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The dissolution mechanism of hemimorphite in NH3-(NH4)2SO4-H2O system at 298.15 K was investigated by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) analysis. The results show that hemimorphite is soluble in NH3-(NH4)2SO4-H2O system and its residue exists in the form of an amorphous SiO2 layer on the hemimorphite surface. The XPS data also indicate that the Si 2p3/2 and O ls spectra of the hemimorphite are broadened and shift to higher binding energies and their binding energies are closer to silica with an increase of total ammonia and time. Solubility of hemimorphite in NH3-(NH4)2SO4-H2O system was measured by means of isothermal solution method at 298.15 K based on the study of the dissolution mechanism of hemimorphite. The results show that the solubility of zinc in solution increases firstly and then decreases with the increase of cr(NH3) (total ammonia concentration) at different NH3/NH4^+ ratios. The solubility of silicon in solution decreases from 0.0334 mol/kg in ct(NH3)-4.1245 mol/kg NH3-(NH4)2SO4-H2O solution to 0.0046 mol/kg in cT(NH3)=7.6035 mol/kg NH3-(NH4)2SO4-H2O solution. 相似文献
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磺化酚酞型聚醚砜/改性蒙脱土纳米复合膜的研究 总被引:1,自引:0,他引:1
用季胺盐改性蒙脱土和磺化酚酞型聚醚砜首次制得了磺化酚酞型聚醚砜/改性蒙脱土纳米复合质子交换膜,并用1H NMR、SEM、FT-IR等分析手段对其进行了表征,测定了复合膜的质子导电率.研究结果表明:改性蒙脱土以纳米颗粒形式分散于磺化酚酞型聚醚砜聚合物基体中;在相同测试温度下,磺化酚酞型聚醚砜/改性蒙脱土纳米复合质子交换膜的质子电导率随着改性蒙脱土含量增加而增加,添加10%(wt)改性蒙脱土的复合质子交换膜,在80℃下的质子电导率为8.53×10-4S/cm. 相似文献
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The zinc-containing dust was oxidatively pretreated with calcium hypochlorite,subsequently leached with ammonia/ammonium bicarbonate solution to obtain the ammoniacal leaching solution,and zinc oxide was produced by ammonia distillation of the ammoniacal leaching solution and subsequent calcination. The elements of iron and manganese could not be detected in ammoniacal leaching solution,and the extraction rate of zinc was 98.2% in ammoniacal leaching process. The zinc oxide content in the product is 99.5%(ω),and the contents of iron and manganese in the product were 0.002 8‰ and 0.000 84‰(ω), respectively. The analyses of the valence states of iron and manganese in the zinc-containing dust with and without pretreatment were performed by chemical analysis and XPS,and the possible oxidation mechanism of the oxidative pretreatment of the dust was discussed. It is concluded that Fe 2+-oxide and Mn 2+-oxide in the dust were oxidized to Fe 3+-oxide and/or its hydrate and Mn 4+-oxide and/or its hydrate by calcium hypochlorite during the oxidative pretreatment process,respectively. 相似文献
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介绍了新型聚乙烯(PE)烧结膜微滤设备的结构和性能特点及其工作原理和技术参数.在工业生产过程中分别采用PE烧结膜微滤设备和无机陶瓷膜微滤设备集中净化处理硬质合金水基磨削液.结果表明,在40 m3/h过滤流量和1 μm过滤精度下,PE烧结膜微滤设备只须采用简单的"终端过滤+反吹/反洗"防污堵措施,就能保证连续运行3个月而不出现流量衰减迹象.与无机陶瓷膜微滤设备相比,PE烧结膜微滤设备更具经济性和环保性,完全能满足硬质合金磨削液集中净化处理的要求. 相似文献
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In order to provide references for selecting highly efficient red mud flocculants, the behaviour of polyacrylamidomethyltrimethyl ammonium chloride (PATAC) in red mud separation process was investigated. PATAC was employed as a flocculant for red mud separation from the caustic aluminate liquor at 95 ℃. The used red mud was generated from Chinese diaspore bauxite in Bayer process of alumina production. And the changes of PATAC before or after being treated in caustic solution at 95 ℃ were studied by thermogravimetry (TG) and Fourier transform infrared (FTIR) spectral analysis. The results show that PATAC fails in effectively focculating red mud and PATAC is readily converted to a quaternary ammonium hydroxide (PATAH) in caustic solution. PATAH can be decomposed to a new polymer (HPATAH) even at 95 ℃. Furthermore, there is an intramolecular hydrogen bond formed in the HPATAH polymer chain with two functional groups of--CH2--OH and --CONH2. Therefore, the poor flocculation property of PATAC for red mud separation can be attributed to the thermal decomposition of PATAC in the caustic red mud slurry at 95 ℃ and the formation of intramolecular hydrogen bond in the polymer chain of HPATAH during the thermal decomposition, which causes the absorbable functional groups of PATAC to decrease greatly. 相似文献
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