富镁尾矿封存二氧化碳的实验地球化学研究  

CO2 Absorption and Precipitation Study Using Magnesium-based Tailings from Salt Lake Potassium Production

作　　者：王晗 朱辰 张猛龙 赵良[1] WANG Han;ZHU Chen;ZHANG Menglong;ZHAO Liang(Key Laboratory of Surficial Geochemistry Ministry Education,School of Earth Sciences and Engineering,Nanjing University,Nanjing 210023,China)

机构地区：[1]表生地球化学教育部重点实验室,南京大学地球科学与工程学院,南京210023

出　　处：《高校地质学报》2020年第3期303-312,共10页Geological Journal of China Universities

基　　金：国家自然科学基金项目(41772037,41273075)资助。

摘　　要：为了实现IPCC提出的控温1.5℃的目标,矿物封存因其具有长期稳定性和安全性的特点而成为研究热点,文章选取富镁尾矿作为封存原料进行研究。该尾矿为盐湖钾盐生产废弃物,由于无法利用,一直困扰当地产业。将其利用为封存二氧化碳的原料,可实现以废治废。文章通过实验研究不同反应温度(0、20、50、80℃)下二氧化碳吸收和碳酸盐沉淀两个核心过程,探讨二氧化碳在MgCl2-NH3-H2O体系中的反应路径和速率,发现二氧化碳在气—液界面的动力学反应速率常数是限制CO2传质的重要因素,对温度和反应速率常数进行建模发现两者关系为:kapp=1.4857×10^5 exp(-1974/T)。另外,通过对比不同温度下的二氧化碳吸收率和碳沉淀速率,提出最佳的实验温度条件,为富镁尾矿规模化封存二氧化碳提供参考。In order to achieve the goal of temperature control of 1.5℃proposed by IPCC,mineral sequestration has been widely studied due to its long-term stability and safety.This paper selects magnesium-based tailings as the raw material for further research.Magnesium-based tailings,as waste of potassium salt production in the salt lake,have been plaguing the local industry due to limited application.If used as a raw material for sequestration of carbon dioxide,it will have great storage potential.In this experiment,two core processes of CO2 absorption and carbonate precipitation were studied to investigate the reaction rate and path of CO2 in MgCl2-NH3-NH4Cl system under four different reaction temperatures(0,20,50,80℃).It was found that the kinetic reaction rate constant of CO2 at the gas-liquid interface is an important factor limiting CO2 mass transfer.Modeling temperature and reaction rate constant and their relationship was found to kapp=1.4857×10^5 exp(-1974/T).In addition,for the CO2 absorption rate and carbon precipitation rate of the magnesium carbonate precipitation process,the optimal experimental temperature conditions are proposed,indicating the potential for large-scale application.

关 键 词：二氧化碳 矿物封存 吸收率 温度 

分 类 号：P599[天文地球—地球化学]