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.
作者
邓戈
罗劲松
李存兄
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)
出处
《有色金属（冶炼部分）》
CAS
北大核心
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)。
关键词
水热体系
臭葱石
铁矾
沉砷率
hydrothermal system
scorodite
jarosite
arsenic precipitation rate
