Studies On Preparation Of Nano-CaCO₃ From Carbide Slag And The Adsorption Of Heavy Metals

Carbide slag is a waste with high humidity and high calcium,and most enterprises usually recycle it as low value-added cement raw material or lime raw material,even directly air storage,air drying or landfill.These approaches not only occupy a large amount of land and increase the cost of disposal of enterprises,but also cause pollution of soil,water and air in the vicinity,which become important factors limiting the industry development and hindering the protection of ecological environment.Therefore,how to realize high efficiency treatment and resource utilization of carbide slag is a difficult problem which demand prompt solution.In recent years,the pollution of heavy metals to the environment is becoming more and more serious in our country.Water pollution is one of the most common and most serious pollution.We should not only prevent the pollution of heavy metals to the environment,but also take effective methods to deal with it in time.In this work,a CO₂ storage material（CO₂SM）was prepared from 1,3-butanediol（BTD）+ethylenediamine（EDA）system by absorbing carbon dioxide（CO₂）.The basic thermodynamic properties of BTD+EDA system were systematically studied,and the important density and viscosity data were obtained,which made up for the blank of the data at home and abroad.Calcium hydroxide（Ca（OH）₂）,giving calcium resource,was used to simulate carbide slag,and CO₂SM gives CO₃^2-.Controlled morphology and crystal shape of nano-CaCO₃ particles were prepared by ultrasonic,and the reaction conditions were explored.The characterization of nano-CaCO₃ particles was completed by several modern instruments including field emission scanning electron microscope（FESEM）,fourier transform infrared spectrometer（FTIR）,X ray diffractometer（XRD）and high resolution transmission electron microscopes（HR-TEM）and thermal gravimetric analyzer（TGA）.The results showed that the nano-CaCO₃ particles have the crystalline form of calcite,aragonite,and vaterite.The suitable reaction conditions,such as 45 min reaction time,25?C reaction temperature,300 W ultrasonic power,16 g/L CO₂SM,0.4125 g/L Ca（OH）₂ solution,were used to study the preparation of nano-CaCO₃ particles based on carbide slag.And the nano-CaCO₃ particles were used to complete the adsorption of heavy metal ions such as Pb²⁺and Cd²⁺,at the same time,the adsorption of Cu²⁺and Co²⁺was investigated as a reference,and a good removal efficiency was obtained.This process has achieved the efficient adsorption of heavy metal ions,and provided a new reference for the disposal of industrial heavy metal wastes and the recycling of carbide slag.