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碱石灰烧结法从粉煤灰中提取氧化铝的最佳工艺条件是:生料配比[N/R]为0.95,[C/S]为2.0,烧结温度1250℃,烧结时间30min;熟料溶出温度80℃,时间30min,调整液αK为1.60±0.05,氧化铝浓度10g/L,碳酸钠浓度12g/L;采用三段脱硅,精液硅量指数>600,精液分解温度90℃,种子加量20g/L。证明用粉煤灰碱-石灰烧结法生产氧化铝技术上可行,同时,提出了碱石灰烧结法生产粗氢铝后再重溶及低浓度处理粉煤灰联合生产水玻璃的工业应用改进途径。 相似文献
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梁春来 《稀有金属与硬质合金》1993,(Z1)
本文归纳分析了高铝低铁熟料烧成的烧结特性、窑皮挂结和维护要点。指出高铝低铁熟料烧成烧结温度高,烧成温度范围宽,溶出率高,但表层窑皮致密性较差,维护不好容易跨落。 相似文献
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霞石烧成过程及放射性核素研究 总被引:1,自引:0,他引:1
考察了实验室条件下霞石石灰石的烧成温度,分析了烧成机理,同时研究核素在烧成过程中的损失。做出温度—熟料Al2O3溶出率曲线和温度—体积收缩率曲线。结果表明,该配料的烧成温度区间为1267~1350℃。烧成过程中,会伴随有少量Na2O、K2O的挥发。由于挥发产物返回备料,并最终进入熟料,因此,核素的此种少量挥发行为对核素平衡不产生影响。 相似文献
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通过对高A/s熟料烧结温度范围的确定,分别在欠烧温度、近烧温度和正烧温度下制备熟料。对不同温度下烧制的熟料进行了物相分析、溶出及赤泥沉降性能试验研究。结果表明,高铝硅比熟料正烧结测试高,烧结测试范围宽,根据高A/S熟料的烧结特性,在低于正烧结测试高于近烧温度的条件下制备的熟料,能够满足工业生产对熟料质量的要求。 相似文献
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通过X射线衍射分析了粉煤灰的物相结构,采用焙烧单因素试验和正交试验探索硫酸氢铵焙烧法提取粉煤灰中氧化铝的工艺条件。结果表明,在硫酸氢铵与粉煤灰质量比为8.5∶1、焙烧温度420℃、焙烧时间60min的条件下,氧化铝的提取率可达84.5%。焙烧后熟料在下述最佳条件下氧化铝的溶出率可达到95.9%:溶出温度90℃,液固比8∶1,搅拌速率400r/min,溶出时间70min。 相似文献
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Alumina Solubility and Diffusion Coefficient of the Dissolved Alumina Species in Low-Temperature Fluoride Electrolytes 总被引:1,自引:0,他引:1
The solubility of alumina was measured by rotating an alumina cylinder (~500 rpm) in a high-purity melt for ~3 to 6 hours,
crushing and sampling the frozen melt, and determining the oxygen content in a Leco analyzer. The alumina solubilities determined
were as follows: (1) 3.2 ± 0.3 wt pct in NaF-AlF3 eutectic at 1023 K (750 °C); (2) 3.0 ± 0.3 wt pct in NaF-AlF3-CaF2 (5 wt pct) at 1023 K (750 °C); and (3) 5.2 ± 0.5 wt pct in a KF-AlF3 eutectic at 1003 K (730 °C). The alumina solubility in the KF-AlF3 eutectic was 2 wt pct more than in the sodium analogue, offering the possibility of operating a low-temperature aluminum
smelting cell without the need for an alumina slurry. The diffusion coefficient of the dissolved alumina species was determined
in the NaF-AlF3 eutectic at 1023 K (750 °C) using the rotating disc method and applying the Levich equation. Through a limited range of rotation
rates, the system seemed to be mass-transfer controlled, and the diffusion coefficient was estimated to be in the range 1.8
to 2.2 × 10−6 cm2 s−1. This value is about five times lower than the values encountered at traditional aluminum smelting temperatures (~1233 K
(960 °C)) and would result in relatively low mass transfer coefficients. 相似文献
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Fluoride is a potentially toxic ion that occurs in aquifers both naturally and as a result of anthropogenic activity. Sometimes remediation of the aquifer is required. One potential aquifer decontamination strategy is an “interception-sorption trench”—one of a number of “reactive wall” technologies. This remediation strategy relies upon natural hydraulic gradients to transport the fluoride through the aquifer to the interception-sorption trench where it partitions onto a strong sorbent—alumina. In this paper, the focus is on the development and calibration of an equilibrium-based geochemical model that will be employed in the development of a quantitative reactive transport model, which in turn will be used for the design of an interception-sorption trench. The geochemical model described here takes into account a variety of ions likely to be present in a sandy aquifer, chemical activities, and the surface charge on the alumina. The model is calibrated over a wide pH range and for high initial fluoride concentrations using experimental results obtained from batch tests. It is found that pH dependent equilibrium constants are needed to capture the behavior of the experimentally observed fluoride sorption. The presence of sodium sulfate in solution is investigated, and it is found that sodium significantly interferes with the sorption of fluoride onto alumina under alkaline conditions. The geochemical model indicates that under acidic conditions, the alumina may release potentially large and unacceptable concentrations of aluminum into the aquifer. As a way of managing this potential problem, it is proposed that aluminum concentrations in the pore fluid may be mitigated by the inclusion of tree bark within the interception-sorption trench. 相似文献
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详细分析了电解槽本体氧化铝漏料的5种原因和外围设备漏料的3种情况;介绍了成功的改进经验和解决问题的建议,对电解铝生产有重要的指导意义。 相似文献
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烧结法氧化铝硅渣中回收氧化铝的研究与应用 总被引:1,自引:0,他引:1
硅渣及其附液中舍氧化铝,返回配料造成无效循环,使工序产能降低。试验发现固相钙硅渣在碳酸钠溶液中能分解溶出氧化铝。在工业实践中,用碳分母液溶出混合硅渣,控制适当条件可使固相中氧化铝的回收率达到29.16%,附液中氧化铝的回收率达到57.4%。在烧结法氧化铝工厂熟料量不变的条件下,可增加氧化铝产量,降低生产成本,还可获得增产所带来的销售利润。 相似文献
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中铝山西分公司独家采用的拜耳法赤泥旋流器一螺旋分级机除砂工艺,工艺简单,除去了赤泥中的大颗粒粗砂,对沉降槽、赤泥过滤机的稳定运行起到了重要作用。 相似文献
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通过改变絮凝剂的添加量和添加方式,对拜耳法赤泥沉降分离的效果进行研究。结果表明,絮凝剂的添加量对赤泥沉降分离效果有重要影响,合适的添加量为0.02%~0.04%,二次添加比一次添加的效果要好,添加絮凝剂还能有效降低赤泥的压缩液固比。 相似文献
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介绍电除尘器在氧化铝焙烧过程中的应用,重点介绍了德国鲁奇公司电除尘器的气流均布板、极板、极线及振打装置等内部结构和高压电气、自控系统的特点以及成功应用。 相似文献