某高镁低铁镍型红土镍矿石转底炉法还原提镍试验

某高镁低铁镍型红土镍矿石Fe、Ni品位分别为17.68%和1.62%,MgO含量为19.06%,镍主要以类质同象形式取代Fe、Mg存在于铁氧化物和硅酸盐矿物中,占比分别为39.65%和54.72%。为了确定该矿石的高效开发利用工艺,通过小型基础试验确定还原焙烧和磨选工艺参数,再在中径8 m的转底炉上进行还原焙烧中试试验。结果表明:试样采用煤基直接还原—水淬冷却—2阶段磨矿弱磁选工艺处理,在红土镍矿、石灰石、TN的质量配比为100∶10∶3,按碳氧物质的量之比1.2配入无烟煤,还原焙烧温度为1 280℃,还原焙烧时间为40 min,还原焙烧熟料水淬产品一段磨矿细度为-0.074 mm占83.31%,一段弱磁选磁场强度为190.98 k A/m,二段磨矿细度为-0.074 mm占97.43%,二段弱磁选磁场强度为127.32 kA/m的情况下,获得了Ni品位为5.63%、Fe品位为60.39%、Ni回收率为80.83%、Fe回收率为75.14%的镍铁粉;中径8 m的转底炉中试产品经磨选,获得了Ni品位为5.26%、Fe品位为59.20%、Ni回收率为80.84%、Fe回收率为74.98%的镍铁粉。该研究成果可作为工程化的依据,也为同类型红土镍矿石资源的高效开发利用提供了技术借鉴。

Experiment on Reduction and Extraction of Nickel from High-magnesium Low-iron Nickel Laterite by Rotary Hearth Furnace

The low-iron， low-nickel and high-magnesium nickel laterite ore was investigated， in which contains 17.68% iron， 1.62 nickel and 19.06% MgO， respectively. Nickel mainly replaces iron and magnesium and exists in the form of isomorphism in iron oxides and silicate minerals， accounting for 39.65% and 54.72%. To determine the high-efficiency development utilization process， small-scale basic tests were conducted to obtain the parameters of the reduction-roasting and grinding-separation process and pilot-scale test was carried out on a rotary hearth furnace with a pitch diameter of 8 m. The results showed that the sample was treated by coal-based direct reduction， water quenching and two-stage grinding and low-intensity magnetic separation. The mass ratio of laterite nickel ore， limestone and TN was 100∶10∶3， mole ratio of C to O was 1.2 (anthracite) ， the reduction time was lasted 40 min in the temporary of 1 280 ℃. The water-quenched calciation products at first stage grinding fineness of -0.074 mm accounting for 83.31%， and the magnetic field intensity of first stage low-intensity magnetic separation was 190.98 kA/m， second stage grinding fineness of -0.074 mm accounting for 97.43%， and the magnetic field intensity of second stage low-intensity magnetic separation was 127.32 kA/m. Under the optimal conditions， ferronickel powder product which contains 5.63% nickel and 60.39% iron with recovery of 80.83% and 75.14% can be obtained. The pilot product of the rotary hearth furnace was ground and separated. The obtained ferronickel powder product contains 5.26% nickel and 59.20% iron， while the recovery of nickel and iron were 80.84% and 74.98%， respectively. The research results can be used as the basis for engineering， and can also provide a technical reference for the efficient development and utilization of the same type of laterite nickel ore resources.