贵州省六枝地区某黏土型锂矿物的工艺矿物学研究

艾光华 邱永宏

(1.江西理工大学 资源与环境工程学院，江西 赣州 341000；2.江西钨佩克矿业有限公司，江西 赣州 341000)

锂资源是重要的新兴产业资源，被誉为“金属新贵”、“能源之星”、“21世纪的能源金属”，是发展新能源、新材料的重要金属资源。锂矿一般来说有3种存在形式，分别是盐湖型(卤水型锂)、伟晶岩类型(矿物型锂)、沉积岩型(黏土型锂矿)，3种锂矿藏分别占全球锂资源总量的58%、26%和7%，目前工艺应用最广的是矿物型锂矿(矿物型的锂矿石有锂辉石、锂云母、叶长石、锂霞石、锂磷铝石等)[1，2]。与盐湖型和矿物型相比，黏土型锂丰度更低，目前还未实现大规模商业开采，全球黏土型锂资源尚处开发期。黏土型锂矿的赋矿地质体为黏土层，主要分布在美国、墨西哥、塞尔维亚等国家以及中国西南地区，根据成因不同，黏土型锂矿可分为火山岩黏土型锂矿、碳酸盐黏土型锂矿和贾达尔锂型矿[1，3，4]。为充分开发利用锂资源，本文通过扫描电子显微镜、MLA矿物自动分析仪、X射线衍射分析仪等对贵州六枝某黏土型锂矿进行工艺矿物学研究，以期能够明晰该矿石的物质成分、矿物组成、矿石的结构和构造，为制定该黏土型锂矿的选矿提取工艺和开发利用提供矿物学依据和支撑。

1 矿石组成

原矿中主要有价元素为锂，Li2O的含量为0.56%，属于低品位的锂黏土矿，其他主要的含量分别是Al2O3为28.34%、SiO2为32.99 %，CaO为11.54%。原矿的主要化学成分见表 1。

对原矿矿石的XRD图进行解谱分析的结果表明，矿石的物相组成主要以锂绿泥石、伊利石、方解石为主，少量石英、黄铁矿、石膏和迪凯石。

MLA分析结果见表2。由表2可知，锂矿物为锂绿泥石，硫化物以黄铁矿为主，脉石矿物以伊利石、石英、方解石为主。

表2 矿石矿物组成及含量

2 主要矿物特征

2.1 锂绿泥石

该矿石中锂绿泥石常普遍含铁、硫、钾、钙、镁等杂质，个别含钠、铬等杂质。矿石中锂绿泥石常呈微细粒鳞片状集合体，嵌布粒度细微，常呈胶结物包裹方解石、石英、黄铁矿等矿物中(图1～4)，少数锂绿泥石常呈微细粒鳞片状包裹在方解石和石膏中(图5～6)。

图1 锂绿泥石(Cookeite)呈细小鳞片状集合体与伊利石(Illite)紧密连生，黏土矿物呈胶结物状包裹细粒石英(Quartz)、方解石(Calcite)和微细粒黄铁矿(Pyrite)Fig.1 Cookeite is closely associated with illite in a fine scale-like aggregate，and clay minerals are wrapped in fine quartz，calcite，and pyrite in the form of cements

图2 锂绿泥石(Cookeite)呈细小鳞片状集合体与伊利石(Illite)紧密连生，黏土矿物呈胶结物状包裹细粒石英(Quartz)、方解石(Calcite)和微细粒黄铁矿(Pyrite)和石膏(Gypsum)Fig.2 Cookeite is closely associated with illite in a fine scale like aggregate，and clay minerals are wrapped in fine quartz，calcite，and fine pyrite and gypsum in the form of cement

图3 锂绿泥石(Cookeite)呈细小鳞片状集合体与迪凯石(Dickite)紧密连生，黏土矿物呈胶结物状包裹细粒石英(Quartz)、方解石(Calcite)和微细粒草莓状黄铁矿(Pyrite)Fig.3 Cookeite is closely associated with dickite in a fine scale like aggregate，and clay minerals are wrapped in fine quartz，calcite，and fine strawberry like pyrite in the form of cement

图4 锂绿泥石(Cookeite)呈细小鳞片状集合体与伊利石(Illite)紧密连生，黏土矿物呈胶结物状包裹细粒石英(Quartz)、方解石(Calcite)和细粒草莓状黄铁矿(Pyrite)，内穿插条带状石膏(Gypsum)Fig.4 Cookeite is closely associated with illite in a fine scale-like aggregate，and clay minerals are wrapped in fine-grained quartz，calcite，and fine-grained strawberry-like pyrite in the form of cement，and gypsum is interposed inside

图5 锂绿泥石(Cookeite)呈细小鳞片状集合体包裹在石膏(Gypsum)，石膏中包裹微细粒自形晶黄铁矿(Pyrite)Fig.5 Cookeite is a fine scale like aggregate wrapped in gypsum，in which micro fine grained euhedral pyrite is wrapped

图6 锂绿泥石(Cookeite)呈细小鳞片状集合体包裹在方解石(Calcite)，方解石中包裹微细粒草莓状黄铁矿(Pyrite)Fig.6 Cookeite is a fine scale like aggregate wrapped in calcite，in which microcrystalline strawberry-like pyrite is wrapped

2.2 伊利石

矿石中伊利石常呈微细粒鳞片状集合体，嵌布粒度非常细微，常与锂绿泥石紧密连生，呈胶结物状包裹方解石、石英、 黄铁矿、石膏等矿物中(图7～10)。

图7 伊利石(Illite)呈细小鳞片状集合体与锂绿泥石(Cookeite)紧密连生，黏土矿物呈胶结物状包裹细粒石英(Quartz)、方解石(Calcite)和微细粒草莓状黄铁矿(Pyrite)，黏土矿物内穿插条带状石膏(Gypsum)Fig.7 Illite is closely associated with lithium chlorite in a fine scale-like aggregate，while clay minerals are wrapped in fine quartz，calcite，and fine strawberry-like pyrite in the form of cement，and clay minerals are interspersed with banded gypsum

图8 伊利石(Illite)呈细小鳞片状集合体与锂绿泥石(Cookeite)紧密连生，黏土矿物呈胶结物状包裹细粒石英(Quartz)、方解石(Calcite)和细脉状石膏(Gypsum)Fig.8 Illite is closely associated with lithium chlorite in a fine scale like aggregate，and clay minerals are wrapped in fine quartz，calcite，and gypsum in the form of cements

图9 伊利石(Illite)呈细小鳞片状集合体与锂绿泥石(Cookeite)紧密连生，黏土矿物呈胶结物状包裹细粒石英(Quartz)、方解石(Calcite)和细粒草莓状黄铁矿(Pyrite)Fig.9 Cookeite is closely associated with dickite in a fine scale like aggregate，and clay minerals are wrapped in fine quartz，calcite，and fine strawberry-like pyrite in the form of cement

图10 伊利石(Illite)呈细小鳞片状集合体与锂绿泥石(Cookeite)紧密连生，黏土矿物呈胶结物状包裹细粒石英(Quartz)、方解石(Calcite)Fig.10 Illite is closely associated with lithium chlorite in a fine scale like aggregate，and clay minerals are wrapped in fine quartz and calcite in the form of cement

图11 石英(Quartz)与伊利石(Illite)、锂绿泥石(Cookeite)连生，黏土矿物内包裹细粒至微细粒草莓状黄铁矿(Pyrite)Fig.11 Quartz is associated with illite and cookeite，and clay minerals are wrapped with fine to fine strawberry-like shaped pyrite

图12 石英(Quartz)与方解石(Calcite)、伊利石(Illite)、锂绿泥石(Cookeite)连生Fig.12 Quartz is associated with calcite，illite，and cookeite

图13 石英(Quartz)呈细粒至微细粒粒状包裹在伊利石(Illite)、锂绿泥石(Cookeite)形成的黏土矿物集合体中，黏土矿物内包裹微细粒草莓状黄铁矿(Pyrite)Fig.13 Quartz is wrapped in a clay mineral aggregate formed from illite and Cookeite in fine to fine grained form，and the clay mineral is wrapped in fine strawberry-like pyrite

图14 石英(Quartz)呈不规则粒状与方解石(Calcite)连生Fig.14 Quartz is associated with calcite in irregular granular form

2.3 石英

矿石中石英嵌布粒度较细，常与锂绿泥石、伊利石等黏土矿物连生，多数石英呈微细粒粒状包裹在黏土矿物中，少数石英与方解石连生(图 11～14)。

2.4 黄铁矿

该矿石中的黄铁矿多数呈草莓状或球状集合体，嵌布锂绿泥石和伊利石等黏土矿物中，其嵌布粒度细，少数黄铁矿呈粗粒至中粒半自形晶状与方解石、黏土矿物连生(图15～20)。

图15 黄铁矿(Pyrite)呈半自形晶单体颗粒Fig.15 Pyrite is a semi idiomorphic single crystal particle

图16 黄铁矿(Pyrite)呈草莓状集合体包裹在伊利石(Illite)、锂绿泥石(Cookeite)形成的黏土矿物中Fig.16 Pyrite is a strawberry-like aggregate wrapped in clay minerals formed from illite and cookeite

图17 黄铁矿(Pyrite)呈草莓状集合体与石膏(Gypsum)、伊利石(Illite)、锂绿泥石(Cookeite)连生Fig.17 Pyrite is a strawberry-like aggregate associated with gypsum，illite，and lithium chlorite

图18 黄铁矿(Pyrite)呈细粒草莓状集合体包裹在伊利石(Illite)、锂绿泥石(Cookeite)形成的黏土矿物中Fig.18 Pyrite is a fine strawberry-like aggregate wrapped in clay minerals formed from illite and cookeite

图19 微细粒黄铁矿(Pyrite)呈草莓状集合体包裹在伊利石(Illite)、锂绿泥石(Cookeite)形成的黏土矿物中，部分黄铁矿呈细粒五角十二面体自形晶包裹在黏土矿物中Fig.19 Microfine pyrite is wrapped in clay minerals formed by illite and Cookeite as strawberry-like aggregates，and some pyrite is wrapped in clay minerals as fine pentagonal dodecahedral idiomorphic crystals

图20 黄铁矿(Pyrite)呈草莓状集合体与石膏(Gypsum)和方解石(Calcite)连生，并被伊利石(Illite)、锂绿泥石(Cookeite)形成的黏土矿物集合体包裹Fig.20 Pyrite is a strawberry-like aggregate associated with gypsum and calcite，and is surrounded by clay mineral aggregates formed from illite and lithium chlorite

2.5 方解石

该矿石中的方解石嵌布粒度相对较粗，多数方解石呈菱面体自形至半自形晶与锂绿泥石、伊利石、石膏等黏土矿物连生，部分方解石呈细粒至微细粒形式包裹在锂绿泥石、伊利石等黏土矿物集合体中(图21～26)。

图21 粗粒方解石(Calcite)呈自形晶单体颗粒Fig.21 Coarse calcite is an idiomorphic single particle

图22 粗粒方解石(Calcite)与伊利石(Illite)、锂绿泥石(Cookeite)黏土矿物连生Fig.22 Coarse calcite is associated with illite and Cookeite clay minerals

图23 粗粒方解石(Calcite)内包裹细粒锂绿泥石(Cookeite)和微细粒黄铁矿(Pyrite)Fig.23 Coarse calcite is surrounded by fine grained lithium chlorite(Cookeite)and fine grained pyrite(Pyrite)

图24 细粒方解石(Calcite)呈不规则粒状包裹在锂绿泥石(Cookeite)等黏土矿物中，黏土矿物内包裹细粒石英(Qaurtz)和微细粒草莓状黄铁矿(Pyrite)Fig.24 Fine calcite is wrapped in clay minerals such as lithium chlorite in irregular granular form，and the clay minerals are wrapped in fine quartz(Qaurtz)and fine strawberry-like pyrite(Pyrite)

图25 细粒方解石(Calcite)呈不规则粒状包裹在锂绿泥石(Cookeite)、伊利石(Illite)形成的黏土矿物集合体中，黏土矿物内包裹细粒石英(Qaurtz)和微细粒草莓状黄铁矿(Pyrite)Fig.25 Fine calcite is irregularly wrapped in clay mineral aggregates formed by Cookeite and Illite，and fine quartz and fine strawberry-like pyrite are wrapped in clay minerals

图26 方解石(Calcite)与伊利石(Illite)与锂绿泥石(Cookeite)形成黏土矿物集合体连生，黏土矿物内包裹细粒石英(Quartz)、方解石(Calcite)和微细粒草莓状黄铁矿(Pyrite)和条带状石膏(Gypsum)Fig.26 Calcite，illite，and cookeite form an aggregate of clay minerals，which are surrounded by fine quartz，calcite，and fine strawberry pyrite and gypsum

2.6 影响选矿的矿物学因素

伊利石是矿石中主要的脉石矿物，常呈微细粒鳞片状集合体，嵌布粒度非常细微，常与锂绿泥石紧密连生，呈胶结物状包裹方解石、石英、黄铁矿、石膏等矿物中；黄铁矿多数呈草莓状或球状集合体，嵌布锂绿泥石和伊利石等黏土矿物中，其嵌布粒度细，少数黄铁矿呈粗粒至中粒半自形晶状与方解石、黏土矿物连生。锂绿泥石矿石中主要的锂矿物，矿石中锂绿泥石常呈微细粒鳞片状集合体，嵌布粒度细微，常呈胶结物包裹方解石、石英、黄铁矿等矿物，少数锂绿泥石常呈微细粒鳞片状包裹在方解石和石膏中。

根据矿石性质特征，矿石中锂绿泥石多与黏土矿物等成分混杂，可选性差，且多与其他矿物呈紧密连生，难以通过物理选矿方法有效分离，很难通过物理选矿的方法富集。建议对矿石采用煅烧、浸出等方案提取矿石中的锂元素。

3 结论

1)贵州六枝地区黏土型锂矿物矿石中的主要有价元素为锂，含量为0.56%，主要有用矿物包括锂绿泥石和黄铁矿，脉石矿物以伊利石、石英、方解石为主。

2)矿石中锂绿泥石常呈微细粒鳞片状集合体，嵌布粒度细微，常呈胶结物包裹伊利石、方解石、石英、黄铁矿等矿物，少数锂绿泥石常呈微细粒鳞片状包裹在方解石和石膏中，可选性差，且多与其他矿物呈紧密连生，难以通过物理选矿方法有效分离。建议对矿石采用煅烧、浸出等冶金方法提取矿石中的锂。