Comparative study of alkali roasting and leaching of chromite ores and titaniferous minerals
Comparative study of alkali roasting and leaching of chromite ores and titaniferous minerals
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DOI：
10.1016/j.hydromet.2015.08.002
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发表时间：
2016-10-01
期刊：
影响因子：
4.7
通讯作者：
Jha, Animesh
中科院分区：
文献类型：
--
作者：
Parirenyatwa, Stephen;Escudero-Castejon, Lidia;Jha, Animesh
钛和铬氧化物的提取可以通过在高温下用碱焙烧，然后用水和有机酸浸出来实现。本研究以氢氧化钠和氢氧化钾为碱，焙烧铬铁矿和钛精矿。从焙烧工艺设计的角度对焙烧过程进行了热力学分析。铬铁矿和含钛矿物的样品在氧化气氛中用氢氧化钠和氢氧化钾在400摄氏度-1000摄氏度的温度范围内焙烧。对焙烧后的铬铁矿和钛铁矿样品进行深加工，分别从反应后的铬铁矿中提取水溶性Na2CrO4，从含钛矿物中提纯二氧化钛。在400℃下用氢氧化钠焙烧和二次浸出得到的二氧化钛纯度为49.2wt.%，而用氢氧化钾焙烧得到的纯度为54.5wt.%。在1000℃焙烧2 h，水和有机酸二次浸出得到的二氧化钛纯度最高可达84wt，低温下(400℃)KOH焙烧的铬铁矿的铬回收率高于NaOH焙烧的铬铁矿。然而，在高温下(700摄氏度和1000摄氏度)，用两种氢氧化物焙烧时，铬的回收率相似。铬铁矿在1000℃下用氢氧化钠和氢氧化钾焙烧2 h，加水浸出，铬浸出率可达95%左右。(C)2015年提交人。爱思唯尔出版公司(Elsevier B.V.)
Extraction of titanium and chromium oxides may be achieved via roasting the respective minerals with alkali at high temperatures, followed by water and organic acid leaching. In this study, sodium and potassium hydroxides are used as alkali for roasting of chromite ores and ilmenite mineral concentrates. The thermodynamic analysis of the roasting process is discussed in terms of designing the process. Samples of chromite and titaniferous minerals were roasted with NaOH and KOH in a temperature range of 400 degrees C-1000 degrees C in an oxidising atmosphere. The roasted chromite and ilmenite samples were further processed in order to extract water-soluble Na2CrO4 from the reacted chromite and purify titanium dioxide from titaniferous minerals, respectively. The TiO2 purity obtained after roasting at 400 degrees C with NaOH and double leaching was 49.2 wt.%, whereas when using KOH the purity was 54.5 wt.%. The highest TiO2 purity obtained after roasting at 1000 degrees C for 2 h and double leaching with water and organic acids was 84 wt. At low temperature (400 degrees C) the recovery of chromium was higher for chromite roasted with KOH than for chromite roasted with NaOH. However, at high temperatures (700 degrees C and 1000 degrees C) chromium recoveries were similar when roasting with both hydroxides. Around 95% chromium extraction yield was achieved when chromite was roasted with sodium and potassium hydroxides at 1000 degrees C for 2 h and water leached. (C) 2015 The Authors. Published by Elsevier B.V.