Papers by Keyword: Na2CO3

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Authors: Zhi Yong Jia
Abstract: A general sonochemical approach that allows for the facile, rapid synthesis of MSn(OH)6 (M=Ba, Ca, Sr) one-dimension (1D) nanostructures has been developed. The resulting CaSn(OH)6 products possessed a nanotubular structure, while SrSn(OH)6 and BaSn(OH)6 showed nanowire-like structures. The as-synthesized MSn(OH)6 products were characterized by XRD, SEM and TEM techniques. The BaSn(OH)6 nanowires, CaSn(OH)6 nanotubes, and SrSn(OH)6 nanowires share different growth mechanisms because they take different crystal structures. However, we found that for all the three materials, both the ultrasound irradiation and the presence of Na2CO3 in the synthetic procedure had an impact on the homogeneous nucleation and fast growth of 1D MSn(OH)6 nanostructures. This approach represents a successful example for the fast construction of inorganic innovative nanostructures in the absence of any surfactants.
Authors: Jun Cong Wei, Xiu Mei Ji, Jian Kun Huang, Chun Hui Gao, Jun Bo Tu
Abstract: The effects of addition of silicon powder (1 wt. %) and Na2CO3 (converting to additional 0.5%, 1% Na2O) on the hot modulus of rupture (HMOR) of MgO-Al-C bricks were investigated. MgO-Al-C refractories were prepared by using fused magnesia and graphite flake as main starting materials, and Si, Na2CO3 or both as additives. Its phase composition and microstructure were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), and EDS. The results showed that the HMOR of MgO-Al-C bricks increased slightly with addition of Si powder. However, the HMOR decreased when adding Na2CO3 and Si powder together. Moreover, the HMOR deduced with the increase of Na2CO3 content. The mechanism is that Al powder reacted to form fibrous Al4C3 and AlN, which could improve the HMOR. When silicon was added, β-SiC and M2S were formed, which could fill the passages and pores. So the densification and strength were improved. The addition of Na2CO3 could promote the oxidation of Al powder to form Al2O3, and inhibit the formation of Al4C3 and AlN. Hence the strength of MgO-Al-C deduced.
Authors: Xiu Mei Ji, Jun Cong Wei, Jian Kun Huang, Chun Hui Gao, Jun Bo Tu
Abstract: To improve the hydration resistance of MgO-Al-C bricks, Na2CO3 was chosen as an additive through thermodynamic calculation. MgO-Al-C refractories were prepared by using Si, Na2CO3 or both as additives. The effects of additives on the hydration resistance of specimens were investigated. XRD was conducted to determine the phase composition. The results showed that the hydration resistance of MgO-Al-C bricks would be improved slightly with addition of only Si due to the densification of the structure. When Na2CO3 and Si were added together, the hydration resistance would be improved remarkably. The mechanism is that Na2CO3 could decompose to give off O2 during heating, which could promote the oxidation of Al metal and inhibit the formation of Al4C3 and AlN.
Authors: Ji Sun Im, Soo Jin Park, Young Seak Lee
Abstract: In this work, carbon nanofibers(CNFs) were prepared by using electrospinning method. Phosphoric acid and sodium carbonate activation of CNFs were conducted to increase surface area and pore volume. Pore structures of activated CNFs were developed with increasing surface area and pore volume through activation. Specific surface area increased about 60 times and total pore volume developed around 120 times. Activated CNFs have different pore distribution with different chemical agent.
Authors: Ding Guo, Jun Ding, Cheng Ji Deng, Hong Xi Zhu, Xiao Jun Zhang, Wen Jie Yuan
Abstract: Using the natural forsterite and Na2CO3 as a raw material, the forsterite lightweight material was prepared in Na2CO3 molten salt. The reaction between forsterite and Na2CO3 and sintering mechanism of forsterite were studied in the paper. The sintering temperature was 1000 °C, 1100 °C, and the holding time was 1 h, 3 h, 5 h, 7 h, 10 h, respectively. The sintered samples were characterized by XRD and SEM for their microstructure and phase composition analysis which determined the mechanism of the chemical reaction and sintering in the sintering process. The product of Na2MgSiO4 phase in In earlier period of the reactions promoted the rearrangement of particles of forsterite in the initial stage of sintering process. The sintering mechanism was mainly controlled by the diffusion mechanism.
Authors: Lan Hua Zhou, Fu Hong Zeng
Abstract: Vanadic-titanomagnetite-coal mixed pellets with minor addition of Na2CO3 were reduced isothermally at 900°C, 945°C, 1100°C, 1255.4°C and 1300°C. The variables parameters studied are temperature, the amount of carbon and the amount of Na2CO3 as additive. The experiment was designed with the technique of orthogonal regression in order to quantitatively assess the effect of each variable and the interactional effect of different variables. It is found that temperature, the amount of carbon and the amount of Na2CO3 as additive substantially influence the degree of reduction and metallization, and the presence of Na2CO3 can increase the reducibility of the pellets. The interaction of temperature and the amount of Na2CO3 have negative influences on the degree of reduction and metallization.
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