(中南大學(xué) 冶金與環(huán)境學(xué)院，長沙 410083)
摘 要: 采用氧化-水解法從高鐵硫酸鈷溶液中除鐵，再采用水熱法對除鐵渣進(jìn)行脫硫轉(zhuǎn)型成赤鐵礦的過程。考察雙氧水用量、pH值、溫度、晶種及添加劑對除鐵率、鈷損失率，除鐵渣粒度、形貌及漿液沉降速度的影響，以及水熱溫度、時間、NaOH濃度對除鐵渣水熱轉(zhuǎn)型成赤鐵礦中鐵、硫含量及物相和形貌的影響。結(jié)果表明：雙氧水用量1.5倍理論量、pH值2.6、反應(yīng)溫度70 ℃，在此條件下采用半連續(xù)-并加法反應(yīng)4 h，除鐵率達(dá)到99.68%，鈷損失率低至2.87%。添加Fe(OH)3晶種或PAM與PEG2000復(fù)配添加劑能大幅提高反應(yīng)后漿液的沉降速度。對除鐵渣進(jìn)行水熱轉(zhuǎn)型，升高溫度、延長時間、提高堿濃度均有利于無定型除鐵渣向赤鐵礦轉(zhuǎn)化。在水熱溫度230 ℃、水熱時間2 h、NaOH濃度40 g/L時，渣中物相全部轉(zhuǎn)化成赤鐵礦，鐵含量達(dá)65.63%，硫含量僅為0.014%。
關(guān)鍵字: 赤鐵礦；高鐵硫酸鈷溶液；氧化水解；除鐵；水熱轉(zhuǎn)型
（School of Metallurgy and Environment, Central South University, Changsha 410083, China）
Abstract:Iron removal from high-iron cobalt sulfate solution by oxidative hydrolysis, and subsequent hydrothermal conversion of the iron residue into hematite were investigated. The factors influencing iron removal rate, cobalt loss rate and slurry settling speed, such as hydrogen peroxide dosage, pH value, temperature, seeds and additives, were investigated. This study also elucidates the influences of temperature, duration, NaOH concentration on iron and sulfur content, phase and morphology on the treated residue during the hydrothermal conversion process. The results show that, under the optimal conditions of 1.2 times of theoretical amount of H2O2, pH of 2.6, temperature of 70 ℃ and time of 4 h, the iron removal rate can reach 99.68% and the cobalt loss rate is as low as 2.87%. The addition of Fe(OH)3 seeds, PAM and PEG2000 mixed additives can greatly increase the slurry settling performance. Raising temperature, prolonging time and increasing alkali concentration are beneficial to the conversion of amorphous iron hydroxide into hematite. When the hydrothermal temperature is 230 ℃, the hydrothermal duration is 2 h and the NaOH concentration is 40 g/L, the amorphous phase in the iron residue are completely converted into hematite, with iron and sulfur content of 65.63% and 0.014%, respectively.
Key words: hematite; high-iron cobalt sulfate solution; oxidative hydrolysis; iron removal; hydrothermal conversion
