The balance calculation of zinc and lead of No.1 BF of Baotou Iron and Steel Group Co. was performed in this research. The particle sizes of BF dusts were measured by LS230 laser particle size analyzer. The micrology of sinter and dusts were investigated with scanning electron microscopy (SEM, Hitachi S-3000) coupled with an energy-dispersive X-ray analysis (EDX). The results show that the general burdens of zinc and lead in No. 1 mainly came from sinter and pellet. The burdens of zinc and lead in No.1 BF were 645.45g/t and 370.33 g/t respectively, which were too much to need take some measures. Among the gas ash, the particle size of baghouse dust was minimal, but the contents of lead and zinc were highest. So the BF baghouse dust isn’t appropriate to recover as the sintering materials. The speciation of lead is PbO, PbCl3 and metallic Pb, but zinc never presents as metal in BF dusts.

The effects of compound silicate gangue on mineral composition and microstructure of sinter produced by Baiyunebo iron ore concentrates was studied by using mini-sintering test device and optical microscope. The result showed that compound silicate gangue has lower melting point, wider melting temperature range, longer melting time and melts easily to form glassiness during the sintering process. It can promote the solution of CaO and CaF2 in glassy phase, which affects viscosity and fluidity of glassy phase as well as the homogeneity of sinter microstructure. The compound silicate gangue intensely inhibits the generation of complex calcium ferrite and cuspidine as well. The major mineral compositions of sinter are hematite and glassy phase. The sinter exhibits multi-cavities and grainy structure when SiO2 exists entirely in the form of compound silicate gangue.

In this paper, the crystallization behavior including crystallization temperature, nucleation temperature, microstructure of glass-ceramics and crystal phase composition during preparation of glass-ceramics by melting method from blast furnace(BF) slag of Baotou iron and steel company, quartz sand and other materials was investigated using differential thermal analysis, X-ray diffraction and scanning electron microscopy. The results show that the crystallization peak temperatures of the parent glasses are 962~966°C when the ratio of blast furnace slag changes from 20% to 50%, and uniform, compact grains in the prepared glass-ceramics are obtained, whose diameters are about 0.2-0.5μm. In addition, the major crystalline phases are identified as diopside(Ca(Mg,Al)(Si,Al)2O6）and diopside containing aluminum(Ca(Mg0.5Al0.5)(Al0.5Si1.5O6), and the mechanical properties of glass-ceramics are good, among which the flexural strength is more than 110Mpa. The results have theoretical guidance meaning and practical reference value for realizing industrial production of preparation of glass-ceramics from BF slag of Baotou iron and steel company.

A typical kind of silicate gangue — sodium pyroxenite (mainly containing NaFeSi2O6) in Baiyunebo iron ore is selected as the research object in this paper. The endothermic peak and the change of quality is definited by means of thermal analysis (DSC and TG) in the rising process. And then the samples are sintered at the peak temperatures. The main ingredients of sodium pyroxenite and the resultants are definited by means of X-ray diffraction analysis (XRD). The experiment ascertains the change law of physical and chemical properties of sodium pyroxenite such as thermal decomposition, softening, melting temperatures and the corresponding resultants, which provides basic data for exploring the formation mechanism of complex calcium ferrite (SFCA) in baogang special sintered ore.

The changes of physical and chemical properties of sodium pyroxenite gangue such as decomposition and phase transformation were researched by means of differential thermal analysis and X-ray diffraction. The results show that the natural sodium pyroxenite gangue contains the main mineral of aegirite(NaFe+3Si2O6), and it contains a number of BaSO4 and Na3Ca2(SO4)3F, etc. The water of crystallization decomposes at 554.7°C. The Na3Ca2(SO4)3F decomposes into the composite sulfate and CaF2 over a wide range of temperatures. The main mineral of aegirite(NaFe+3Si2O6) reacts with CaF2 into NaF gas at 993.4°C. The sodium pyroxenite gangue is melts and releases a small amount of SiF4 gas in the range of 1193.5-1300.7°C.