浙江省衢州市上方镇重钙方解石矿工艺指标影响因素

重质碳酸钙的白度和色相值(Lab)是最重要的工业指标,但影响因素尚不清楚。本文通过扫描电镜、粉晶X射线衍射(XRD)和电感耦合等离子体发射光谱(ICP-OES)等分析手段,对浙江衢州上方镇的重钙方解矿石进行了研究,以期阐明重质碳酸钙白度和色相的影响因素。结果表明,矿石随研磨粒度的减小白度逐渐增加,在100~400目,白度呈快速上升趋势,超过400目,白度的上升趋势减缓,直至几乎不变。相较于青相矿石,红相矿石的方解石结晶程度高、颗粒大且均匀,杂质较少,化学成分较纯。而Fe3+含量与重钙产品白度和L值呈负相关,与a、b值呈正相关关系。综合研究认为,致色元素(Fe)含量的高低和原矿石的杂质含量、结晶程度均可能为重钙色相差异的主要原因,建议在方解石矿工业勘查中将白度指标测试的粒径统一为400目(38μm)。

A Study on Influencing Factors of Technological Mineralogy of Heavy Calcium Calcite Ores in the Shangfang Town,Quzhou City,Zhejiang Province

Whiteness and hue(Lab) values of heavy calcium carbonate are the most important industrial indicators for the industrial application of heavy calcium carbonate though their influencing factors are still unclear. In this paper, by conducting modern analytical methods including scanning electron microscope(SEM), powder crystal X-ray diffraction(XRD) and inductively coupled plasma emission spectroscopy(ICP-OES), we have analyzed heavy calcium calcite ore samples in the Shangfang Town, Quzhou City, Zhejiang Province in order to clarify influencing factors of the whiteness and hue values for heavy calcium carbonate. Experimental results show that whiteness values of ores at different grades are generally increased with the decrease of grinding particle sizes. Especially, from 100 to 400 mesh of grinding particle sizes, the whiteness values are sharply increased with a steep slope for the distribution curve. While the sizes are smaller than 400 mesh, the whiteness values are little smoothly increased with a flat slope for the distribution curve. Compared to ores of blue phase, calcites of red phase ores have better crystallinity, larger and more similar size, less impurity, and more consistent chemical compositions. The Fe3+ contents are negatively correlated with whiteness and L values of the heavy calcium product but are positively correlated with its a and b values. It is comprehensively concluded that the differences in hue values of heavy calcium carbonate could be mainly attributed to the contents of chromogenic elements(Fe), and the impurity and crystallinity of original ores. Additionally, it is recommended that the particle size of heavy calcium calcite should be modified to 400 mesh(38 μm) for the industrial exploration of calcite deposit.