稀有矿物锰方硼石的合成及其矿床地质意义

锰方硼石为稀有的锰氯硼酸盐(Mn3B7O13Cl)矿物, 首次发现于美国德克萨斯州钱伯斯郡盐丘回收的卤水中, 中国天津市蓟县赋存有世界上独一无二的锰方硼石矿床。采用五水平三因素(L25(53))的25组正交试验, 利用焙烧法人工合成锰方硼石, 得到锰方硼石的形成温度为250~400 ℃，弱酸性，高氯环境。实验条件下，最佳形成条件为400 ℃、C氯离子/C锰离子=2.5、pH=6。3种影响反应的因素中, 温度为主要因素。采用水热法在最优合成条件下得到了晶形比较完好的锰方硼石，平均粒度为600 nm。通过对钱伯斯郡盐丘和天津蓟县锰方硼石矿床的地质特征的分析讨论，认为蓟县锰方硼石矿床是海底热液成因，成矿温度低于400 ℃，并提出成矿模型。

Synthesis of the rare mineral chambersite and its ore deposit geological significance

Chambersite is a rare kind of manganese chlorine borate mineral(Mn3B7O13Cl),which was first discovered in brine recovered from salt pan,in Chambers,Texas,USA.Jixian chambersite deposit is the only independent ore deposit in the world.In this paper,chambersite was synthesized by the L25(53) orthogonal designation and it processed 25 groups of experiments by roasting method.The mineral was formed in 250-400 ℃,weak acid,high chloride environment.From the results,the best forming conditions are temperature 400 ℃,CCl-/CMn2+=2.5,and pH=6.In these three factors of influence,temperature is the main factor.Using the hydrothermal method,the synthesized chambersite has perfect crystal form and the average particle size is 600 nm.The discussion about geological features of Chambers salt dome and Jixian chambersite deposit lead to a conclusion that Jixian chambersite deposit metallogenic temperature is below 400 ℃ and the genesis of the deposit is closely related to submarine hydrothermal fluid.Finally,the ore-formation model was built up.