The oxidation of ilmenite after it was reduced in sulfurcontaining syngas showed an initial brief period of mass gain before a period of mass loss, which was followed by another period of mass gain typical of ilmenite oxidation these initial mass gains and mass losses were attributed to the reactions between the sulfur deposit and air
X ray diffraction and energy dispersive spectroscopy were utilized to follow the progression of ilmenite oxidation at and k and the reduction of pseudobrookite fetio at and k structures formed during the progress of oxidation were related to the systems phase diagrams
Wei lv, yingyi zhang, gangqiang fan, kai tang and xuewei lv, effects of preoxidation and additive on carbothermic reduction of ilmenite concentrate, th international symposium on hightemperature metallurgical processing, , ,
Reduction kinetics of ilmenite ore as an oxygen carrier for methane chemical looping combustion under elevated pressures was studied using a pressurized thermogravimetric analyzer ptga the reduction phase of the experiments was carried out in a mixture of methane and nitrogen with carbon dioxide andor steam to simulate an actual combustion environment the oxidation phase of the
Reduction sequence of ilmenite by carbon in particular, to define the reduction stage during which the majority of the iron oxide is reduced to the alloy phase before any significant reduction of the titanium oxide in the solid state the relative preferential reduction of iron oxides over titanium oxides becomes important pistorius,
Both oxidation and reduction steps affect the grade of the product and a high grade tio is to result oxidation is an exothermic reaction as shown below temperature of oxidation although the oxidation of ilmenite starts at temperatures as low as o c,
The feti system has multiple possible phases those relevant to oxidation and reduction of ilmenite are indicated in figure fe figure feti system the thirteenth international ferroalloys congress efficient technologies in ferroalloy industry ti june , almaty, kazakhstan
The reduction of the iron oxides is not taken to completion so that some iron oxide is left in the slag to decrease its melting point melting point of tio c and ilmenite c the slag is high in titanium and low in iron figure and is therefore preferable to ilmenite
Reduction of titanium from oxidation state to oxidation state occurs above c with reduced atmosphere hence, c is taken as the optimum condition for the reduction studies reduction efficiency with time the reduction efficiency of ilmenite with varying the reduction time min min is given in table
Nov , ilmenite thermally treated at high temperature was used as the oxygen carrier, its oxygen transfer capacity during reduction and oxidation at c was analyzed by tga analysis and using a fixedbed reactor system air was used as oxidizing gas, and vol h was used as reducing gas nonthermally treated ilmenite had low oxygen transfer
In situ analytical tem of ilmenite reduction in hydrogen arne janssen, eric prestat, matthew smith, sarah j haigh and mG burke materials performance centre, school of materials, the university of manchester, manchester, uk ilmenite fetio is an important mineral, formed in igneous and metamorphic rocks, and is the main feedstock for the titanium industry
Hydrogen reduction is one method currently being tested by many universities products of hydrogen reduction are free iron, titanium dioxide tio , and water, which is split to recover the hydrogen and produce oxygen the basic process is to separate ilmenite from lunar soil, crush it to a fine powder to maximize the surface area, and then heat it in an enclosed reaction vessel in the
For pure ilmenite, feii release does not involve a redox reaction however, reductive dissolution can occur if ilmenite forms partial solid solutions with hematite the anodic oxidation of ilmenite results in formation of passivating surface oxidation products most likely pseudorutile
The rusting step the reduced ilmenite is subjected to oxidation by suspending it in nhcl solution followed by aeration when the iron oxide comes out, which can be separated the major disadvantage of the above process is that the rusting is most time consuming
The reduction of natural and preoxidised ilmenite with carbon at temperatures between and k c was studied the reaction was carried out in the atmosphere produced by the gaseous reaction products and the degree of reduction was determined from the co and co contents of the product gas, as measured by chemical absorption and continuous infrared analysis
Reduction of ilmenite to form tio and elemental iron followed by a leach to remove the iron the reduction ilmenite ore by oxidation and magnetic separation followed by leaching with diluted acid kelly and rowson investigated microwave reduction of oxidized
It was found that the oxidation and reduction proceeded topochemically and their kinetic parameters were determined according to the unreacted core shrinking model the mineral composition of the partially oxidized andor reduced ilmenite was examined by means of characteristic xray analysis, the results of which showed that there were two
Reduction of ilmenite to form tio and elemental iron followed by a leach to remove the iron the reduction ilmenite ore by oxidation and magnetic separation followed by leaching with diluted acid kelly and rowson investigated microwave reduction of oxidized
Ilmenite, a natural mineral composed of fetio, is a lowcost and promising oxygen carrier oc for solid fuels combustion in a chemicallooping combustion clc system the aim of this study is to analyze the behavior of ilmenite as an oc in clc and the changes in its properties through redox cycles experiments consisting of reductionoxidation cycles in a thermogravimetric analyzer were
The objective of this study was to establish the kinetic of both reduction and oxidation reactions taking place in the chemicallooping combustion clc process using ilmenite as oxygen carrier because of the beneficial of the use of preoxidized ilmenite and the activation of the ilmenite during the redox cycles, both the reactivity of pre
Oxidation of abu ghalaga and black sand ilmenite ores at various temperatures causes maximum weight increase of approximately and of ilmenite which values correspond to the oxidation of and of their feo into feo, respectively the magnetic proportions of oxidation products increase with rise of temperature up to certain values and then decrease, a fact which was not
Reduction of titanium from oxidation state to oxidation state occurs above c with reduced atmosphere hence, c is taken as the optimum condition for the reduction studies reduction efficiency with time the reduction efficiency of ilmenite with varying the reduction time min min is given in table
The rutile will be tan or brown, the ilmenite will be black or dark brown likewise, under a microscope the ilmenite will be an opaque black whereas the rutile crystals will be somewhat translucent or transparent ilmenite can be used in small amounts to produce dark brown specks in
Oxidation states of the upper mantle recorded by megacryst ilmenite in kimberlite and type a and b spinel lherzolites rJ arculus , jB dawson , rH mitchell , dA gust , and rD holmes and the reduced states found in upper man tlederived rock types, sato suggested that hoss
The oxidation at c for h yielded a content of of tio , and the highest oxidation of ilmenite was achieved at , c for h the carbothermic reduction with wt carbon at
A process for enhancing ilmenite from deposits of mineral sands or mineral concentrates comprises a single stage fluidized bed magnetizing roast a temperature of c c in an excess of a carbonaceous fuel such as coalchar, co or hydrocarbon is used to provide an atmosphere in which the oxygen potential is controlled resulting in a consistently high magnetic susceptibility
The presence of chromite in significant amount in ilmenite downgrades the market value of the ilmenite a substantial amount of the chromite may be removed, firstly by a reduction step, secondly by a leaching, aeration or oxidation roasting step and finally by a physical separation step an optional preoxidation may precede the reduction step and an optional physical separation step may be
The oxidation of ilmenite ore is used in titanium processing the effects of oxidation conditions, namely, temperature, ilmenite particle size, and oxygen pressure, on the product phase were
A process for producing ferrotitanium by aluminothermic reduction, including reacting reduced ilmenite comprising a solid matrix of substantially metallic iron microparticles in titanium dioxide with aluminium at a temperature whereby titanium dioxide constituents of the reduced ilmenite are exothermically reduced to titanium metal to provide a reaction melt product also containing aluminium
Oxygen fugacities of olivineorthopyroxeneilmenitebearing, highpressure megacrysts, mineral intergrowths, and peridotites from kimberlites and from a minette have been calculated from the equilibrium fe o fesio fesi o o Resultant fo s, which are interpreted to reflect the subcontinental source regions of alkalic magmas, are clustered between the quartz
The results indicated that after the oxidation roasting up to c, the flotation behavior of ilmenite was greatly improved across a wide ph range the maximum increase in ilmenite flotation recovery was about at ph values ranging from to after the roasting of ilmenite at c, ilmenite was floated with a recovery of at
Reduction of ilmenite is possible with coke at e shomate et al carried out a thermodynami c study of reduction of ilmenite by carbon, carbon monoxide and hydrogen yijay et ai studied preoxidation and hydrogen reduction of ilmenite in a fluidized bed reactor in a kinetic study on the reduction of ilmenite
The oxidation of ilmenite fetio in air and dry oxygen was investigated over the temperature interval to c dense platelets of ilmenite crystals as well as powder samples of ilmenite were oxidized the weight data were recorded employing a thermobalance the oxidation kinetics of ilmenite platelets were parabolic except for the initial stages during which logarithmic kinetics were
