Determination of dissolution rate of alumina is one of the classical problems in aluminum electrolysis. A novel method which can measure the dissolution rate of alumina was presented. Effect of factors on dissolution ...Determination of dissolution rate of alumina is one of the classical problems in aluminum electrolysis. A novel method which can measure the dissolution rate of alumina was presented. Effect of factors on dissolution rate of alumina was studied intuitively and roundly using transparent quartz electrobath and image analysis techniques. Images about dissolution process of alumina were taken at an interval of fixed time from transparent quartz electrobath of double rooms. Gabor wavelet transforms were used for extracting and describing the texture features of each image. After subsampling several times, the dissolution rate of alumina was computed using these texture features in local neighborhood of samples. Regression equation of the dissolution rate of alumina was obtained using these dissolution rates. Experiments show that the regression equation of the dissolution rate of alumina is y=-0.000 5x^3＋0.024 0x^2-0.287 3x＋ 1.276 7 for Na3AIF6-AIF3-Al2O3-CaF2-LiF- MgF2 system at 920 ℃.展开更多
A series of glass are synthesized via a melt quenching technique based on the Li_(2)O-Ni O-P_(2)O_(5) system.The concentration of nickel oxide varies from 5%to 15%in molar fraction.XRD pattern verifies the amorphous n...A series of glass are synthesized via a melt quenching technique based on the Li_(2)O-Ni O-P_(2)O_(5) system.The concentration of nickel oxide varies from 5%to 15%in molar fraction.XRD pattern verifies the amorphous nature of prepared glass samples with 5%,and 10%nickel oxide in molar fraction.While Li_(3)P and Ni_(2)P_(4)O_(12)phases are precipitated with a high nickel content up to 15%in molar fraction.As nickel is substituted for lithium,a systematic increase in glass transition temperature(T_(g))and glass softening temperatures(T_(s))is observed.This is greatly related to the increased structure,coherence in the glass network.Structural investigation showed that Ni_(2+) spectra are present in both octahedral and tetrahedral sites.Physical properties such as glass density((2.38±0.1)-(2.46±0.1)g/cm^(3)),and molar volume((42.28±0.1)-(39.15±0.1)cm^(3)/mol)are examined.The NiO/Li_(2)O replacements led to a decrease in the dissolution rate of the resultant amorphous materials from 1.53×10^(-5)to 3.20×10^(-6)g/(cm^(2)·min).Thermal expansion coefficients CTE of the glasses are diverse from 157×10^(-7) to 96×10^(-7)℃^(-1) over the temperature range of 25-250℃.The prepared glasses are expected to be useful as a low-temperature sealing material.展开更多
基金Projects(51101104,51072121) supported by the National Natural Science Foundation of ChinaProject(LS2010109) supported by the Key Laboratory Foundation of Liaoning Province,China
文摘Determination of dissolution rate of alumina is one of the classical problems in aluminum electrolysis. A novel method which can measure the dissolution rate of alumina was presented. Effect of factors on dissolution rate of alumina was studied intuitively and roundly using transparent quartz electrobath and image analysis techniques. Images about dissolution process of alumina were taken at an interval of fixed time from transparent quartz electrobath of double rooms. Gabor wavelet transforms were used for extracting and describing the texture features of each image. After subsampling several times, the dissolution rate of alumina was computed using these texture features in local neighborhood of samples. Regression equation of the dissolution rate of alumina was obtained using these dissolution rates. Experiments show that the regression equation of the dissolution rate of alumina is y=-0.000 5x^3＋0.024 0x^2-0.287 3x＋ 1.276 7 for Na3AIF6-AIF3-Al2O3-CaF2-LiF- MgF2 system at 920 ℃.
文摘A series of glass are synthesized via a melt quenching technique based on the Li_(2)O-Ni O-P_(2)O_(5) system.The concentration of nickel oxide varies from 5%to 15%in molar fraction.XRD pattern verifies the amorphous nature of prepared glass samples with 5%,and 10%nickel oxide in molar fraction.While Li_(3)P and Ni_(2)P_(4)O_(12)phases are precipitated with a high nickel content up to 15%in molar fraction.As nickel is substituted for lithium,a systematic increase in glass transition temperature(T_(g))and glass softening temperatures(T_(s))is observed.This is greatly related to the increased structure,coherence in the glass network.Structural investigation showed that Ni_(2+) spectra are present in both octahedral and tetrahedral sites.Physical properties such as glass density((2.38±0.1)-(2.46±0.1)g/cm^(3)),and molar volume((42.28±0.1)-(39.15±0.1)cm^(3)/mol)are examined.The NiO/Li_(2)O replacements led to a decrease in the dissolution rate of the resultant amorphous materials from 1.53×10^(-5)to 3.20×10^(-6)g/(cm^(2)·min).Thermal expansion coefficients CTE of the glasses are diverse from 157×10^(-7) to 96×10^(-7)℃^(-1) over the temperature range of 25-250℃.The prepared glasses are expected to be useful as a low-temperature sealing material.
