中文摘要：

基于煤基深度还原技术,采用SEM和XRD等方法,考察了还原温度、还原时间及碳氧比的变化对海砂矿含石墨粉压块在还原过程中微观形貌的影响,并探讨了海砂矿还原体系中渣铁的分离聚合行为及金属矿物的还原效果,明确了海砂矿的微观还原机理。结果表明：在还原温度为1300℃、还原时间为30 min、碳氧比为1.1的条件下,球团的铁金属化率和抗压强度分别可达94.23%和243.3 N/个;还原温度升高和还原时间延长,产物的铁金属化率和抗压强度上升,内部形成更多的铁连晶和渣相连接,有利于提高压块的强度;合适的碳氧比可为海砂矿深度还原提供充足的还原剂,且不因石墨粉过剩而造成压块抗压强度下降;固态还原海砂矿过程中的物相转变过程为Fe3-xTixO4→Fe＋FeTi O3→Fe＋Fe2TiO5。

英文摘要：

According to the coal-based reduction technology, the effect of reduction temperature, curing time and C/Omolar ratio on the microstructure of the reduced marine placer-graphite briquettes were analyzed by using scanning electron mi-croscope （SEM） and X-ray diffraction （XRD）. Meanwhile, the separation and agglomeration behavior of iron slag as well asthe reduction results of metallic mineral were also discussed, and the micro-mechanism of reduction was clear. The results showthat the metallization rate and briquette strength could reach 94.23% and 243.3 N/P at reduction temperature 1 300 ℃ for 30minutes and w （C）/w （O） 1.1 ; Metallization rate and compress strength increased with reduction temperature and time, form-ing more iron joined crystal and slag bonding,which can increase the strength of the sample;Appropriate C/O ratio can providesufficient reductant during the deep reduction without residual graphite to threaten the compress strength. The phase-transitionin solid reduction of marine placer was summarized as Fe3_xTixOa--＋Fe＋FeTiO3--Fe＋Fe2TiOs.