Basic Research On Preparation Of Ecological Cementitious Materials With Lead-Zinc Slag

Haiyan Lake Chemical Zone has abundant lead-zinc ore reserves.The lead-zinc smelting industry discharges a large amount of lead-zinc smelting waste while meeting the major needs of national and local economic development.The lead-zinc slag formed by the water quenching cooling process contains a certain amount of silicon-calcium-aluminum element glass body,which has potential hydration activity.In response to this phenomenon,this paper systematically studied the chemical composition,mineral composition,microscopic morphology,grinding index,toxicity leaching and other characteristics of lead-zinc slag,and studied the self-gelling activity of lead-zinc slag.At the same time,a small amount of brucite,calcium-based solid waste and cement are used as activators to prepare lead-zinc slag-based ecological cementing materials.Through four-factor four-level orthogonal test,the influence of each factor on its mechanical properties is studied.The hydration products of lead-zinc slag ecological cementitious materials are micro-analyzed,and the hydration process and hydration mechanism of lead-zinc slag-based cementitious materials are studied.Research on basic physical and chemical properties shows that the toxicity of lead-zinc slag meets the concentration specified in the identification standards for hazardous waste and general industrial waste;lead-zinc slag itself has certain activity,but the activity is not high.Orthogonal test results show that the content of chlorite is 3%,the total solid waste content is 70%,the calcium-based solid waste is 16%,the water-cement ratio is 0.4,and the 28 d compressive strength of the cementitious material cured at room temperature reaches 9.7 MPa.Steam curing can further improve its compressive strength to a certain extent.Microstructure analysis shows that the cementitious material presents a disordered honeycomb network structure after 28 days of hydration.During the hydration process,the hardened body structure is dense,and the internal micropores are mostly harmless pores less than 50 nm,and more harmful than 100 nm.Less;the lead-zinc slag ecological cementing material has undergone polymerization reaction,the Si-O bond gradually polymerizes into the Si-O-Si bond,and the degree of polymerization of silicon-oxygen tetrahedron in CSH increases.