High-yield synthesis of carbon nanotubes in-situ on iron ore tailing

Abstract

This study reports the high-yield, “in-situ” growth of multi-walled carbon nanotubes on iron ore tailing. The final product is a pioneering approach on the use of nanostructured tailing to produce mortar with improved mechanical properties in a simple, effective methodology. Four different high-yield catalysts were developed to identify the most efficient parameters for the synthesis of carbon nanotubes (CNT) via Chemical Vapor Deposition on iron ore tailing (IOT). The process yields 1800% in carbon mass, an unprecedented result. Nanostructured IOT was used to produce mortar with different CNT quantities, including concentrations highly above the limits found in the literature, and resulted in increases of in flexural strength (up to 30%). Water loss after thermal treatment, consistency index and water absorption as a function of the CNT concentration in the mortar mass were also investigated. The proposed method delineates a viable way of incorporating CNT-reinforced macromaterials into cementitious matrices without functionalization, additives, or surfactants, which represents an advance for the nanocomposites industry. It also contributes to social and environmental development by aggregating value to iron ore tailing that would be otherwise stored in huge, and sometimes dangerous, disposal dams.