(1. 北京有色金屬研究總院 稀有金屬冶金與材料研究所，北京 100008；
2. 中國(guó)科學(xué)院 過程工程研究所 濕法冶金清潔生產(chǎn)技術(shù)國(guó)家工程實(shí)驗(yàn)室，北京100190；
3. 利達(dá)光電股份有限公司，南陽 473003)
摘 要: 針對(duì)鉻鐵礦氧化焙燒后期鉻轉(zhuǎn)化速率降低問題，以鉻鐵礦焙燒過程鉻轉(zhuǎn)化率70%的鉻渣為原料，分析鉻渣的物相和化學(xué)成分，深入研究鉻渣焙燒過程中溫度、時(shí)間、Na2CO3和CaCO3 等對(duì)鉻渣中鉻轉(zhuǎn)化率的影響，探討提高鉻鐵礦氧化焙燒后期鉻轉(zhuǎn)化率的機(jī)理。結(jié)果表明：鉻渣主相為MgCr0.4Fe1.6O4尖晶石，副相為NaSiAlO4和Mg1.5Na9Si12Al12O48等鈉硅酸鹽、硅鋁酸鹽相；在與Na2CO3進(jìn)行氧化焙燒反應(yīng)過程中鉻轉(zhuǎn)化率僅為50%~60%，鈉硅酸鹽、硅鋁酸鹽等相的存在導(dǎo)致Na+的利用率降低，造成鉻渣中的鉻轉(zhuǎn)化困難；Ca的引入置換了鉻渣中副相的Na，鉻轉(zhuǎn)化率提高到84.7%，生成了高熔點(diǎn)的Ca2Fe1.2Mg0.4Si0.4O5硅酸鈣鹽等相，增大了焙燒過程中Na+濃度，促進(jìn)了鉻的轉(zhuǎn)化，提高了焙燒后期鉻的轉(zhuǎn)化率。
關(guān)鍵字: 鉻渣；焙燒；置換；Na+濃度；再氧化
（1. Division of Rare Metal Materials and Metallurgy, General Research Institute for Non-Ferrous Metals, Beijing 100008, China;
2. National Engineering Laboratory for Hydrometallurgical Cleaner Production Technology,
Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, China;
3. Lida Photoelectric Co., Ltd., Nanyang 473003, China）
Abstract:Based on the conversion rate of trivalent chromium at the late stages of the chromite lime-free roasting, Na2CO3 roasting of the chromium residues obtained by roasting the chromite ore with Na2CO3 with the conversion rate of 70% was used as raw materials. The phases and chemical composition of chromium residues were analyzed firstly, the effects of roasting process conditions such as roasting time, roasting temperature and the amount of Na2CO3 and CaCO3 addition, on the Cr conversion rate were further investigated. The mechanism of reoxidation of trivalent chromium at the late stages of roasting process was studied. The results show that the main phase of the chromium residues is MgCr0.4Fe1.6O4 spinel, and some sodium silicate and silicon aluminate phases, such as NaSiAlO4 and Mg1.5Na9Si12Al12O48 also exist in the chromium residues. During the roasting process of chromium residues reacting with Na2CO3, the conversion rate of trivalent chromium of chromium residues is only 50%-60%, due to low utilization of Na+ that resulted from the formation of sodium silicate and sodium silicon aluminate phases. The conversion rate of trivalent chromium increases to 84.7% when the CaCO3 is added into the roasting process of chromium residues, the sodium silicate and silicon aluminate reacts with Ca to generate high melting point calcium silicate salt phases, such as Ca2Fe1.2Mg0.4Si0.4O5. Therefore, the concentration of Na+ is improved and the chromium transformation is promoted, and the conversion rate of trivalent chromium increases at the late stages of roasting process.
Key words: chromium residue; roasting; replacement; Na+ concentration; re-oxidation
