Comprehensive Utilization Of Resources Containing Titanium Slag

Based on the comprehensive summary review of Pangang Ti-bearing blast furnace slag, an effective resource utilization method is presented to prepare photocatalytic absorbent from Ti-bearing blast furnace slag so that added values can be created. The general technical process is:Perform hydrochloric-acid leaching treatment to Ti-bearing blast furnace slag so that the titanium element will be enriched in acid leached slag. Then, an analysis of photocatalytic and absorption performance will be carried out on the slag to obtain photocatalytic absorbent. Detailed research contents and results of this thesis are as follows:Firstly, use hydrochloric acid leaching method to prepare acid leached slag with high titanium. The impact of reaction condition on titanium proportion in the slag will be investigated then to optimize the technical process, the results of which are:slag with a granularity of raw materials from120to180μm, a heating temperature of95℃; an acid slag ratio of1.5:1(mL:g); a hydrochloric acid concentration of8mol·L-1; a reaction time of4h; a stirring speed of1400r·min-1. acid leached slag with more than45%of TiO2can be obtained.The acid leaching reaction kinetics is aligned with the unreacted shrinking core model, and the leaching process belongs to internal diffusion control.In addition, according to X ray diffraction (XRD), scanning electron microscopy (SEM) and specific surface area (BET) analysis, the leaching rate of Ti-bearing blast furnace slag under different phase compositions descended from spinel to diopside to perovskite. Leached slag has a large specific surface area to achieve excellent absorption performance.Secondly, use acid leached slag as photocatalytic material to degrade methyl orange solution. This thesis analyzes impacts of different factors on catalytic degradation of methyl orange, such as heating treatment temperature, catalyst dosage, illumination time, initial solution concentration, solution pH and addition of strong oxidizer H2O2. The results show that a heating treatment temperature of400℃and a catalytic dosage of10mg will optimize degradation performance; the longer illumination time is, the higher degradation efficiency is; a lower initial solution concentration and a lower pH will yield a better photocatalytic effect; Adding H2O2reaches an outstanding effect, a thimbleful amount can improve the photocatalytic efficiency to above95%. The reaction of photocatalytic reduction follows L-H dynamic rules. Finally, this thesis studies the absorption rules of formaldehyde for various types of acid leached slag prepared from different processes. Based on single factor analysis, the optimal preparation process is:a granularity from120to180μm, a heating temperature of95℃; an acid slag ratio of1.5:1(mL:g); a hydrochloric acid concentration of8mol·L-1; a reaction time of6h; a stirring speed of1400r·min-1and a calcining temperature of600℃. The Langmuir equation can be used to express the optimal isotherm model of formaldehyde absorption for acid leached slag.the expression of which is:1/qe=3.061/Ce+0.45showing a monolayer formaldehyde absorption. The quasi secondary dynamics equation can be used to express the optimal dynamic model, the expression of which is:t/q=9.605/+0.154, showing that the absorption process is mainly affected by chemical absorption control.This thesis shows that acid leached slag prepared from hydrochloric-acid leaching of Ti-bearing blast furnace slag has an outstanding photocatalytic and absorbing performance, and can be used to photocatalysis and absorb formaldehyde and methyl orange. The research outcomes of this thesis can provide experimental foundation as well as theoretical basis for resource utilization of Ti-bearing blast furnace slag.