Zhengqi Guo

Preparation of oxidised pellets using pyrite cinders as raw material

Abstract Pyrite cinders are a solid waste generated by the sulphuric acid industry and are considered environmentally hazardous. In order to try and recycle this material as a source of Fe units, the effects of different ratios of pyrite cinders to magnetite concentrate on the qualities of green and roasted pellets were evaluated. The results show that sulphur mainly exists as elementary sulphur in pyrite cinders and was nearly removed at the preheating stage. The higher the pyrite cinder content, the greater the porosity of the roasted pellets, leading to low compressive strength of the roasted pellets. Roasted pellets with acceptable quality for industrial use were obtained under the conditions of 40% pyrite cinders and 60% magnetite concentrate, preheating at 1000°C for 15 min and roasting at 1300°C for 15 min.

A study of pre-briquetting granulation sintering of the mixtures with high ratio of Brazilian specularite concentrate

In the paper, the pre-treatment of fine Brazilian specularite concentrates with high iron grade and low impurities through pre-briquetting was proposed to improve the granulation and sintering performance of blends comprising some 30% specularite concentrates. The results show that the excellent sintering indexes are attained as follows in pot tests: productivity of 1.64 t m−2 h−1, tumble index of 59.87% and solid fuel consumption of 71.64 kg t−1 under the optimal conditions. Compared with traditional sintering process, productivity and tumble index were increased by 13.88 and 3.5%, respectively, and solid fuel consumption decreased by 4.82 kg t−1. The RI and RDI−3.15 reach 83.95 and 35.02%, respectively, which are superior for blast furnace. The mechanism of the pre-treatment of the specularite concentrates was demonstrated that better permeability was achieved by coarsening granule, more calcium ferrite was formed by basicity segregation and separation addition of coke.

Grate-kiln pelletization of Indian hematite fines and its industrial practice

Indian hematite fines normally have a high iron grade and minor impurities; they are usually used as sinter fines for feeding into a blast furnace. In this work, the grindability properties of two kinds of Indian hematite fines and the roasting behaviors and induration characteristics of pellets made from these fines were revealed through experiments involving dry ball milling and small-scale and pilot-scale tests. In addition, the microstructures of the particles of ground India hematite fines and fired pellets were investigated using optical microscopy. On the basis of the results, a grate-kiln production line with an annual output of 1.2 Mt of oxidized pellets was established in India. This pellet plant operates stably and reliably, further confirming that preparing high-quality pellets with Indian hematite fines pretreated by dry ball milling is an industrially feasible process.

The correlation between high temperature properties and sintering performance of Australian iron ore fines

ABSTRACTThe characteristics of iron ore fines were considered to have tremendous effects on their subsequent sintering performances, but it is difficult to judge their sintering performances only b...

Improving the sintering performance of blends containing Canadian specularite concentrate by modifying the binding medium

Canadian specularite concentrate (CSC) possesses high total iron grade and low impurity content. However, due to the poor granulating performance and weak reactivity of CSC at high temperature, the proportion of CSC used in sintering blends is restricted. In this research, the effects of fine limonite, slake lime, and bentonite particles on the granulation performance of blends containing a high ratio of CSC were studied through granulation test. Based on the test results, the effects of modification of the binding medium on the sintering performance of blends containing a high ratio of CSC were revealed by the sintering pot test. Both the granulation property and sintering performance of blends with a high proportion of CSC were improved by modifying the binding medium.

Improving Separation of Cu–Fe from Copper Slag by Modification of the Molten Slag

Iron mainly exists as the magnetite and fayalite, while copper is primarily dispersed in the form of fine matte particles in the copper slag, which is difficult to recover by conventional separation techniques. In this paper, the feasibility of an integrated technological route to improve beneficiation of copper and iron components from copper slag through the modification of molten slag was investigated, and the results shows that: the copper grade of rougher copper concentrate was increased from 6.43 to 11.04%, iron recovery from magnetic separation was increased significantly from 32.40 to 63.36%, and other evaluation indexes were changed slightly, in comparison with unmodified copper slag. Meanwhile, the grains of the target minerals in the modified slag grew considerably to a mean size >50 μm after slow cooling. Ultimately, the beneficiation efficiency of copper and iron was improved because of the ease with which the target minerals were liberated.