DOC《从含铟硫酸钙渣中回收铟》

从含铟硫酸钙渣中回收铟 陈先友,朱北平,姚应雄,杨成武,王邦伟 (云南华联锌铟股份有限公司,云南文山 663701) 摘要:对高铁闪锌矿湿法炼锌过程中产出的含铟硫酸钙渣开展了一段酸浸―浸出液铁粉还原―还原液净化预处理―萃取―反萃试验研究,实现了铟与其他杂质元素的分离与高效回收.

含铟硫酸钙渣在终酸70 g/L、温度80 ℃、液固比4U

1、时间2 h的条件下进行一段酸浸,铟浸出率98%以上;

用铁粉将浸出液中的Fe3+还原为Fe2+,铁粉过量系数1.5,Fe3+还原率在98%以上;

添加8 g/L的活性炭对还原液进行净化预处理;

用30%的P204在酸度70 g/L、相比A/O=4U

1、混合时间3 min、温度45 ℃的条件下对净化液进行四级逆流萃取,铟萃取率达到97.5%以上,萃余液含铟小于4 mg/L;

负载有机相用6 mol/L的盐酸,相比A/O=1U12,经过四级连续反萃,反萃液铟浓度可富集至70 g/L以上. 关键词:含铟硫酸钙渣;

浸出;

还原;

铟;

萃取;

反萃 中图分类号:TF843.1 文献标志码:A 文章编号:1007-7545(2017)12-0000-00 Indium Recovery from Indium-bearing Calcium Sulfate Slag CHEN Xian-you, ZHU Bei-ping, YAO Ying-xiong, YANG Cheng-wu, WANG Bang-wei (Yunnan Hualian Zinc Indium Co., Ltd., Wenshan 663701, Yunnan, China) Abstract:Indium was recovered from indium-bearing calcium sulfate slag by acid leaching, lixivium reduction with iron powder, pretreatment of reduction solution, solvent extraction of indium, and indium stripping. Acidic leaching rate of In is 98% above under conditions of terminal acidity of

70 g/L, temperature of

80 ℃, L/S=4U1, and leaching time of

2 h. Fe3+ reduction rate is 98% above upon iron powder excess coefficient of 1.5. Reduction solution is purified by

8 g/L activated carbon. Extraction rate of In is 97.5% above with In content in raffinate of

4 mg/L below after four-stage countercurrent extraction under the conditions including P204 concentration of 30%, acidity of

70 g/L, A/O=4U1, mixing time of

3 min, and temperature of

45 ℃. In concentration in stripping solution is

70 g/L above after four-stage countercurrent stripping under the conditions of

6 mol/L hydrochloric acid and A/O=1U12. Key words:indium-bearing calcium sulfate slag;

leaching;

reduction;

indium;

extraction;

stripping 铟是一种稀散金属,至今没有发现独立的铟矿床,主要赋存于闪锌矿及方铅矿中[1],广泛应用于高科技领域[2-3].随着铟用途的不断扩大以及资源的短缺,对铟进行综合回收具有重大意义.我国铟的生产原料主要以铅、锌冶炼废渣为主[4],含铟在100~1

000 g/t,回收铟的主流工艺流程为:铟渣浸出、净化、萃取、反萃取、锌(铝)片置换、海绵铟、粗铟、电解、精铟[5].为了更好地回收铟,通常先将含铟原料中的铟进一步富集得到更高品位的铟渣后再进行回收.火法富集以含铟锌渣为对象,主要有烟化炉挥发法、回转窑挥发法,铟富集于烟尘中;

湿法富集以含铟溶液为对象,主要方法有置换法和水解沉淀法[6-8]. 本文中的含铟硫酸钙渣产出过程为:高铁富铟锌弱酸浸出渣→热酸还原浸出→还原浸出液预中和→石灰中和水解沉铟.传统的沉铟中和剂一般为锌粉、氧化锌、焙砂.采用锌粉作中和剂,不仅成本高,而且有产生砷化氢有毒气体的危险;

采用氧化锌作中和剂,外购纯净氧化锌,成本较高,来自熔铸浮渣的氧化锌,含有大量氯离子;