摘要
高品质铝土矿在我国属于紧缺性矿产资源,我国有大量高硫铝土矿资源,但高硫铝土矿冶炼会降低Al2O3溶出率、降低赤泥沉降性能、污染氢氧化铝产品、腐蚀生产设备等,因此高硫铝土矿脱硫技术成为实现其高效综合利用、缓解铝土矿资源短缺的关键.目前高硫铝土矿脱硫技术主要分为预处理脱硫和溶出过程脱硫.预处理脱硫包括浮选法、焙烧法、电化学脱硫、微生物脱硫等.浮选法适合于含硫较低的铝矿石资源,对于低品位、高硫含量的铝矿石则存在浮选药剂用量大、废水排放量大等问题;焙烧法脱硫效率高,但传统堆积焙烧存在焙烧时间长、能耗高等问题;电化学脱硫具有低温、常压、高脱硫率、无二次污染等优点,但存在能耗高、生产规模受限制等问题;微生物脱硫生产成本和能耗较低、环保性较高,但特定菌种对生长环境要求苛刻,培育菌种周期长.溶出过程脱硫包括氧化蒸发法脱硫、沉淀法脱硫和石灰法脱硫等.氧化蒸发法能够清除铝酸钠溶液中大部分S2-,但对其他形态硫氧化效果不明显;沉淀法脱硫操作较为简单,但存在脱硫剂成本高,难以应用于实际生产的问题;石灰法只能脱除溶液中SO42-,对其他类型硫离子并未产生显著去除作用.未来,建议从以下几个方向着手解决高硫铝土矿脱硫问题:开发低温高效、低能耗焙烧工艺;改善或者研发新型脱硫捕收剂;筛选高效、易培育菌种,研究混合菌脱硫效果.
Abstract
Bauxite resources are a scarce mineral resource in China,with a large amount of high sulfur bauxite resources.However,the smelting of high sulfur bauxite will reduce the Al2O3 leaching rate,decrease the settling performance of red mud,pollute aluminum hydroxide products,and corrode production equipment.Therefore,desulfurization technology of high sulfur bauxite has become the key to achieving efficient and comprehensive utilization and alleviating the shortage of bauxite resources.At present,the desulfurization technology of high sulfur bauxite mainly includes pre-treatment desulfurization and leaching process desulfurization.Pre-treatment desulfurization includes flotation,calcination,electrochemical desulfurization,microbial desulfurization,etc.The flotation method is suitable for aluminum ore resources with low sulfur content.However,for low-grade and high sulfur aluminum ore,there are problems such as high dosage of flotation reagents and large discharge of wastewater;The desulfurization efficiency of the roasting method is high,but traditional stacking roasting has problems such as long roasting time and high energy consumption;Electrochemical desulfurization has advantages such as low temperature,atmospheric pressure,high desulfurization rate,and no secondary pollution,but there are problems such as high energy consumption and limited production scale;Microbial desulfurization has lower production costs and energy consumption,and higher environmental friendliness,but specific bacterial strains have strict requirements for growth environment and long cultivation cycle.The desulfurization process of dissolution includes oxidation evaporation desulfurization,precipitation desulfurization,and lime desulfurization.The oxidation evaporation method can remove most of S2-from sodium aluminate solution,but its effect on the oxidation of other forms of sulfur is not significant;The precipitation method for desulfurization is relatively simple,but it has the problem of high cost of desulfurizers and difficulty in practical production;The lime method can only remove SO42-from the solution and does not have a significant removal effect on other types of sulfur ions.In the future,it is recommended to address the desulfurization problem of high sulfur bauxite in the following directions:developing low-temperature,high-efficiency,and low-energy consumption roasting processes;Improve or develop new desulfurization and capture agents;Screening efficient and easy to cultivate bacterial strains,and studying the desulfurization effect of mixed bacteria.
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