水热臭葱石固砷过程Na^(+)和K^(+)的影响  

Effect of Na^(+)and K^(+)on Hydrothermal Arsenic Solidization by Scorodite

作　　者：邓戈 罗劲松 李存兄[1] 张鹏 李玉东 张德超 向成喜 袁杰 徐刚芳 DENG Ge;LUO Jin-song;LI Cun-xiong;ZHANG Peng;LI Yu-dong;ZHANG De-chao;XIANG Chen-xi;YUAN Jie;XU Gang-fang(Faculty of Metallurgical and Energy Engineering,Kunming University of Science and Technology,Kunming 650093,China;Southwest Copper Branch of Yunnan Copper Co.,Ltd.,Kunming 650102,China)

机构地区：[1]昆明理工大学冶金与能源工程学院,昆明650093 [2]云南铜业股份有限公司西南铜业分公司,昆明650102

出　　处：《有色金属（冶炼部分）》2023年第3期1-7,共7页Nonferrous Metals（Extractive Metallurgy)

基　　金：国家自然科学基金资助项目(52064034);云南省重点研发计划资助项目(202202AB080005);国家重点研发计划项目(2021YFC2902801)。

摘　　要：水热臭葱石沉砷体系中Na^(+)、K^(+)碱金属离子对沉砷渣物相组成影响显著,Fe(Ⅲ)与As(Ⅴ)共沉淀生成臭葱石(FeAsO_(4)·2H_(2)O)、次水合砷酸铁(FeAsO_(4)·0.75H_(2)O)砷铁共沉淀物,同时Fe(Ⅲ)还以黄钠铁矾(NaFe_(3)(SO_(4))_(2)(OH)_(6))、黄钾铁矾(KFe_(3)(SO_(4))_(2)(OH)_(6))、碱式硫酸铁(Fe(OH)SO_(4))形态竞争析出,从而影响沉砷渣的稳定性。在Na_(2)SO_(4)-(K_(2)SO_(4))-FeSO_(4)-H_(3)AsO_(4)-H_(2)O体系中研究了Na^(+)、K^(+)的存在及其浓度变化对砷铁沉淀率、沉砷渣物相组成及转变规律和沉砷渣稳定性的影响。结果表明:当体系Na^(+)、K^(+)共存时,砷、铁沉淀率分别为98.6%、94.5%,获得以臭葱石、黄钾铁矾及黄钠铁矾为主并伴有少量碱式硫酸铁的沉砷渣,沉砷渣含As 21.2%、Fe 27.1%、Na 0.2%,K 2.0%、S 4.84%。亚稳态铁矾物相的生成导致沉砷渣浸出毒性试验中As浓度超过标准限值(5 mg/L),通过控制初始铁砷摩尔比,适当升高反应温度、延长反应时间可抑制铁矾物相的形成或促进其转化为臭葱石物相。The effect of alkali metal ions of Na^(+)and K^(+)on phase composition of As-bearing precipitate in hydrothermal arsenic solidization system is remarkable.In addition to co-precipitation with As(Ⅴ)to form scorodite(FeAsO_(4)·2H_(2)O)and sub-hydrous ferric arsenate(FeAsO_(4)·0.75H_(2)O),Fe(Ⅲ)will also competitively precipitate as Na-jarosite(NaFe_(3)(SO_(4))_(2)(OH)_(6)),K-jarosite(KFe_(3)(SO_(4))_(2)(OH)_(6))or basic ferric sulfate Fe(OH)SO_(4),thereby affect the stability of As-bearing precipitate.The effect of Na^(+)and K^(+)on precipitation rate of arsenic and iron,composition of precipitate,transformation of mineral phase,and the stability of precipitated were studied in the system of Na_(2)SO_(4)-(K_(2)SO_(4))-FeSO_(4)-H_(3)AsO_(4)-H_(2)O.The results show that with the co-existing of Na^(+)and K^(+),the precipitation rate of As and Fe is 98.6%and 94.5%respectively,and the As-bearing precipitate mainly composed of scorodite,Na-jarosite,K-jarosite,and is concomitant with a small amount of basic ferric sulfate.The precipitate contains As 21.2%,Fe 27.1%,Na 0.2%,K 2.0%and S 4.84%.The formation of metastable phase of jarosite causes As concentration exceeds the standard limit(5 mg/L)in the leaching toxicity test of As-bearing precipitate residue.Increasing reaction temperature and prolonging reaction time can inhibit the formation of jarosite phase or promote its transformation into scorodite.

关 键 词：水热体系 臭葱石 铁矾 沉砷率 

分 类 号：TF803[冶金工程—有色金属冶金] X52[环境科学与工程—环境工程]