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市政排水工程质量的影响因素是多方面的,既有客观因素也有主观因素,而施工管理无疑是非常重要的一个因素。本文针对排水工程施工中的几个阶段的管理工作进行了阐述。 相似文献
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一、概况 我矿属硫酸钠型矿盐,原卤含硝37g/1左右。一九六九年建矿以来,一直采用冷法提取原卤中的芒硝。由于当时冷冻提硝工艺、设备很不成熟,到一九七九年我矿无水硝年产量仍未突破一万吨(设计3万吨/年)。七九年芒硝产出率仅为26.79%。而且产品质量差,主含量只能达到95%,为数不多的产品也无人问津。为了解决产品质量差、产 相似文献
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The enrichment of Ni from a low-grade saprolitic laterite ore,which has been pre-treated by high pressure grinding roller(HPGR) to be 74% passing 0.074 mm and contains 0.92% Ni,18.47% Fe,10.61% MgO and 42.27% SiO2,was conducted by using pelletizing,rotary kiln reduction and magnetic separation process on a semi industrial scale,and the effects of reduction duration,mass ratio of coal to pellets(C/P),the types of magnetic separator,the sections of grinding-separation and the grinding fineness on the recovery of Ni and Fe were examined.It is shown that nickel concentrate containing 3.13 % Ni and 59.20 % Fe was achieved at recoveries of 84.36 % and 71.51% for Ni and Fe,respectively under the following conditions:reducing at (1120±40) ℃ for 120 min,C/P being 1.0,wet grinding of reduced pellets up to 70%-87% passing 0.074 mm and a magnetic field intensity of 238.8 kA/m during the first section of grinding-magnetic separation,and a grinding fineness of 84%-91% passing 0.045 mm and a magnetic intensity of 39.8 kA/m during the second section of grinding-magnetic separation.The enriched Ni containing concentrate has a low content of S and P,and can be used for further processing to produce high-grade ferronickel alloy. 相似文献
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选择性还原-磁选回收镍渣中的有价金属 总被引:2,自引:0,他引:2
采用选择性还原-磁选工艺富集某镍渣中的镍、铜,通过控制还原过程参数实现选择性还原。结果表明:添加熔剂并适当提高渣料的碱度(CaO与SiO2质量比)有助于镍、铜的富集;对碱度0.15、还原温度1200℃、还原时间20 min、内配煤量5%(质量分数)的优化条件下得到的还原样品,通过磨矿-磁选获得镍、铜、铁品位分别为3.25%、1.20%、75.26%的精矿,镍、铜、铁的回收率分别为82.20%、80.00%、42.17%,实现了镍、铜相对于铁的选择性富集;选择性还原-磁选没有显著降低S、P的含量,两者在工艺过程中的行为需要进一步研究。 相似文献
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