Research On Making Burnt Brick With Iron Tailings

With the scale of iron ore mining continuing to expand,there are more and more wastes of iron tailings.According to statistics,the total volume of iron tailings in the tailing reservoir of China has reached 5 billion tons.To deposit the large quantities of iron tailings will not only occupy huge area of land,but also result in a huge waste of resources.Dam of the tailings reservoir is prone to accident and fall,which would result in serious economic losses,environmental pollution and ecological disaster.Therefore,countries around the world attach great importance to the studies on technology of comprehensive utilization of iron tailings,with the view of changing waste into property,protecting the limited mineral resources and the human environment,reducing the harm extent of the iron tailings reservoir and ensuring the property of our country and people’s safety.In this paper,the feasibility of using iron tailings to make burnt brick,as a kind of wall materialist discussed based on the study of the characteristics of the iron tailings.And by a series of pilot studies and theoretical analysis,the best ratio of raw materials and the best roasting process parameters have been found,so as to produce the burnt brick that can reach the requirements of the wall material.This provides a new way for the comprehensive utilization of iron tailings.Main research work and results of this paper are as follows:(1)Fluorescence spectrometry X-ray diffraction analysis and differential thermal analysis are used to analyses the chemical composition and the mineral composition of iron tailings and clay,and it is found that iron tailings and clay have a similar chemical composition and mineral composition.Based on the chemical composition and the roasting mechanism of burnt brick,it is entirely possible that the iron tailings burnt brick that can reach the requirements of the wall material can be produced with appropriate composition ratio of the iron tailings adding some clay and melting material and strict conditions of the roasting process.(2)The roasting mechanism of burnt brick is introduced.Based on the principle of the orthogonal test design,the orthogonal test is designed to find the best roasting process parameters and the best ratio of raw materials.The test on the performance of the iron tailings burnt brick is taken,with compressive strength and roasting linear shrinkage rate as an index of performance.The results show that: The iron tailings burnt brick can get the best firing and performance indicators when the iron tailings clay ratio,the limestone content,the sub-heating rate,the sintering temperature and the heat-insulation time,are respectively 70:30,8%,40℃/h,80℃/h,45℃/h,1000 ℃and six hours.,under these conditions,the iron tailings burnt brick combines firm,has smooth surface without skin peeling off,and meets the performance requirements of wall materials.(3)Making use of the characteristics of iron tailings that contain a lot of Fe2O3,the feasibility of using iron tailings to make the electromagnetic shielding materials is discussed,The results show that: it is entirely possible that the Fe2O3 in iron tailings changes into Fe3O4 under the conditions of appropriate temperature and process,making iron tailings products with good function of electromagnetic shielding,so as to meet the special needs of electromagnetic shielding for some of the large-scale structure(such as air defense projects).The results of this paper can effectively solve the problems of resources recycle and utilization,environmental pollution and potential safety of iron tailings waste,and the popularization and application of the results are of great value and can achieve remarkable social,ecological and economic benefits.