中低品位氧化锌矿清洁高效利用的机理研究

Low grade zinc oxide ore is important zinc resource, and so far, has not been reasonable utilized. The exhausting of the high grade zinc oxide ore resources makes the exploitation and utilization of the low grade zinc oxide ore urgently. In this study, the (NH4)2SO4 is employed to treat zinc oxide ore to realize the separation of Zn and SiO2, PbO. The reaction process and transformation mechanism of the components containing zinc in zinc oxide ore with (NH4)2SO4 are studied, and the transformation behavior of those components with zinc are confirmed. The H2SO4 is used to absorb the calcinating offgas to prepare (NH4)2SO4, which is reversed to treat zinc oxide ore. The ZnSO4 solution purified is used to prepare Zn products. NaOH is used to calcine the residue of zinc extraction from the zinc oxide ore, and the Pb and Si are transformed into soluble Na2PbO2 and Na2SiO3 then dissolved in solution to separate from Fe, through which the transformation process and mechanism of the reaction components in the slag in molten NaOH are obained, and the transformation behavior of the reaction components and the reaction dynamics are investigated. The solution is split-step carbonated by CO2 to yield SiO2, PbO precipitates and Na2CO3 solution, and the transformation process and behavior of the phases in carbonation process are studied. The solution is causticized by CaO, then the CaCO3 precipitate and NaOH solution are obtained, and NaOH solution is evaporation crystallization to return to calcine the residue after zinc extraction. CaCO3 is calcined to decompose to CaO and CO2, whih are cyclic used. The whole process achieves the comprehensive extraction of the value components in zinc oxide ore and realizes the cyclic utilization of (NH4)2SO4, NaOH, CaO and CO2. Finally, the clean and effictive comprehensive utilization of the low grade zinc oxide ore is achieved.

中低品位氧化锌矿是重要的锌资源，迄今尚未得到合理利用。高品位锌矿资源的日益枯竭，使得中低品位氧化锌矿的开发利用显得尤为迫切。本研究采用硫酸铵处理氧化锌矿分离锌和硅铅，研究氧化锌矿中含锌组元与硫酸铵反应的反应过程和转化机制，确定含锌组元的转化行为；硫酸吸收尾气得硫酸铵返回，硫酸锌溶液净化制备锌产品；采用NaOH焙烧提锌渣，硅和铅转变为可溶的Na2SiO3和Na2PbO2进入溶液与铁分离，确定提锌渣中反应组元在熔融碱中的转化过程和转化机制，确定反应组元的转化行为及反应动力学；将溶液分步碳分得到SiO2、PbO沉淀和碳酸钠溶液，明确碳分过程的物相转化过程和行为，CaO苛化溶液得到NaOH溶液和CaCO3沉淀，NaOH蒸浓结晶返回焙烧提锌渣，煅烧CaCO3得CO2和CaO再循环。整个路线综合提取氧化锌矿中的有价组分，硫酸铵、NaOH、CO2、CaO循环利用，最终实现中低品位氧化锌矿的清洁高效利用。

高品位锌矿资源的日益枯竭，使得中低品位氧化锌矿的开发利用显得尤为重要。如何有效利用中低品位氧化锌矿是世界性的问题。课题以中低品位氧化锌矿为研究对象，旨在开发一条绿色化、高附加值综合利用氧化锌矿的工艺路线。课题研究了：(1). 氧化锌矿中含锌组元与硫酸铵反应的反应过程和转化规律及含锌组元在复杂体系下的转化行为，研究了溶出液的净化。(2). 研究了提锌渣中反应组元在熔融碱中的转化过程和转化行为。(3). 研究了Na2SiO3溶液的碳分过程和物相的转化过程及Na2PbO2对Na2SiO3碳分过程的影响和作用。(4). 研究了碳酸氢铵焙烧氧化锌矿及转化法提取铅锶。(5). 研究了氢氧化钠熔融焙烧硅酸锌和氧化锌矿的反应过程。(6). 研究了上述反应过程的动力学。(7). 研究了反应介质硫酸铵、氢氧化钠的循环，并制备了多形貌氧化锌、二氧化硅、氧化铅及碳酸钙产品。研究表明：(1). 碳酸锌及氧化锌、硅酸锌与硫酸铵反应生成硫酸锌铵，硫酸锌铵分解得到氧化锌。400℃以上得到硫酸铅和硫酸钙。铁氧化物与硫酸铵反应得到硫酸铁铵，并逐步分解得到硫酸铁。(2). 硅化合物与氢氧化钠反应得到Na2SiO3，升温转化为Na4SiO4。铅化合物与氢氧化钠反应生成Na4PbO4升温得到Na6PbO5。(3). 得到了Na2SiO3溶液碳分的动力学曲线，得到了三种碱性溶液碳分的pH值范围。(4). 硫酸铵焙烧氧化锌矿符合界面化学反应控制；溶出过程符合无固体产物层生成的外扩散控制；得到了Na2SiO3溶液碳分的动力学曲线；提取铅锶受有固体产物层生成的内扩散控制；氢氧化钠熔融焙烧硅酸锌符合有固体产物层的扩散控制；氢氧化钠熔融焙烧氧化锌矿符合颗粒表面化学反应和固体产物层混合控制。(5). 硫酸铵和氢氧化钠的一次循环率分别达到95%和96%以上，制备得到了多形貌氧化锌、二氧化硅、氧化铅及碳酸钙产品。制备了氯化铅和碳酸锶产品。课题的研究可为符合我国矿产资源特点的低品位共生矿物的绿色化、高附加值综合利用提供参考。