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241.
On the basis of the practical production of non-oriented silicon steel, the formation of Mg O·Al2O3 inclusions was analyzed in the process of "basic oxygen furnace(BOF) → RH → compact strip production(CSP)". The thermodynamic and kinetic conditions of the formation of Mg O·Al2O3 inclusions were discussed, and the behavior of slag entrapment in molten steel during RH refining was simulated by computational fluid dynamics(CFD) software. The results showed that the Mg O/Al2O3 mass ratio was in the range from 0.005 to 0.017 and that Mg O·Al2O3 inclusions were not observed before the RH refining process. In contrast, the Mg O/Al2O3 mass ratio was in the range from 0.30 to 0.50, and the percentage of Mg O·Al2O3 spinel inclusions reached 58.4% of the total inclusions after the RH refining process. The compositions of the slag were similar to those of the inclusions; furthermore, the critical velocity of slag entrapment was calculated to be 0.45 m·s^-1 at an argon flow rate of 698 L·min^-1, as simulated using CFD software. When the test steel was in equilibrium with the slag, [Mg] was 0.00024wt%–0.00028wt% and [Al]s was 0.31wt%–0.37wt%; these concentrations were theoretically calculated to fall within the Mg O·Al2O3formation zone, thereby leading to the formation of Mg O·Al2O3 inclusions in the steel. Thus, the formation of Mg O·Al2O3 inclusions would be inhibited by reducing the quantity of slag entrapment, controlling the roughing slag during casting, and controlling the composition of the slag and the Mg O content in the ladle refractory. 相似文献
242.
In this study, the removal of phenol using immobilized soybean seed hull peroxidase was investigated. The soybean peroxidase (SBP) enzymes were extracted from the raw soybean seed hulls and entrapped within hybrid (silica sol‐gel/alginate) particles. An aqueous sol‐gel route was preferred over an alkoxide route to prepare the silica sol‐gel suspension. A cluster of nozzles was designed for the bulk production of the biocatalysts. Upto 85% phenol was polymerized using the fabricated biocatalysts under the optimized conditions. Viability studies and repeated application/regeneration of entrapped enzymes were carried out. Surface conditions and the pore structure of the particles were studied using SEM before the reaction and after the reaction. The study indicates that these particles are promising biocatalysts for fluidized bed or packed bed reactors. This study represents the first investigation of enzymatic reactions that form a coating on the immobilized biocatalyst. 相似文献
243.
《分离科学与技术》2012,47(6):1017-1022
Arsenic toxicity has become a major concern worldwide. Remediation of this problem needs the development of technology with improved materials and systems with high efficiency. We have demonstrated a simple and efficient method for the absolute removal of As(III) from high concentration As(III) treated water with a low contact time period. The process of As(III) adsorption follows pseudo-second-order kinetic model. The mechanism for high-adsorption efficiency is attributed to fatty acid binding domain-mediated surface conjugation of ultrafine Fe2O3 nanoparticles with As(III). We have also ensured the simultaneous separation of arsenic sorbed nanoparticles by entrapping them in hydrophilic calcium alginate beads and thereby a pure arsenic free solution has been obtained. 相似文献
244.
针对某钢厂250 t钢包底吹氩气过程进行水模型实验和数值模拟,考察了吹气量和渣层厚度对卷渣行为和吹气量、渣层厚度及透气砖透气性能对钢液裸露面的影响,分析了卷渣形成机理. 结果表明,吹气量对卷渣形成具有决定性作用,吹气量控制在0.96 m3/h(对应实际流量69 m3/h)以下可避免卷渣;随着吹气量的增加,钢液裸露面积逐渐增大,当吹气量达到0.70 m3/h时,钢液裸露面积百分比约达14%,继续增大吹气量,其增加幅度变缓;随着渣层厚度的增加,临界卷渣吹气量和钢液裸露面积逐渐减小,以37 mm(对应实际渣厚150 mm)厚渣层覆盖,可有效防止钢液二次氧化;透气砖堵塞对钢液裸露面积影响较大,顶部钢液形成两不同大小的裸露亮圈,并加重对包壁耐材的冲刷与侵蚀,降低钢的洁净度. 工艺优化后,钢包水口结瘤率降低至0.1%以下,且可降低生产成本. 相似文献
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用壳聚糖- 海藻酸钠微囊技术制备一系列叶绿素亚铁微胶囊,以包封率和载药量作为制备工艺优化指标,通过正交试验得出最优方案。考察微胶囊在模拟胃液和模拟肠液中的控制释放效果。结果显示,制备该微胶囊的最优方案为海藻酸钠15mg/mL、壳聚糖4mg/mL、氯化钙20mg/mL、芯材与海藻酸钠的质量比1:4。所得胶囊在模拟胃液和模拟肠液中缓释性能良好。 相似文献
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