Preparation and Properties of Agricultural Residuals-Iron Concentrate Pellets

Yayu Wang,Zhulin Liu,Zeping Gao,Xuegong Bi

doi:10.1155/2017/9407259

Abstract

In this paper, carbon-containing pellets were prepared by using crop-derived charcoal made from agricultural residuals and iron ore concentrates, and their pelletizing performance and properties were studied. Experimental results showed that the strengths of pellets were related to the particle size of concentrates and the content of moisture, bentonite, and crop-derived charcoal fines in the pelletizing mixture and the temperature of roasting and reduction. That the granularity of raw materials was fine and the bentonite content increased was beneficial to the improvement of pellet strengths. The suitable molar ratio of carbon to oxygen was 1.0 and the proper proportioning ratios of moisture and binder were 8.0% and 6.5%, respectively. The pellet strengths increased accordingly with increasing the reduction temperature, and when the temperature reached 1200°C, accompanied by the fast reduction of iron and the formation of crystal stock, the dropping strength of product pellets was 15 times and the compressive strength was 1650 N; this may be improved by grinding of the concentrate, leading to acceptable strength for the blast furnace.

Highlights

The sustainable development of the steel industry is severely restricted by natural resources, energy supply capacity, and the earth environmental bearing capacity [1]
Specific surface area was measured with BET technique and the results showed that specific surface area of charcoals (150∼350 m2/g) is 60∼350 times greater than that for PC (1.0∼2.6 m2/g)
After the disc pelletizer started running, the pelletizing mixture accounting for about one-third of the total weight of green balls was firstly added and water was dropped with a bottle onto the materials to form seed balls

Summary

Introduction

The sustainable development of the steel industry is severely restricted by natural resources, energy supply capacity, and the earth environmental bearing capacity [1]. Burning in the open air of a large number of surplus crop straw will produce a great deal of gases and aerosol components This will lead to a great waste of resources and destroy soil fertility, and bring about serious air pollution [4]. Mathieson et al [11] analyzed the potential for biomassderived charcoal to reduce net greenhouse gas emissions from the Australian steel industry and proposed many applications such as sintering solid fuel, cokemaking blend component, BF tuyere fuel injectant, BF nut coke replacement, BF carbon/ore composites of BOF prereduced feed, and steelmaking recarburiser. It is noted that there are few reports in the literature so far on the preparation and properties of crop-derived charcoal containing iron ore pellets. Feasibility of preparation of carbon composite iron ore pellets by using crop-derived charcoal was assessed and appropriate technological conditions were experimentally determined

Test Materials and Methods

Test Results and Analysis

Conclusions