| Chromite is an important raw material for the production of stainless steel.As the world’s largest stainless-steel producer,China’s chrome ore resources are insufficient and unevenly distributed,and will be highly dependent on imports in the future.With the expansion of the stainless-steel industry,China has a huge demand for chromium resources.Chromium resources in the wastes generated by the stainless-steel industry have value in utilization,and the toxic and harmful substances produced during the stacking of chromium-containing wastes will have a significant impact on the environment,animals,plants and human health.The effective recovery of chromium resources from stainless steel waste not only protects the environment,but also reduces the waste of resources.Because of its good detoxification effect and high added value,glass-ceramic is a current research hotspot.Compared with the traditional two-step method,the one-step method,which completes crystallization and nucleation in one step,saves process steps and reduces energy consumption to a certain extent.In order to effectively utilize the chromium-containing stainless steel slag and optimize the production process,according to the composition of the chromium-containing stainless steel slag and considering the chromium-fixing properties of the material,the composition of anorthite:diopside=1:1 was designed and the following studies were carried out..The thermodynamic software FactSage 7.2 was used to calculate the isothermal projected equilibrium surface and the content of the generated phase,and the reliability of the component and the possible reactions during the melting process were obtained.In order to study the influence of chromium content and other additives on the composition,the content of the generated phase in the system after adding these substances was also calculated.The calculation results show that this component can generate diopside and anorthite phases at the same time,and the system is more inclined to generate anorthite phase.The chromium-containing phase is preferentially enriched in the spinel phase,and the excess Cr exists in the system in the form of Cr2O3.On the basis of the calculation results of thermodynamic software,glass-ceramics were prepared by using pure substances to simulate the composition of chromium-containing stainless steel slag to study the optimal heat treatment system of the material.By changing the chromium content in the composition,the results of X-ray diffraction test and scanning electron microscope were observed,and the effect of chromium content on crystallization was also studied in this part of the experiment.The experimental study shows that the optimal heat treatment system for parent glass is1090℃for 4h.The main crystallization peak intensity of the material decreased with the increase of chromium content,and the microstructure also showed that the grain size of the material gradually became smaller with the increase of chromium content.In the hardness performance test,the optimum hardness condition is that the heat treatment temperature is 1090℃,and the hardness is 1447.1 when the temperature is kept for 4 hours.On the basis of the above experiments,using the actual stainless-steel slag as the main raw material,the effects of flux,chromium content and crystal nucleating agent on the crystallization performance,chromium fixing performance and physical properties of the material during the one-step preparation of glass-ceramic from actual electric furnace slag were studied.performance impact.The chromium leaching experiment was carried out on the prepared materials,and the results showed that no chromium-containing phase was detected in the prepared steel slag,and the process achieved the purpose of detoxifying the stainless steel slag. |
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