfortunately, refining gallium to obtain a purity that exceeds 99.99999% is very difficult. In this paper, a new, facile and efficient continuous partial recrystallization method to prepare gallium of high purity is investigated. Impurity concentrations, segregation coefficients, and the purification effect were measured. The results indicated that the contaminating elements accumulated in the liquid phase along the crystal direction. The order of the removal ratio was Cu > Mg > Pb > Cr > Zn > Fe. This corresponded to the order of the experimentally obtained segregation coefficients for each impurity: Cu < Mg < Pb < Cr < Zn < Fe. The segregation coefficient of the impurities depended strongly on the crystallization rate. All observed impurity concentrations were substantially reduced, and the purity of the gallium obtained after our refinement exceeded 99.99999%.

2014 ◽  
Vol 852 ◽  
pp. 36-39
Author(s):  
Qun Shan Liu ◽  
Jun Xia Yan

By using scrap miscellaneouszinc materialas raw materials, a new technology with the help of two distillationsby fire method to produce zinc oxide was invented.The scrap miscellaneous zinc materialshave complex sources, containing dust, stone, iron and steel parts and other impurities, and zinc content is more than 15% over a wide range. The presence of zinc is in the form of pure metallic state, alloy state and oxidation state.Distillation process has two steps, the primary for removing the principal impurities and the second for zinc oxide purification. With less investment, low cost, simple equipment, easy operation, environmental protection and other advantages, this method is fit for production of high-purity zinc oxide and can also be used for the production of nanoscale high purity zinc oxide.


2012 ◽  
Vol 519 ◽  
pp. 92-95
Author(s):  
Feng Cao ◽  
Zhen Yu Fang ◽  
Fei Chen ◽  
Qiang Shen ◽  
Si Qing Wang ◽  
...  

Ammonia borane (AB) hydrides have been employed as disposable hydrogen (H2) sources for fuel cell applications, due to their high hydrogen capacity. In this paper, ammonia borane (AB) complex with high purity was synthesized by chemical method, using the low cost raw materials of NaBH4, CO2, and NH3. The thermal dynamic for the synthesis process is analyzed. The phase composition for the obtained ammonia borane (AB) complex powders was detected by X-ray diffraction (XRD) characterization. The results suggest that, very high purity ammonia borane (AB) complex powders were obtained, which was quite in agreement with the standard index of ammonia borane.


2020 ◽  
Vol 4 (1) ◽  
pp. 41-48
Author(s):  
Teodoro Astorga Amatosa ◽  
Michael E. Loretero

Bamboo is a lightweight and high-strength raw materials that encouraged researchers to investigate and explore, especially in the field of biocomposite and declared as one of the green-technology on the environment as fully accountable as eco-products. This research was to assess the technical feasibility of making single-layer experimental Medium-Density Particleboard panels from the bamboo waste of a three-year-old (Dendrocalamus asper). Waste materials were performed to produce composite materials using epoxy resin (C21H25C105) from a natural treatment by soaking with an average of pH 7.6 level of sea-water. Three different types of MDP produced, i.e., bamboo waste strip MDP (SMDP), bamboo waste chips MDP (CMDP) and bamboo waste mixed strip-chips MDP (MMDP) by following the same process. The experimental panels tested for their physical-mechanical properties according to the procedures defined by ASTM D1037-12. Conclusively, even the present study shows properties of MDP with higher and comparable to other composite materials; further research must be given better attention as potential substitute to be used as hardwood materials, especially in the production, design, and construction usage.


2019 ◽  
Author(s):  
Yu Wang ◽  
Nachuan Yang ◽  
Yi Shuai ◽  
Yunpeng Zhang ◽  
Kanghua Chen

1991 ◽  
Vol 24 (7) ◽  
pp. 277-284 ◽  
Author(s):  
E. Gomólka ◽  
B. Gomólka

Whenever possible, neutralization of alkaline wastewater should involve low-cost acid. It is conventional to make use of carbonic acid produced via the reaction of carbon dioxide (contained in flue gases) with water according to the following equation: Carbon dioxide content in the flue gas stream varies from 10% to 15%. The flue gas stream may either be passed to the wastewater contained in the recarbonizers, or. enter the scrubbers (which are continually sprayed with wastewater) from the bottom in oountercurrent. The reactors, in which recarbonation occurs, have the ability to expand the contact surface between gaseous and liquid phase. This can be achieved by gas phase dispersion in the liquid phase (bubbling), by liquid phase dispersion in the gas phase (spraying), or by bubbling and spraying, and mixing. These concurrent operations are carried out during motion of the disk aerator (which is a patent claim). The authors describe the functioning of the disk aerator, the composition of the wastewater produced during wet gasification of carbide, the chemistry of recarbonation and decarbonation, and the concept of applying the disk aerator so as to make the wastewater fit for reuse (after suitable neutralization) as feeding water in acetylene generators.


Metals ◽  
2018 ◽  
Vol 8 (9) ◽  
pp. 701 ◽  
Author(s):  
Lei Guo ◽  
Xiaochun Wen ◽  
Qipeng Bao ◽  
Zhancheng Guo

An investigation was made on the super-gravity aided rheorefining process of recycled 7075 aluminum alloy in order to remove tramp elements. The separation temperatures in this study were selected as 609 °C, 617 °C and 625 °C. And the gravity coefficients were set as 400 G, 700 G, 1000 G. The finely distributed impurity inclusions will aggregate to the grain boundaries of Al-enriched phase during heat treatment. In the field of super-gravity, the liquid phase composed of tramp elements Zn, Cu, Mg et al. will flow through the gaps between solid Al-enriched grains and form into filtrate. Both the weight of filtrate and removal ratio of tramp element improved with the increase of gravity coefficient. The total removal ratio of tramp element decreased with the fall of temperature due to the flowability deterioration of liquid phase. The time for effective separation of liquid/solid phases with super-gravity can be restricted within 1 min.


Resources ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 67
Author(s):  
Katarzyna Guzik ◽  
Krzysztof Galos ◽  
Alicja Kot-Niewiadomska ◽  
Toni Eerola ◽  
Pasi Eilu ◽  
...  

Major benefits and constraints related to mineral extraction within the EU have been identified on the examples of selected critical raw materials’ deposits. Analyzed case studies include the following ore deposits: Myszków Mo-W-Cu (Poland), Juomasuo Au-Co (Finland), S. Pedro das Águias W-Sn (Portugal), Penouta Nb-Ta-Sn (Spain), Norra Kärr REEs (Sweden) and Trælen graphite (Norway). They represent different stages of development, from the early/grassroot exploration stage, through advanced exploration and active mining, up to reopening of abandoned mines, and refer to different problems and constraints related to the possibility of exploitation commencement. The multi-criteria analysis of the cases has included geological and economic factors as well as environmental, land use, social acceptance and infrastructure factors. These factors, in terms of cost and benefit analysis, have been considered at three levels: local, country and EU levels. The analyzed cases indicated the major obstacles that occur in different stages of deposit development and need to be overcome in order to enable a new deposit exploitation commencement. These are environmental (Juomasuo and Myszków), spatial (Juomasuo) as well as social constraints (Norra Kärr, Juomasuo). In the analyzed cases, the most important constraints related to future deposit extraction occur primarily at a local level, while some important benefits are identified mainly at the country and the EU levels. These major benefits are related to securing long-term supplies for the national industries and strategically important EU industry sectors.


Materials ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 1826
Author(s):  
Mihaela Girtan ◽  
Antje Wittenberg ◽  
Maria Luisa Grilli ◽  
Daniel P. S. de Oliveira ◽  
Chiara Giosuè ◽  
...  

This editorial reports on a thorough analysis of the abundance and scarcity distribution of chemical elements and the minerals they form in the Earth, Sun, and Universe in connection with their number of neutrons and binding energy per nucleon. On one hand, understanding the elements’ formation and their specific properties related to their electronic and nucleonic structure may lead to understanding whether future solutions to replace certain elements or materials for specific technical applications are realistic. On the other hand, finding solutions to the critical availability of some of these elements is an urgent need. Even the analysis of the availability of scarce minerals from European Union sources leads to the suggestion that a wide-ranging approach is essential. These two fundamental assumptions represent also the logical approach that led the European Commission to ask for a multi-disciplinary effort from the scientific community to tackle the challenge of Critical Raw Materials. This editorial is also the story of one of the first fulcrum around which a wide network of material scientists gathered thanks to the support of the funding organization for research and innovation networks, COST (European Cooperation in Science and Technology).


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