| With the development of iron and steel industry, rich iron ore resources are depleted, while demand for iron ore resources are increasing, resulting in soaring of iron ore prices. Iron and steel companies are facing a huge financial pressure. There is large amount of marine sand vanadium-titanium magnetite of low price produced near the beach in Indonesia, and the resource is stable. Due to its low Fe and high Ti content, coarse grain size, compact structure, high hardness and melting point, etc., it can not be scale used in iron and steel production.This study is based on marine sand vanadium-titanium magnetite in Indonesia. According to the conditions of this kind of vanadium-titanium magnetite, appropriate treating processes are taken out to meet the needs of pellet production. Pelletizing experiments based on the raw materails conditions of some iron plant are approached to study the influence of adding ratio of vanadium-titanium magnetite in Indonesia to the process of pellet production and the metallurgical properties of pellets, providing a reference for the actual industrial applications.Main conclusions obtained in this paper are as follows:(1) The study on Indonesia sand ore dressing shows:the Eastern and Western iron ore belt is mainly magnetite type, lean ore essentially; magnetic iron in the marine sand is relative dominant, which can be recovered by low intensity magnetic separation method, obtaining concentrate iron ore with iron grade of60%after the election-heavy dressing eventually, and by considering better coordination with the actual implementation, as well as reducing investment and operation cost, direct ore dressing of original marine sand is advisable; after direct dressing, the iron and titanium content in iron concentrate is mainly distributed in the grain level between0.074mm and0.18mm, which is too crude to pelletizing, so fine grinding process is considered to be applicated for iron concentrate. (2) With a relatively low ratio of Indonesia vanadium-titanium magnetite (20%,30%), the radio change of Brazil PFCJ fine powder and northeastern fine powder affectes little on the compressive strength, falling strength, and pellet compressive strength index; with Indonesia vanadium-titanium magnetite ratio by0%-75%, the Brazil PFCJ powder and the northeastern fine powder ratio by1:1, Indonesia ore ratio shows no regular influence to pellet compressive strength, falling strength, pellet compressive strength, and each cold properties can all achieve the blast furnace application requirements; pelletizing with100%Indonesia vanadium-titanium magnetite, the pellet cracks after drying, leading to the pellet strength dropping dramatically. According to Indonesian vanadium-titanium magnetite’s own grade characteristics,100%Indonesia ore is not proposed to pelletizing. It should be used together with other high grade ores, increasing pellets grade and avoiding strength decline beceuse of cracks.(3) Along with the increasement of Indonesian vanadium-titanium magnetite proportion, reduction desintegration index (RDI+3.15>80%) enhances gradually, and mid-temperature reduction performance declines from74.3%to65.4%, declining9%; with addition of Indonesia vanadium-titanium magnetite, influence of reduction swelling of pellets is not obvious, the swelling rate of each experiment are all below16%, which belongs to the normal swelling range (<20%); under the same smelting condition, with addition of75%Indonesia ore, melting temperature interval of pellets is significantly narrowed, and higher temperature not only helps to improve the gas penetration potential of blast furnace burden and promote the intensified smelting, but also has great advantage in furnace maintenance low production costs. |
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