(北京科技大學(xué) 土木與環(huán)境工程學(xué)院，北京 100083)
摘 要: 在較大Na2SO4用量范圍內(nèi)，研究Na2SO4對(duì)高鐵低鎳型紅土鎳礦選擇性還原焙燒的作用機(jī)理。結(jié)果表明：Na2SO4的作用隨其用量變化有本質(zhì)的區(qū)別；隨其用量增加，磁選鎳鐵產(chǎn)品中鎳的品位和回收率以及鎳鐵回收率差均先提高后降低，而鐵產(chǎn)率和回收率則是先降低后升高；當(dāng)Na2SO4用量為5%時(shí)，選擇性還原效果最佳；Na2SO4會(huì)損耗煤中的固定碳，減弱還原氣氛，使試樣中的鐵礦物還原為不具磁性的FeO；而當(dāng)Na2SO4過(guò)量時(shí)，會(huì)導(dǎo)致部分鐵礦物還原為含鎂磁鐵礦，造成鐵回收率呈現(xiàn)先降低后提高的變化規(guī)律，同時(shí)過(guò)量的Na2SO4還會(huì)生成多余的Na2S，與焙燒體系中的NiO和FeO發(fā)生反應(yīng)生成NiS和FeS，二者混熔生成(Ni,Fe)S，導(dǎo)致鎳的品位和回收率都降低。
關(guān)鍵字: 紅土鎳礦；選擇性還原焙燒；鎳鐵；Na2SO4
（School of Civil and Environment Engineering,University of Science and Technology Bejing, Beijing 100083, China）
Abstract:The mechanism of sodium sulphate in a large range of dosage on selective reduction roasting of high iron and low nickel laterite was studied. The results show that, the effect of sodium sulphate was fundamentally different as its dosage changes. With increasing dosage of sodium sulphate, in the ferronickel product, the magnetic separation, the content of nickel, the recovery of nickel and the difference between recovery of nickel and iron first improve and then decrease, while the yield and the recovery of iron first decrease, and then improve. When the dosage of sodium sulphate is 5%, selective reduction is the most significant. Sodium sulphate reacts with carbon in coal and weakens the reducing atmosphere, resulting in that iron minerals in the ore sample used are reduced to non-magnetic wustite. And when it is excessive, part of iron minerals are reduced to magnesioferrite. Those caused that the recovery of iron first decreases and then improves. Meanwhile, excessive sodium sulphate ill make excessive sodium sulphide, which reacts with nickel oxide and wustite, producing monosulfidic nickel and troilite. Both of them would mixed melt to (Ni,Fe)S, leading to decreasing about content and recovery of nickel.
Key words: laterite; selective reduction roasting; ferronickel; sodium sulphate
