基于铁矾渣剂、熔剂的成分及物相组成,选择PbO-CaO-SiO2-FeO-ZnO为熔炼过程基本渣系,采用FactSage热力学软件绘制该渣系相图,结合相关炉渣性能测定试验,探索随FeO/SiO2比和CaO/SiO2比等的改变对炉渣物化性能的影响.结果表明,熔炼过程不添加其他熔剂条件下,炉渣中FeO/SiO2比在0.92～1.53变化时,随着FeO/SiO2比增大,炉渣熔化温度增高,当FeO/SiO2比为0.92时炉渣熔点最低,为1338℃.CaO/SiO2比在0.3～0.8变化时,随着CaO/SiO2比增大,炉渣熔化温度呈现降低趋势,当CaO/SiO2比为0.78,炉渣熔点最低,为1385℃.对低熔点渣型进行黏度测定,可知在1500℃黏度均在0.5 Pa·s以下,满足冶炼对流动性的要求.提出了添加CaO同时减少SiO2至CaO/SiO2比为0.78的优化调渣方案.调渣后渣中主要物相以磁铁矿和硅酸盐为主,有利于后续提铁.

铝电解生产过程中产生的废旧阴极(SPL)含有浸出毒物氟化物(以F-计)和氰化物(以CN-计),对环境造成巨大威胁.采用高温真空焙烧法去除废旧阴极中的氟化物和氰化物.在FactSage热力学计算的基础上,研究了温度、真空度和坩埚材质对浸出毒物去除效果的影响.结果表明,在真空度10 Pa、温度1100℃下,使用石墨坩埚焙烧废旧阴极,浸出毒物的去除效果最佳.结合TG-DSC分析,发现高温真空环境中,氟化物发生分解并挥发,氰化物也能分解成无毒物质,处理后的废旧阴极可由危废转变为一般固废,实现电解质和碳质材料的有效分离,便于综合利用.

Silico-manganese slag is a main solid waste produced from production of silicon-manganese alloy, which affects the environment. It is thus necessary to explore the corresponding disposal methods since the exsiting processing technology restricts the absorbing capacity. A microcrystalline cast stone was fabricated by the Petrurgic firing method with silico-manganese slag as a raw material. The bulk density, microhardness, flexural and compressive strength of the samples were determined. The influences of crystallization temperature and time on the phase structure and properties of the finished product were invesigated. The results show that a hot molten slag is cooled to 950 ℃ for 60 min and then annealed at 760 ℃ , obtaing a microcrystalline cast stone with the superior properties. The microcrystalline cast stone has a compact structure, and the precipitated crystal phases are mainly clinopyroxene, diopside and aluminum diopside, as well as anorthite and wollastonite. The bulk density of the cast stone can reach 3.11×103 kg·m–3, the microhardness is 8.77×103 MPa, and the flexural strength and the compressive strength are 86 MPa and 222.9 MPa, respectively.