Neutral Leaching of Low-Grade Pyrolusite with High Silica Content     

郑建华罗红玉  田熙科王龙艳杨超  皮振邦 《中国地质大学学报(英文版)》2007,18(2):25-166,176

Leaching studies of low-grade pyrolusite, containing 11.84% Mn with high silicon, were carried out using sodium sulfite as a reductant in ammonium sulfate medium. Various process parameters including temperature, leaching time, solid-liquid ratio, quantity of ammonium sulfate, as well as the amount of reducing agent were studied in detail. The manganese extraction yield was the response of the process. Temperature and reagent concentration exerted the most important positive effect on the manganese extraction. The optimized conditions showed that when the amount of reducing agent was a stoichonmetric amount, over 90% manganese extraction and the lowest impurities were achieved, the amount of heavy metal impurities in the manganese leaching liquid was less than 5 mg/L, and almost no iron and aluminum were extracted in 3 mol/L ammonium sulfate concentration at 100 ℃ in 45 min.  相似文献   

温致变色材料微胶囊化研究   总被引：5，自引：0，他引：5  

袁曦明  郑建华等 《地球科学》2002,27(1):46-49

温致变色材料的应用通常受强酸性、强碱性及环境杂质污染等因素的影响，以酸碱指示剂和pH值变化的熔化性化合物为变色心材的微胶囊化实验条件，探讨了微胶囊化机理。这类变色材料的微胶囊化技术将促进其应用研究。  相似文献   

高淳台YRY-4钻孔分量应变观测数据 突变（阶跃）及异常特征分析          下载免费PDF全文

侯跃伟  郑建华  夏孝田 《地震科学进展》2018,(5):20-27

利用2012—2016年江苏省南京市高淳台钻孔应变观测数据出现的8次突变（阶跃）事件,通过对其突变形态特征、阶跃幅度、持续时间及异常性质进行分析,并结合地震实例探讨钻孔应变与地震前兆异常机理之间的关系。   相似文献   

改进Tamura纹理特征的图像检索方法     

郝玉保  王仁礼  马军  苏斌  郑建华 《测绘科学》2010,35(4):136-138,176

针对Tamura方向度纹理特征计算时直方图峰值难以确定的问题,本文提出了采用改造后的旋转不变边缘方向直方图代替方向度纹理特征;针对粗糙度纹理特征不能充分反映图像上纹理基元尺寸的大小分布的问题,提出了采用粗糙度直方图代替粗糙度的特征表达方式。实验表明,改进后的Tamura纹理特征易于获取,包含图像更多的信息,显著地提高了检索性能。  相似文献