【作者】 李青刚；

【导师】 张启修；

【作者基本信息】 中南大学 ， 有色金属冶金， 2010， 博士

【摘要】 镍钼矿是我国特有的一种多金属复杂矿产资源,但因相对落后的开发技术及处理工艺,造成资源的极大浪费和严重的环境污染问题。本文根据镍钼矿资源特点及开发现状,首次提出了次氯酸钠(氯气)浸出全湿法和一次焙烧-碱浸法从镍钼矿中制取钼酸铵两种全新工艺路线,主要研究内容包括镍钼矿一次焙烧、焙砂碱浸、次氯酸钠浸出、氯气浸出、离子交换法从低浓度钼酸钠溶液中吸附钼、D314树脂吸附钼的平衡和动力学、离子交换法从钼酸铵溶液中去除微量钒、镍钼矿生产钼酸铵工艺设计等。研究成果在国内得到广泛应用,首次从镍钼矿中得到了符合国标(GB3460-82)的钼酸铵产品,极大地提高了镍钼矿开发金属回收率,降低了镍钼矿开发工艺过程中的三废排放,使镍钼矿开发领域整体工艺技术水平上了一个台阶。主要研究结果如下：为了减少传统镍钼矿多次焙烧-破碎工艺过程产生的巨大粉尘排放量,提出了镍钼矿一次焙烧-碱浸实验方案,考察了焙烧温度、焙烧时间、浸出温度、浸出时间、浸出液固比、氢氧化钠浓度等因素对钼浸出率的影响,实验结果显示,在最佳条件下,钼的浸出率可达到97%以上。为了彻底消除传统镍钼矿焙烧工艺过程产生的粉尘和S02烟气污染,提出了次氯酸钠浸出镍钼矿实验方案,考察了温度、次氯酸钠浓度、液固比、粒度、氢氧化钠加入量、碳酸钠加入量、浸出时间、终点pH值等条件对次氯酸钠浸出钼的影响,结果显示,在最佳条件下,钼的浸出率可达到98%。进一步的研究证明,次氯酸钠可选择性浸出镍钼矿中的钼,选择系数最高可达到3.5。首次提出了氯气浸出镍钼矿方法,并在自制的设备中进行了氯气浸出实验,考察了温度、NaOH加入量、终点pH值、镍钼矿粒度、液固比和通C12速度等因素对钼浸出率的影响,结果显示,在最佳条件下,钼的浸出率最高可达96%以上,浸出液含钼6-12g／L,pH8-9。经过树脂筛选实验,发现D314是一种最佳的从低浓度弱酸性含钼溶液中吸附钼的离子交换树脂；通过固定床实验,考察了料液pH值、浓度、吸附接触时间等因素对D314树脂吸附钼的影响,结果显示,D314树脂对钼的吸附容量远高于强碱性阴离子交换树脂,也明显高于其他弱碱性阴离子交换树脂；负钼D314树脂用10%的氨水解吸,可得到含钼120g·l-1以上的钼酸铵溶液。首次进行了D314树脂吸附钼的平衡和动力学研究,实验结果显示,交换反应240分钟基本达到平衡,pH值为3.5时,钼的吸附分配比最大达到69411,饱和吸附容量为292.30mg／mL湿树脂；对D314树脂吸附钼的饱和吸附容量和钼酸根在水溶液中的赋存形态进行分析和计算,得出钼以Mo40132-形态被树脂吸附；D314树脂吸附钼过程控制步骤为粒扩散步骤(PDF),表观活化能E为27.30kJ／mol。首次发现钒对钼酸铵质量的影响现象,创新性地提出螯合树脂去除钼酸铵溶液中微量钒的方法。搅拌试验结果显示,螯合离子交换树脂可以选择性吸附钼酸铵溶液中的钒,其中,DDAS、CUW和CW-2螯合树脂对钒(V)的吸附性能优于其他螯合离子交换树脂；通过固定床离子交换试验,考察了温度、溶液pH值、吸附接触时间等因素对除钒的影响,结果显示,在最佳条件下,DDAS、CUW和CW-2螯合树脂除钒率可达到99.5%以上,而钼的损失率小于0.27%,钒钼分离系数分别达到了126172、108097和105209；根据螯合树脂结构及钼酸铵溶液中微量钒存在形态,首次提出了螯合树脂吸附钒的络合反应机理。根据研究成果,设计了“镍钼矿次氯酸钠浸出-离子交换富集转型-解吸液净化-离子交换除钒-酸沉-四钼酸铵”和“一次焙烧-碱浸-离子交换富集转型-解吸液净化-离子交换除钒-酸沉-四钼酸铵”两条全新的镍钼矿制取钼酸铵工艺流程,这两条新工艺在十余家工厂得到成功应用,取得了显著的经济和环境效益。更多还原

【Abstract】 Ni-Mo ore is a complicated multi-metal mineral resource which is specific to China. The low-level technics of traditional extracting process has made huge waste of resources and grievous pollution to the local environment in exploiting of Ni-Mo ore. According to the property of Ni-Mo ore and present exploiting process, experimental processes of "entire hydrometallurgical process of leaching Ni-Mo ore with sodium hypochlorite(or Cl2)" and "one step roasting-calcine leaching with NaOH" were put forward for the first time. The study mainly focused on one step roasting, leaching of Ni-Mo calcine with NaOH, leaching of Ni-Mo ore with sodium hypochlorite, leaching of Ni-Mo ore with Cl2, Mo adsorption by ion exchange from low concentration solution, equilibrium and kinetics of Mo adsorption with D314 resin, removal of vanadium from ammonium molybdate solution by ion exchange, processing design of ammonium molybdate production from Ni-Mo ore. The achievement had been widely applied and high quality product of ammonium molybdate was obtained firstly from Ni-Mo ore which is in accordance with the standard of GB3460-82 for the first time, metal recovery was greatly improved, and the release of pollutant was reduced greatly. Main experimental results are as follows:In order to reduce discharge of powder in traditional process, "one step roasting-leaching of calcine with NaOH" was put forward. The effects of roasting temperature, roasting time, leaching temperature, leaching time, L/S of leaching, consumption of NaOH etc on leaching ratio of Mo from Ni-Mo calcine had been investigated. The experimental results show that leaching ratio was above 97% at the optimal condition.In order to avoid the release of powder and SO2, "entire hydrometallurgical process of leaching of Ni-Mo ore with sodium hypochlorite(or Cl2)" was put forward for first time. The effects of leaching temperature, concentration of NaClO, L/S of leaching, particle size of Ni-Mo ore, consumption of NaOH and Na2CO3, leaching time, and end pH etc on leaching ratio of Mo from Ni-Mo ore had been investigated. The experimental results show that leaching ratio of above 98% was obtained at the optimal condition. Test result also proved that NaCIO could selectively leach Mo from Ni-Mo ore, and selective coefficient reached 3.5.The test of leaching by Cl2 was put forward for the first time and carried out in self-made leaching vessel. The effects of temperature, consumption of NaOH, end pH, particle size of Ni-Mo ore, and L/S of leaching, and add velocity of Cl2 etc on leaching ratio of Mo from Ni-Mo ore was investigated. The experimental results show that leaching ratio of Mo above 96% was obtained at the optimal condition, the Mo concentration of leaching solution is about 6-12g/L, pH is 8-9.The results of selecting test of resin show that D314 resin is the best to adsorb Mo from weak acidic solution. Effects of pH of solution, concentration, and contact time of ion exchange on adsorption capability of Mo were investigated with fixed bed. The experimental results show that work adsorption capability of D314 resin to Mo was above 160mg/L at optimal conditions. The laden resin was desorbed by 10% ammonia and obtained above 120g/L Mo concentration of desorbed solution.The investigation of equilibrium and kinetics with D314 resin absorbing Mo was carried out for the first time. The experimental results show that adsorbed equilibrium time is about 240 minutes; When pH of solution is 3.5, saturation adsorption is 292.30mg/mL, distribution ratio is higher than 69411; by calculation of saturation adsorption of Mo and analysis of the form of molybdate in solution, molybdenum could be adsorbed by D314 through Mo4O132- from solution; Reaction control step of ion exchange is PDF, and the apparent activation energy is 27.30KJ/mol.The project that V(V) removal with chelate resins from ammonium molybdate solution is advanced for the first time. The experimental results show that chelate resins could adsorb vanadium preferentially from ammonium molybdate solution, but hardly adsorb Mo. Results of selecting resin show that DAS, CUW and CW-2 resins have higher adsorption capacity to vanadium than others. Effects of temperature, pH and adsorbing time to removal of vanadium were investigated, experimental results in fixed bed show that more than 99.5% of V(Ⅴ) can be adsorbed, but adsorbing ratio of Mo(Ⅵ) is less than 0.27%, separation coefficient of vanadium and molybdenum reached 126172,108097 and 105209 respectively at optimal conditions. According to the structure of chelate resins and the form of V(Ⅴ) in ammonium molybdate solution, mechanism of adsorbing V(Ⅴ) with chelate resin in ammonium molybdate solution was advanced for first time.According to the results achieved, two new processing flows of production ammonium molybdate from Ni-Mo ore were put forward, which are "leaching by NaClO-enrichment and transformation by ion exchange-purifying-removal of vanadium by ion-exchange-crystallization of ammonium molybdate by acidification" and "one step roasting-leaching by NaOH-enrichment and transformation by ion exchange-purifying-removal of vanadium by ion-exchange-crystallization of ammonium molybdate by acidification". The two processes succeeded in industrialization, and obtained enormous economic profit and environment protecting efficiency.更多还原