(1. 中南大學(xué) 冶金科學(xué)與工程學(xué)院，長沙410083；
2. 中南大學(xué) 難冶有色金屬資源高效利用國家工程實(shí)驗(yàn)室，長沙 410083)
摘 要: 為了查明鋁針鐵礦含量高的紅土型鋁土礦拜耳法溶出過程中氧化鋁溶出率低的原因，研究針鐵礦在溶出過程中的轉(zhuǎn)化規(guī)律及其對(duì)氧化鋁溶出率的影響。結(jié)果表明：在溶出溫度為110~240 ℃時(shí)，該類型鋁土礦中的鋁針鐵礦基本不發(fā)生轉(zhuǎn)化，其中的氧化鋁難以溶出；提高溶出溫度到260 ℃或在240 ℃左右溶出時(shí)，添加干礦石量3%的石灰可促使鋁針鐵礦轉(zhuǎn)化為赤鐵礦，且氧化鋁的溶出率隨著針鐵礦轉(zhuǎn)化程度的增加而提高。加入非鈣質(zhì)添加劑也可以促使鋁針鐵礦在溶出過程發(fā)生結(jié)構(gòu)轉(zhuǎn)變，且氧化鋁幾乎完全參與反應(yīng)，從而說明此類鋁土礦中鋁針鐵礦在溶出過程中難以轉(zhuǎn)變是紅土型鋁土礦中氧化鋁溶出率低的重要原因。
關(guān)鍵字: 三水鋁石礦；高鐵；溶出；鋁針鐵礦
（1. School of Metallurgical Science and Engineering, Central South University, Changsha 410083, China;
2. National Engineering Laboratory for Efficient Utilization of Refractory Non-ferrous Metals）
Abstract:The transformation law of goethite and its effect on the alumina recovery were investigated in order to determine the reason of low alumina recovery in Bayer digestion process of gibbsitic bauxite with high alumogoethite content. The results show that the goethite present in this kind of bauxite has no obvious change in the digestion temperature range of 110 ℃ to 240 ℃ with low alumina recovery. And alumogoethite can be transformed to hematite by increasing digestion temperature to 260 ℃ or adding lime of 3% of dry ores added at about 240 ℃, and the alumina digestion rate increases with the increase of the goethite conversion degree. Adding non-calcareous additives in the re-digestion process of red mud containing goethite can promote the structure transformation of alumogoethite and thus alumina almost reacts completely. The transition of alumogoethite into other forms in Bayer digestion process is important for alumina recovery for lateritic bauxite.
Key words: gibbsitic bauxite; high-iron; digestion; alumogoethite
