3rd International Symposium on High-Temperature Metallurgical Processing Edited by: Tao Jiang, Jiann-Yang Hwang, Patrick Mast, Onuralp Yucel, Rafael Padilla, and Guifeng Zhou
TMS (The Minerals, Metals & Materials Society), 2012 A STUDY OF CARBON-BURDENED AND COLD-BONDED PELLETIZING-ELECTROSMELTING PROCESS DISPOSING LOW-GRADE MANGANESE ORE
Zhao Qiang Ning Shun-ming Chen Wen Tang Sanchuan Li Zhao-jia Wan Hong-qiang
Changsha Rearch Institute of Mining and Metallurgy, Changsha 410012,China
ABSTRACT The carbon-burdened and cold-bonded pelletizing-electrosmelting process is ud to dispo low-grade mangane, and the qualified rich-mangane slag is obtained. On the condition that reduction roasting temperature was 1000℃, reduction time was 45min, particle-size was -1mm, reductant dosage was 1.6%, basicity was 0.3, smelting temperature was 1410℃, smelting time was 60min, it had a good effect on the melting between slag and metallographic pha, the mangane content was 32.58%, mangane recovery was 92.16% in the slag; while the iron content was 94.40%, iron recovery was 95.32% in the metallographic pha. It was proved by the demonstration tests.
KEY WORDS carbon-burdened; cold-bonded pellets; low-grade mangane; electrosmelting
Introduction
Mangane is an important raw material for steelmaking, which is extensively utilized in modern industry, the consumption of mangane for iron and steel industry accounts for 90% to 95%. After mining over 30 years, the high-grade mangane resources drop markedly, especially with the hypergrowth of steel industry, the domestic mangane is far from the requirement , as a result, we have to buy significant quantities of mangane overas. Besides, the property of imported mangane is more and more complex, and the high-grade and lump mangane decrea year by year, while the fines and high-crystal water mangane are on the increa. Therefore, how to make effective u of domestic low-grade mangane and intensify the mangane’s smelting is an effective approach to reduce the cost of mangane ries ferroalloy and improves market competitiveness[1-4]. It has important practical meaning.
After years of rearch on low-grade mangane, a lot of developments have been achieved in the field of ferromangane smelting, rich-mangane slag, Si-Mn alloy, electrolytic mangane dioxide and manganous-manganic oxide. According to the component content and mineral pro
perties of mangane ores, the right smelting process must be chood. Carbon-burdened and cold-bonded pellets–electrosmelting process, namely rich-mangane slag process, is an effective way to dispo low-grade mangane, which is only for low-grade mangane.The product rich-mangane slag is mainly ud for ferromangane smelting. Rich-mangane slag process is an enriching mangane ore method which accords with Chine actual conditions, becau China has very little rich-mangane, and high iron-high phosphorus-refractory mangane accounts for 40% of mangane ore rerves[5]. For the reasons, we u carbon-burdened and cold-bonded
超人的英文pellets–electrosmelting process to deal with low-grade mangane from Hunan Province, and we can obtain qualified rich-mangane slag.
1. Raw Material Characteristics and Experimentation Methods佛山室内设计培训
1.1 Characteristics of Raw Material
1.1.1 Low-grade mangane
The chemical composition of the Hunan’s low-grade mangane is shown in Table1. It indicates that this mangane is a low-grade mangane , according to the mangane grade. The distribu
cbd什么意思tion size of the low-grade mangane is shown in Table2, it can be en that the size is quite coar, so the blend have to be crushed before briquetting experiments.
Table3 Mineral Pha Analysis of Iron and Mangane in The Low-grade Mangane Ore /%
according to the results, we can e that the main existence form of iron is limonite and the proportion is 97.5%; while the main existence form of mangane is mangane oxide and the proportion is 92.3%.
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1.1.2 Reductant
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Coke breeze is ud as reductant for the experiment. It is broken to -2mm, the industrial analysis of coke breeze is shown in Table4. It is obrved that this coke breeze is a good reductant, becau its Fcad is high and its Vdaf is low.
1.2 Experimentation Method
The 300g low-grade mangane is mixed with proportional coke breeze and silica, and then we crush them to different size fraction; the equipment ud for granulation is 10B Type Hydraulic Universal Tester, and the pressure is fixed at 350kg/cm2，after granulation, the compressive strength of green pellets is 10kg, while the standard is Φ25 mm×20 mm ; then we put the
agglomerate into the Type FN202-1 Electrically Heated Drying Cabinet for drying and concreting (200℃)for two hours, the compressive strength of dried agglomerate is 50kg; the next, we place the dried agglomerate into SX2-12-16 Box Type Resistance Furnace, the reduction roasting conditions are as follows: the temperature increa from room temperature to 1000℃, stay for 45min,being reduced. After reduction roasting, under scheduled temperature, the hot agglomerate k
asaep on smelting for a certain time in the Resistance Furnace, and the smelting temperature condition is that the temperature increas to melting temperature from 1000℃within 120min, holding for 60min at the melting temperature, after discharge, we must obrve the melting result of the smelting product, one is slag pha rich-mangane slag, the other is metallic pha pig iron. The flowsheet is shown in Fig1.
Rich-mangane slag Pig iron
节目主持人开场白Fig1.The flowsheet of carbon-burdened and cold-bonded pelletizing-electrosmelting process
2. Experiment Principle
The process for smelting rich-mangane slag is the beneficiation of mangane in the slag pha. It contains crystal water’s decomposition at high temperature, the decomposition of carbonate, the lost of oxygen in high valence mangane and the lective reduction of iron and phosphorus in reduction condition, etc. The most esntial is the lective reduction of iron and phosphorus among them.
The smelting principle is that iron, phosphorus and high valence mangane can be reduced adequately and the low valent mangane (MnO) is hard to be reduced under strong reducing condition. Becau of the different reducing condition, the reduced iron, phosphorus and a small amout of mangane enter into condary product mangane, while most mangane exist in slag in the form of MnO, we can parate iron and mangane, improve rich-mangane slag’s Mn/Fe and bring down the P/Mn, finally, achieve the purpos of beneficiation. The reaction equations of smelting principle are shown as follows:
MnO+C=Mn+CO -279470KJ(1370℃)
FeO+C=Fe+CO -158800KJ(685℃)
2P2O5+10 C=4 P+10 CO -1767250 KJ(763℃)
The reduction temperature of iron and phosphorus is lower, when the reduction temperature is below 1350℃. And iron and phosphorus will be reduced and enter molten iron pha, while mangane will enter slag in the form of MnO and react with SiO2. Under such reduction conditions, rich-mangane slag can be obtained. It is specified that the content of mangane is generally 35% ～45%, the iron content is 1.5% ～4.5% and ≤P0.03% in the qualified rich-mangane slag.
3. Experimental Results and Discussion
3.1 Orthogonal test
The tests mainly examine the effect of smelting temperature, reductant dosage, basicity of slag pha and size of raw ore on smelting, and the orthogonal tests are taken. We design experiment according to orthogonal table L9（34）, the test program is showm in Table5 and Table6.
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As shown in Table7, the smelting product is very different under different conditions. Especially when the test condition is level 1, the slag pha and metallographic pha can’t be melted. This suggests that if we want to get better result, the right condition must be chood . The results of recovery analysis range of iron in metallographic pha and mangane in slag pha is shown in Table8. We consider the iron recovery in metallographic pha and Mn recovery in slag pha first when we analy range. According to Table8, in metallographic pha , the influencing factors could be arranged as follows: D ＞A ＞B ＞C, that is the order is size, temperature, basicity and reductant dosage. The most suitable factor combination in metallographic pha is A 2B 3C 2D 3. While in slag pha, the influencing factors
kiss是什么意思could be arranged as follows: B ＞A ＞C ＞D ，that is to say the order is basicity, temperature, reductant dosage and size. The most suitable factor combination in slag pha is A 2B 3C 2D 3. It is obvious that the most suitable factor combination is completely the same,that is temperature is 1410℃, basicity is 0.3, reductant dosage is 1.6% and size is -1mm.
