超声波增强炼钢渣中钙的浸出用于CO_(2)矿物封存

Enhancement of leaching of Ca from steelmaking slag by ultrasonic for CO_(2) mineral sequestration

炼钢渣是一种含有大量硅酸钙的碱性废物,可用于钢铁企业捕获CO_(2)并合成高附加值的CaCO_(3)。在此研究了在乙酸溶液中超声对炼钢渣中Ca的浸出率和选择性提取率的影响。试验结果表明,超声功率、液固比和乙酸溶液的初始浓度与Ca的浸出率呈正相关,但炼钢渣的粒度和温度与Ca的浸出率呈负相关。温度和乙酸溶液的初始浓度与Ca的选择性提取率呈负相关。此外,超声功率和固液比对Ca的选择性提取率影响不大,但增加超声功率和固液比会增加非钙杂质元素的浸出率。在0.5 mol/L乙酸水溶液中提取0.96μm以下炼钢渣中的钙,反应40 min后Ca的选择性提取率高达96.7%。在浸出过程中,超声可以有效打破和去除炼钢渣颗粒表面残留的二氧化硅形成的多孔钝化层,提高Ca的浸出率。

Steelmaking slags containing large amounts of Ca silicate is a potentially alkaline waste that can be used to capture CO_(2)to synthesize high-quality CaCO_(3).Here,effect of ultrasonic on leaching efficiency and selective leaching rate of Ca in steelmaking slags was studied in acetic acid solution.Experimental results shown that ultrasound could help to strengthen leaching of Ca in acetic acid solution.Ultrasonic power,liquid-solid ratio,and initial acetic acid solution concentration were positively correlated with Ca extraction,but particle size of steelmaking slags and temperature were negatively correlated with Ca extraction.Meanwhile,temperature and initial concentration of acetic acid solation had a negative correlation to selective extraction yield of Ca,which were beneficial for the diffusion of impurity elements.Also,ultrasonic power and solid to liquid ratio were insignificant effect to selective extraction yield of Ca,but increase of ultrasonic power and solid to liquid ratio were also helpful to the diffusion of impurity elements.It was worth noting that decreasing grain size of steelmaking slags would raise selective leaching efficiency of Ca and the maximum selective leaching rate upped to 96.7%.During leaching process,ultrasonic could effectively break and remove the porous passivation layer formed by residual silica on surface of steelmaking slags particles,and improved leaching rate of Ca.