摘要
铝酸钠溶液的碳酸化分解是烧结法氧化铝生产的关键工序,该工序产出的氢氧化铝经焙烧得到氧化铝,工业氧化铝的主要用途是作为电解铝的原料生产金属铝,市场需求十分巨大。较长时间以来由于受生产工艺条件和系统装置的制约,在碳酸化分解工序结晶析出的氢氧化铝45um以下颗粒含量高、二氧化硅析出量大,造成烧结法氧化铝产品粒度小、杂质含量高等缺陷,成为烧结法氧化铝产品质量提高的瓶颈限制。为提高氧化铝产品质量,从碳酸化分解工序入手,研究探讨优化生产工艺条件和装置的理论与工程应用方法,对于生产大颗粒、杂质含量少的氢氧化铝、提高产品质量和国内外市场竞争力具有重要的意义和工程应用价值。
本论文主要研究烧结法氧化铝生产过程中的碳酸化分解工序的工艺及装置。
1、以氢氧化铝砂状率为优化目标,分析碳酸化分解生产氢氧化铝工序的工艺流程、反应速度对碳酸化分解过程中二氧化碳吸收率、氢氧化铝结晶析出、砂状率的影响规律,通过增加结晶槽数量对连续碳酸化分解生产氢氧化铝的工艺流程进行优化,延长反应时间,改变各槽分解率匹配控制;并据实验数据分析验证了碳酸化连续分解工艺优化对提高结晶析出氢氧化铝粒度、降低杂质含量的效果和作用。
2、优化了碳酸化连续分解工业生产工艺条件的控制;分析了晶种颗粒、不同晶种添加量对氢氧化铝二氧化硅含量和粒度的影响,试验对比了晶种优化的效果;分析铝酸钠溶液纯度对氢氧化铝颗粒度和杂质含量的影响,优化连续碳酸化分解的最终分解率,控制二氧化硅的析出、提高产出氢氧化铝粒度。
3、研究铝酸钠溶液连续碳酸化分解的搅拌槽和提料装置,分别对搅拌形式、尺寸、槽底结构、挡板、转速等参数进行了优化,并分析研究了连续碳分条件下的过料方式,提高碳酸化分解生产氢氧化铝过程中二氧化碳气体吸收率,降低搅拌过程对氢氧化铝颗粒的破碎,提高氢氧化铝颗粒度;针对铝酸钠溶液碳酸化分解过程中管道及设备表面结晶这一不利现象,分析不同部位的不同诱因,从装置和工艺操作条件各方面进行了优化,消除由于结晶造成的操作准确性差及设备易损坏的影响。实现铝酸钠溶液连续碳酸化分解工业生产过程控制简便、工序运行平衡稳定。
将研究成果在国内烧结法氧化铝生产中推广,会有效地提高氢氧化铝质量,提高我国氧化铝的国际竞争力。
Al-sodium carbonate decomposition of alumina sintering is the key to the production process, the process of production of aluminum hydroxide has been a long time equipment and installation process conditions, with a small size, high levels of impurities shortcomings, Unable to meet market demand, the sintering of alumina powder products are facing a situation out, in order to improve the quality of alumina products, the production of large particles, impurities content of less aluminum hydroxide product, the process conditions of the carbonization must be optimizated.
The main thesis of this study sintering aluminum hydroxide production process of carbonization technology and equipment.
1. Sand-like aluminum hydroxide in order to optimize the target rate, the analysis of the decomposition of carbonate production process of aluminum hydroxide process, the speed of reaction of carbonation in the process of decomposition of carbon dioxide absorption rate, the crystallization of aluminum hydroxide precipitation, sand-like rate of the law, Crystallization increase the number of slots in a row on the decomposition of carbonate production of aluminum hydroxide to optimize the process, the extension of reaction time, the decomposition rate of change in the slot matching control; and, according to analysis of experimental data to verify the carbonate decomposition process of continuous optimization to improve the crystallization of the hydroxide precipitation Size aluminum, to reduce the effect of impurity content and function.
2. Optimizing the carbonation in a row break down industrial production process control; analysis of the seed particles of different seeds to add to the amount of aluminum hydroxide particle size and content of silicon dioxide, a comparison test to optimize the effectiveness of seed; analysis of the aluminum acid Sodium solution to the purity of aluminum hydroxide particle size and concentration of impurities, continuous optimization of the final decomposition of carbonate decomposition rate, control of the silica precipitation to increase grain output of aluminum hydroxide.
3. Research sodium aluminate solution for the decomposition of carbonate and stirred tank to feed device, respectively, in the form of mixing, size, structure from the bottom, tailgate, speed, and other parameters are optimized, and analysis of the carbon in a row at the conditions have been expected Ways to enhance decomposition of carbonate production of aluminum hydroxide in the process of carbon dioxide absorption rate and reduce the process of mixing aluminum hydroxide particles broken, aluminum hydroxide to increase particle size;Aluminum for sodium carbonate in the process of decomposition of pipelines and equipment on the surface crystallization of this adverse phenomenon, the analysis of the different parts of different incentives, technology and devices from various operating conditions are optimized, due to the elimination of crystal caused by the poor accuracy of the operations and equipment Easily damaged. Sodium aluminate solution to achieve continuous carbonization of industrial production process control simple processes running balance and stability.
Research results in the domestic production of alumina sintering promotion, will effectively enhance the quality of aluminum hydroxide, aluminum oxide to improve our international competitiveness.
引文
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