Novel technology on preparation of double-layered pellets for sulfur and arsenic-bearing gold concentrates

Double-layered pellet （DLP） roasting is a novel pretreatment method for sulfur and arsenic-bearing gold concentrates. In this process, preparation of DLPs is a fundamental step which is required to produce DLPs with favorable mechanical strength and thermal stability. Studies were carried out to investigate the affecting factors and conditions on the preparation and properties of DLPs. The results show that moisture content has significant influence on DLPs preparation. With the increase of moisture content in the range of no more than 9.8%, drop resistance and compressive strength of green DLPs are raised and the pelletizing dynamics is improved accordingly. The optimum conditions are determined as moisture content of 9.8%, coating time of 14-16 min, drying temperature 〈80 ℃and drying gas velocity 〈1.2 m/s. When DLPs prepared under these conditions are roasted at 600 ℃ for 1 h, favorable removal and solidifying rates can be obtained, in which the removal rates of arsenic and sulfur are 94.38% and 82.55%, and the solidifying rates of arsenic and sulfur reach 99.62% and 99.79%, respectively. These results promise industrial application of DLP roasting.     

硅冶炼粉料冷压造块工艺研究

从粘结剂的选取出发, 对硅粉、石油焦粉和煤粉的混合料进行了冷压造块的试验研究。研究结果表明: 单一粘结剂的造块效果差, SDB和水玻璃的复合粘结剂造块效果好。当造块压力不低于35 MPa, 造块水分为6%～7%, 添加1%的SDB和3.5%的水玻璃, 得到的团块强度好。其湿块3 m落下强度大于1次, 干块3 m落下强度大于10次, 干块抗压强度大于700 N/cm²。干块在1 300 ℃高温下焙烧仍保持成块, 耐高温性好, 满足硅冶炼的要求。