巴彦乌拉铀矿地浸过程中含矿层化学堵塞机理研究

发布时间：2018-04-12 10:37

本文选题：巴彦乌拉铀矿床 + 地浸过程　；参考：《东华理工大学》2017年硕士论文

【摘要】：巴彦乌拉矿铀床是我国在内蒙古二连盆地开发的第一个铀矿床,也是继新疆伊犁盆地后又一采用酸法地浸的铀矿山,该矿床尽管矿石铀品位较低、含矿层厚度较大,但含矿层渗透性较好,有利于地浸开采,具有良好开发前景。随着生产系统的运行,逐渐出现注液孔注液压力增大,即含矿层出现化学堵塞问题。本文针对含矿层堵塞问题,在分析含矿层矿物特征的基础上,根据浸出液化学成分,运用地球化学模式程序(PHREEQC)对浸出液—矿物平衡进行了模拟,确定了堵塞矿物类型,分析含矿层化学堵塞形成原因与形成条件,以溶浸液及浸出液离子浓度变化为约束条件,建立了溶浸液—矿物相互作用模型,模拟溶浸液与矿物相互作用过程,计算了矿物堵塞量与体积,对注液流量与孔隙率下降进行了对比,在此基础上揭示了含矿层化学堵塞机理。研究结果表明,巴彦乌拉矿床含矿层黄铁矿、碳酸钙含量相对较高,当高矿化度的强酸性溶浸液注入含矿层后,溶解了黄铁矿与碳酸钙,使溶液中Ca2+、Fe3+浓度大幅提高,特别是在氧化条件下,超过Ca2+、Fe3+平衡浓度边界值,即其浓度反应条件指数大于0,产生石膏、铁矿物沉淀,充填矿层孔隙,使孔隙率下降,导致渗透性能降低,注液压力增大,造成含矿层化学堵塞。本次模拟结果与矿床实际堵塞情况相吻合,认为采用平衡模拟与溶浸液—矿物相互作用模拟结合探讨含矿层化学堵塞机理是有效可行的。
[Abstract]:The uranium deposit of Bayan Wula deposit is the first uranium deposit developed in Erlian basin of Inner Mongolia in China. It is also a uranium ore mountain leached in situ by acid method after the Yili basin in Xinjiang. Although the uranium grade of ore is low, the ore-bearing strata are thick.But the permeability of ore-bearing bed is good, which is favorable to in situ leaching mining and has a good development prospect.With the operation of production system, the pressure of liquid injection hole increases gradually, that is, chemical blockage occurs in ore-bearing bed.In this paper, based on the analysis of mineral characteristics of ore-bearing beds, the leaching liquid-mineral balance is simulated by using the geochemical model program PHREEQC on the basis of the chemical composition of leaching fluids, and the types of blocked minerals are determined.The reason and condition of chemical clogging of ore-bearing bed are analyzed. With the change of ion concentration of leaching solution and leachate as the constraint condition, the model of leaching liquid-mineral interaction is established, and the process of interaction between leaching solution and mineral is simulated.The amount and volume of mineral plugging were calculated, and the decrease of injection flow rate and porosity were compared, and the mechanism of chemical plugging of ore-bearing beds was revealed.The results show that the ore layer pyrite and calcium carbonate content are relatively high in Bayan Wula deposit. When the strong acid leaching solution with high mineralization degree is injected into the ore bearing layer, the pyrite and calcium carbonate are dissolved, and the concentration of Ca2 + Fe 3 in the solution is greatly increased.Especially under oxidation condition, when the boundary value of equilibrium concentration of Ca2 + Fe3 is exceeded, that is, the reaction condition index of concentration is greater than 0, gypsum, iron mineral precipitate, filling pore of ore bed are produced, the porosity decreases, the permeability decreases and the injection pressure increases.Causing chemical blockages in ore-bearing beds.The results of this simulation are in agreement with the actual plugging of ore deposits. It is considered that it is effective and feasible to study the chemical plugging mechanism of ore-bearing beds by means of equilibrium simulation and leaching liquid-mineral interaction simulation.
【学位授予单位】：东华理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TD868

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