胶磷矿伴生含钾页岩载钾矿物水云母"氧化-柱撑/离子交换法"脱钾过程的矿物学研究

Potassium mineral is the one of strategic mineral resources in shortage state in China. The research on the new theory and the new method about extracting-potassium from the hard-soluble potassium minerals is the key to solve the shortage state of potassium resource in China. The research object of the subject is the potassium-loading mineral hyromica existing in the potassium-containing shale associated with collophalite. Firstly, the new approach MLA was adopted for a basic research to the process mineralogy of raw ore and concentrated ore comprehensively and systematically. On this basis, "oxidation-pillared and cationexchange "method was put forward for exploring a new way to process of extracting-potassium from the hard-soluble potassium minerals. Through the study of the change rule of structural parameters of hyromica in the process of oxidation and the dynamics of extracting-potassium, Moreover, the study of the electrovalence compensation law of the structural unit layer of hyromica caused by oxidization, "Coulomb effects" in the process of oxidation and extracting-potassium of hyromica was expounded and proved at mineralogy angle. Through the study of the dependency rules between carbon atom number and (001) d-value in structural unit layer of hyromica, the general principles of choosing alkylammonium salts pillared-agent was established. Through the study of the movement rules of the hyromica structure layer before and after pillared, the mineral polymorphism transformation model was built. Through the study of the change rules of the bond length and the bond angle and coordination number, the "layer force" model of hyromica layer was established. Based on the above research findings, the "Spatial effects" theory about the influence of the cation exchange between Na+ and K+ to the dynamics of extracting-potassium by the modification with pillared in hyromica was expounded and proved at mineralogy angle. Research results can theoretically be used to guide the choice of the process such as the sorting and enrichment of hyromica in potassium-containing shale, the extracting-potassium, the subsequent chemical processing and so on.

钾矿属我国资源短缺的战略性矿产，对难溶性含钾矿物脱钾新理论、新方法的研究是解决我国钾资源短缺的关键。课题以胶磷矿伴生含钾页岩载钾矿物水云母作为研究对象，首先采用MLA新手段对其原矿及富集矿工艺矿物学进行全面系统的基础性研究，在此基础上，提出"氧化-柱撑/离子交换脱钾法"，为脱钾工艺探索一条新的途径。通过研究氧化脱钾动力学过程中水云母结构参数的变化规律以及结构单元层的电价补偿规律，从矿物学角度论证水云母氧化脱钾动力学过程的"库仑效应"。通过研究柱撑前后①碳原子数与（001）d值之间的相关性规律，建立选择烷基铵盐柱撑剂的一般原则；②云母结构层的移动规律，建立矿物多型转变模型；③键长和键角及其配位数的变化规律，建立'δ层间力'模型，从矿物学角度论证水云母柱撑插层修饰对Na+-K+阳离子交换脱钾动力学过程影响的"空间效应"。研究成果可以为含钾页岩的分选富集、脱钾及其后续化学加工等工艺提供理论指导。

通过对胶磷矿伴生含钾页岩进行研究，测定出了矿石的化学成分、各组分的赋存状态、含钾钒矿物的嵌布特征及其单体解离度。研究结果表明：K2O组分和V2O5组分主要以水云母矿存在；钒离子为三价，以类质同象形式处于云母层状结构中的八面体空隙间；云母类矿物大部分呈片状杂乱嵌布在石英质和其它脉石矿物中，一般介于0.01～0.04mm之间。.通过对宜昌胶磷矿伴生含钾页岩富集矿进行研究，测定出了矿石的化学成分、各组分的赋存状态、含钾矿物的嵌布特征及其单体解离度。研究结果表明：K2O主要以水云母矿存在，云母类矿物大部分呈片状杂乱嵌布在石英质和其它脉石矿物中，少量呈微细的包裹体嵌布在铁质矿物集合体中。.采用钡离子交换法，用盐酸做激化剂，成功地从含钾云母层间提取可溶性钾离子。实验得出最佳工艺条件：反应时间(t)3-4小时，反应温度(T)为45℃，初始BaCl2•2H2O浓度（CBa）为1.5mol/L。通过对同一反应时间不同CBa的提钾率（ψK）变化趋势研究以及FT-IR和XRD结构分析，对其离子交换机理进行了研究。并提出 “空位效应”和“半径效应”来解释层间距和红外吸收峰的同步分段变化。.利用氧化剂硝酸将云母结构八面体中的二价铁氧化成三价铁，从而改变硅氧四面体中非桥氧的价键分布。同时，利用这种“库仑效应”和类质同象置换原则，使用和钾离子半径相近的钡离子作为置换离子置换云母层间的钾离子。经过20小时的氧化/离子交换脱钾，有 96% 的钾离子被钡离子置换出来，云母原矿转变成水钡云母，其层间距d值由原来的1.0 nm增大到1.2 nm。.在氧化含铁黑云母的同时加入有机柱撑剂十八烷基三甲基氯化铵（STAC），撑开云母晶层，增大云母层层间距，从而增大云母结构层间距d（001）值，利用这种“空间效应”来减小离子交换的空间位阻，加速脱钾过程。利用氧化-柱撑/离子交换法，能将最大 98% 的钾离子从云母层层间置换出来，云母片层的层间距d（001）最大可以被撑开到4.0 nm。柱撑过程可以加速氧化/离子交换的反应速率。XRD和FTIR结果表明，硝酸钡加入量、反应时间、STAC用量均对STA+分子在柱撑云母层间的排列方式有着相类似的影响过程，STA+均先已单层倾斜排列转变到双层倾斜排列。