The Emission Characteristics Of Fine Particles Of Sintering Flue Gas And Its Relationship With The Interface Chemistry Of Polymer Agglomerating Agent Solutions

Fine particulate matter（PM）is the main pollutant that induces the haze in China and poses a serious threat to people’s life and health.The sintering process is an indispensable part of modern steel production processes,but it is also the largest source of PM₁₀and PM_2.5emissions in the steel industry,accounting for about 40%of its total emissions.Therefore,the study of the emission characteristics of fine particles in the sintering process of iron ore,and its interface chemical relationship with polymer agglomeration agents were carried out,which are important for the reduction of particulate matter in the sintering process.In this paper,the micro-particles produced during the experimental process of sintering pots were detected by the low voltage impinger（ELPI+）produced by the Dekati company in Finland.The morphology of the collected particles were analyzed by SEM-EDS,and the interfacial chemical relationship between the particles and the polymer chemical reagents was studied.The results show that the concentrated release of PM₁₀in the sintering process occurs in the temperature rising stage,and the mass concentration and nμmber concentration of PM₁₀reach the highest value in the temperature rising stage.In terms of mass concentration,PM_2.5does not dominate in PM₁₀,but in nμmber concentration,PM_1.0dominates PM_1.0.The elements of Fe,O,Na,Mg,S,K,Cl,Ca,and other elements are commonly present in different fine-grained fine particles.The Ca,Mg,and O elements exist in the form of CaO and MgO.K and Na are mainly combined with Cl and exist in the form of KCl and NaCl in the particles.In terms of topography,PM_2.5has a regular spherical shape and a square shape,in which the square-shaped particles have a large particle size.It is preliminarily believed that in PM_2.5,a part of particles below 1μm comes from the way that the low-melting point substance in the ore powder and fuel is condensed by gasification,and the other part comes from the ultrafine coke powder that is not completely burned in the raw material.Part of the particles above 1μm may come from the mineral fines and flux that burst due to the increase of internal stress,and the other part comes from the ultrafine sintering raw materials.Through the study of the contact angle,the Zeta potential and the surface tension of the particulate matter（including fine particles）of sintered flue gas and the macromolecular agglomeration agent,it was found that the three polymeric agglomeration agents of CMC,SDBS and PAM can improve the interface chemical relationship with the particles.At the same concentration,the contact angle between the PAM solution and the particles was the smallest,and the SDBS solution had the best aggregation effect on the particles.The surface tension of the CMC solution was the lowest.The polymer agglomeration solution can strengthen the agglomeration of the sintered particles,so that the fine particles adhere around the coarse particles,forming large particles that are easy to trap,thereby facilitating the reduction of the fine particles.