Clean production of Fe-based amorphous soft magnetic alloys via smelting reduction of high-phosphorus iron ore and apatite

Separated preparation of prealloys and amorphous alloys results in severe solidification-remelting and beneficial element removal-readdition contradictions,which markedly increase energy consumption and emissions.This study offered a novel strategy for the direct production of FePC amorphous soft magnetic alloys via smelting reduction of high-phosphorus iron ore(HPIO)and apatite.First,the thermodynamic conditions and equilibrium states of the carbothermal reduction reactions in HPIO were calculated,and the element content in reduced alloys was theoretically determined.The phase and structural evolutions,as well as element migration and enrichment behaviors during the smelting reduction of HPIO and Ca_(3)(PO_(4))_(2),were then experimentally verified.The addition of Ca_(3)(PO_(4))_(2)in HPIO contributes to the enrichment of the P element in reduced alloys and the subsequent development of Fe_(3)P and Fe_(2)P phases.The content of P and C elements in the range of 1.52 wt% -14.63 wt% and 0.62 wt% -2.47 wt%,respectively,can be well tailored by adding 0-50 g Ca_(3)(PO_(4))_(2)and controlling the C/O mole ratio of 0.8-1.1,which is highly consistent with the calculated results.These FePC alloys were then successfully formed into amorphous ribbons and rods.The energy consumption of the proposed strategy was estimated to be 2.00×10^(8) kJ/t,which is reduced by 30% when compared with the conventional production process.These results are critical for the comprehensive utilization of mineral resources and pave the way for the clean production of Fe-based amorphous soft magnetic alloys.

Recovery of valuable metals from spent lithium ion batteries by smelting reduction process based on FeO-SiO_2-Al_2O_3 slag system

NA novel smelting reduction process based on FeO-SiO2-Al2O3 slag system for spent lithium ion batteries with Al cans was developed, while using copper slag as the only slag former. The feasibility of the process and the mechanism of copper loss in slag were investigated. 98.83% Co, 98.39% Ni and 93.57% Cu were recovered under the optimum conditions of slag former/battery mass ratio of 4.0：1, smelting temperature of 1723 K, and smelting mass ratio of time of 30 min. The FeO-SiO2-Al2O3 slag system for the smelting process is appropriate under the conditions of m（FeO）：m（SiO2）=0.58：1？1.03：1, and 17.19%？21.52% Al2O3 content. The obtained alloy was mainly composed of Fe-Co-Cu-Ni solid solution including small amounts of matte. The obtained slag mainly consisted of fayalite and hercynite. Meanwhile, the mechanism of copper loss is the mechanical entrainment from strip-like fayalite particles in the main form of copper sulfide and metallic copper.

Mixture of ilmenite and high phosphorus iron ore smelted by oxygen-enriched top-blown smelting reduction

In order to reasonably utilize the abundant resources of high-phosphorus iron ore and ilmenite in China, the technology of top-blown smelting reduction with oxygen enrichment was used to smelt the mixed ore of high-phosphorus iron and ilmenite. The effect, which is related to basicity, reduction temperature, carbon-oxygen ratio and time of ventilated oxygen to iron recovery, dephosphorization rate, content of iron, phosphorus, sulfur and titanium in pig iron, was investigated in the experiment. The results show that an ideal outcome can be gained in condition of 6：4 ration on Mengqiao concentrate and Huimin iron ore, temperature of 1 500℃, basicity of 1.3, 1.0 on molar ration of carbon to oxygen, time of 10 min on blowing-oxygen. The outcome is that there is no foamy slag in generation, a good separation of slag and iron, iron recovery with 91.41%, content of phosphorus with 0.27% and tilanium content less than 0.001%, The atmosphere of strong oxidizing in the upper of reduction container and high potential of oxygen in the composition of slag in this technique bring phosphorus, titanium and silicon into slag, which ensures less content of impurity in pig iron.

Reduction Rate of Ferrous Oxide in Smelting Reduction

Reduction rate of ferrous oxide in smelting reduction with iron bath has been studied. The main affecting factors on reduction rate, such as composition of the melt, temperature of molten bath, basicity of slag and the way of supplying carbonaceous materials have also been investigated.

CLEAN PRODUCTION AND SMELTING REDUCTION TECHNOLOGY

Clean Production is the best method for iron-steel making industry to eliminate pollution thoroughly. In order to achieve this object, smelting reduction technology should play the key role. Furthermore, process integration method can be used to solve the problem of residual gas utilization by integrating smelting reduction process with direct reduced iron unit, gasoline, methanol or dimethyl ether synthesis unit, etc. A new smelting reduction process has been proposed which can be constructed on the present plant site. Since this process can directly treat the lump coal and iron ore fines, it reduces st6ps necessary in traditional blast furnace process and Corex smelting reduction process.

THERMODYNAMICS OF V REDUCTION IN SMELTING REDUCTION SLAG FOR V-Ti-CONTAINING MAGNETITE

For slag system of CaO-SiO_2-Al_2O_3-MgO-V_2O_5,the time of V reduction to appro ch the dynamical equilibrium is about 6 h,the equilibrium time is not evidently influenced by the ratio CaO/SiO_2 and shortens with the increase of temperature.It the ratio of the weight of slag to that of iron bath is 1/2,CaO/SiO_2 0.8 and tomperature 1773 K.the maxium distribution coefficeent of V reduction is 32.4 and maxium recovery of V is 96.1%.

COMBINED TECHNOLOGY OF SMELTING REDUCTION IRON-MAKING AND CLEAN FUEL MANUFACTURE

Smelting reduction is a front iron making technology for the 21st century. It can produce liquid iron by direct using common coal but not charred coal. The process has many attractive advantages such as concise flow, low investment and production cost, low environmental pollution and high quality molten iron. Combined with a reciprocal chemical technology, energy efficiency can be further improved by transforming mass coal gas, by-produced in smelting reduction,into dimethyl ether, a clean fuel. Method and characteristics of the combined technology are discussed in this paper.

STUDY OF SMELTING REDUCTION RATE FOR VANADIUM TITANIUM MAGNETITE

A comparative study was made of the reduction kinetics for high temperature smelting of vadium-titanium-containing magnetite,together with Hainan iron ore,using iron bath method.Three peaks were revealed on the reduction rate curves for the magnetite,while one peak only for Hainan ore.Under the same conditions,the smelting reduction rate of the magnetite was found to be lower than that of Hainan ore.The rate increases evidently with the increase of the bath volume.The expressions of smelting reduction rate were suggested for the reduction with and without iron bath respectively.

Laboratory Investigation of Zinc Recovery fromEAF Dust by Bath Smelting Reduction

Bath smelting reduction for recovering zinc from EAF (Electric Arc Furnace) dust has been investigated in the laboratory. A degree of zinc volatilization of more than 99% was obtained from the process. Temperature has a clear influence on the reduction rate of ZnO in slag. The reduction rate of (ZnO) by [C] is the first order with respect to the content of ZnO in the slag. The apparent activation energy of the (ZnO) reduction reaction is 312 kJ/mol at 1300-1500℃.

Corrosion Resistance of High-Alumina Graphite Based Refractories to the Smelting Reduction Melts

The corrosion resistance and microstructure of Al2O3-C based refractories in smelting reduction melts were studied and evaluated by the quasi-stationary immersion and rotary immersion test. The corrosion rate of the Al2O3-C based refractories is decreased with the addition of the graphite carbon and ZrO2. The test results showed that the ZrO2 containing bricks had much better corrosion resistance than the ZrO2- free bricks. The ZrO2 addition improved the oxidization resistance of the refractory and decreased the interaction rate between the melts and the refractory. The corrosion of the Al2O3-C based refractories is caused by both the interaction between melts and refractory and the dissolution of the refractory constituents into the melts.

Corrosion of Magnesia-chrome Brick by Smelting Reduction Slag with Iron Bath

Effects of FeO content （0, 5%, 10%, and 15% in mass, respectively ） in lab-synthesized smelting redttc- tion slag with iron bath and test temperature （1 450, 1 500, 1550, anti 1 600 ℃ ） on corrosion am,amount and microstructure of fused rebonded magnesia - chrome brick with 26.02 massqc of Cr2O3 were researched by rotary cylinder method. The results show that ： （ 1 ） the corro- sion amolult of magnesia -chrome brick by slag without FeO is higher than that by the slag with 5% FeO, and the vorrosion amount increases when FeO content increa- ses from 5% to 15% ; （2） the test temperature is one of the important factors affecting the slag corrosion resist- ance of magnesia - chrome brick, and the corrosion of smelting reduction slag to brick increases with the temperature rising.

Enrichment and reconfiguration of titanium-bearing phase in vortex smelting reduction process of vanadium-titanium magnetite

To comprehensively utilize the low-iron high-vanadium-titanium magnetite,a new method of vortex smelting reduction of vanadium-titanium magnetite was proposed,and the enrichment and reconstitution regularity of Ti-bearing phases in the slag was investigated through X-ray fluorescence spectrometry,X-ray photoelectron spectroscopy,X-ray diffraction analysis,and optical microscopy.The phase diagram revealed that the preferential crystallization of MgTi_(2)O_(5) can be achieved by adjusting the CaO,MgO,and TiO_(2) contents of slag.The predominant Ti-bearing phases in the slag obtained from the reduction process are MgxTi_(3_x)O_(5)(0≤x≤1)and CaTiO_(3).FeTiO_(3) is present at carbon-iron ratio(CR)=1.3,while MgTi_(2)O4 and TiC are formed at CR=1.3.The enrichment of TiO_(2) in the slag increases first and then decreases as the CR increases,and at CR=1.1,the enrichment of TiO_(2) in the slag reaches 51.3 wt.%.Additionally,the concentrations of MgxTi_(3_x)O_(5)(0≤x≤1)and CaTiO_(3) in the slag,along with the grain width of MgxTi_(3_x)O_(5)(0≤x≤1),decrease with the increase in CR.

Recovery of cobalt from converter slag of Chambishi Copper Smelter using reduction smelting process

The reduction smelting process for cobalt recovery from converter slag of the Chambishi Copper Smelter in Zambia was studied. The effects of reducing agent dosage, smelting temperature and time and the addition of slag modifiers （CaO and TiO2） were investigated. In addition, the depleted slag and cobalt-bearing alloy were characterized by X-ray diffraction, scanning electron microscopy and energy dispersive spectroscopy. Under the determined conditions, 94.02% Co, 95.76% Cu and less than 18% Fe in the converter slag were recovered. It was found that the main phases of depleted slag were fayalite and hercynite; and the cobalt-bearing alloy mainly contained metallic copper, Fe-Co-Cu alloys and a small amount of sulfide.

Ilmenite Smelted by Oxygen-Enriched Top-Blown Smelting Reduction

Total ilmenite from Yunnan, China, difficult to smelt in blast furnace, was smelted by oxygen-enriched top-blown smelting reduction ironmaking technology. Much more details on smelting were discussed. Specifically, the influence of reduction temperature, slag basicity and molar ratio of carbon to oxygen on the reduction quality level including iron recovery and titanium and sulfur contents in the pig iron produced in the experiment was investigated. Iron recovery rate could reach 95 % with titanium content below 0.05 % in pig iron produced, under the conditions of holding time of 30 min at 1 823 K, basicity of 1.1, carbon to oxygen molar ratio of 1.0 and oxygen enriched flow rate of 250 L/h. Oxidization potential of top-space of smelting reduction vessel and slag combination could create the driv ing force to partition phosphorous, titanium and silicon into the slag, which ensured low contents of the impurities involved above and carbon in pig iron. In addition, it avoided the generation of Ti（C,N） that could reduce interracial tension of slag, which induced the formation of foaming slag seriously. Furthermore, jam of chargings and bubble flooding would be triggered, resulting in deterioration of BF state, increase of iron loss and decline of desulfurization rate.

Influence of laterite nickel ore on extracting iron from Bayer red mud by carbothermal smelting reduction

In view of the difficulty of extracting iron from Bayer red mud,a new idea of adding laterite nickel ore into red mud was proposed to prepare a high value-added product.Toward this,the influences of laterite nickel ore on thermodynamic reaction,slagging and smelting reduction of extracting iron from red mud were studied.The results indicated that the product of extracting iron from red mud(R100)was changed with the addition of laterite nickel ore(R70L30).The slag of R100 was strongly basic,while the R70L30 was weakly acidic with composition closer to the ideal blast furnace slag.The metal recovery of R100 was 75.16%and that of R70L30 was 94.05%.At the same temperature,the slag viscosity of R70L30 was significantly lower than that of R100,which proved that laterite nickel ore can adjust the basicity,reduce melting point of slag and improve metal recovery.Because Fe,Ni and Cr in red mud and laterite nickel ore can be reduced sufficiently,a low Ni–Cr alloy cast iron can be directly prepared.

Study on Foaming Behaviour of Molten Slag during Smelting Reduction with Iron Bath

The molten slag in smelting reduction with iron bath has peculiar behaviour for its high FeO concentration. Slag foaming is effected by the concentration and reduction rate of FeO, basicity of slag and temperature. Addition of granulated coke can greatly decrease slag foaming extent in the process of smelting reduction with iron bath. The anti-foaming capacity of granulated coke is the best when the ratio of coke used for coke layer to total coke used in smelting reduction is controlled at about 20%.

A Coupling Dynamic Model for Dissolution and Reduction of Chromium Ore in a Smelting Reduction Converter

For describing and resolving the process of chromium ore smelting reduction in a converter preferably, the coupling dynamic model was established based on the kinetic models of chromium ore dissolution and interfacial re- ducing reaction between the slag and metal. When 150 t stainless steel crude melts with chromium of 12% are produced in a smelting reduction converter with no initial chromium in metal at 1 560℃, the results of the coupling dynamic model show that the mean reduction rate and injection rate of chromium ore are 0. 091% ·min^-1 and 467 kg · min^-1 , respectively. The foundation of the coupling dynamic model provides a reference and basis on the constitution of rational processing route for a practical stainless steelmaking.

Experimental study on smelting reduction of carbon-bearing manganese briquettes in slag bath

The reduction of carbon-bearing manganese briquettes in a slag bath was experimentally investigated at temperatures ranging from 1550 to 1650 ℃. Both the internal temperature and the microstructure evolution of the briquettes were analyzed by differential thermal analysis, scanning electron microscopy and energy-dispersive spectrum analysis, and the smelting reduction mechanism of the carbon-bearing manganese briquettes in the slag bath was further elaborated. The results indicated that the smelting reduction of the briquettes in the slag bath could be divided into three stages, and the aggregation and growth of the metallic particles during the reduction were significantly affected by the slag temperature. Under the experimental conditions, the reduction speed at the initial stage of the carbon-bearing manganese briquettes smelting reduction was controlled by the chemical reaction, whereas the reaction speeds at both the middle and following stages were limited by gaseous diffusion.

Physical simulation of mixing on a C-H2 smelting reduction reactor with different tracer feeding positions

With the growing demand for energy saving,emission reduction,and green metallurgy,we had designed a new C-H2 smelting reduction reactor.In order to solve the key problem that the heat transfer efficiency from high temperature oxidation zone in upper region to low temperature reduction zone in lower region is low in traditional metallurgical reduction reactor,a water simulation was adopted to optimize the mean residence time and to improve the transmission efficiency within the reactor.According to the modified Froude similarity,a water model experimental reactor with a ratio of 1:1 to the prototype was constructed.In the prototype,the feed port was used to feed preheated ore and flux.In order to simulate the effect of different feeding positions of the tracer on the mixing behavior in the molten pool,four points of tracer feeding position were arranged for a systematic study.At the same time,based on double-row side nozzle with thick slag layer in a C-H2 smelting reduction reactor,nine influencing factors,including relative angle between upper and lower side nozzles,were studied.The experimental results showed that the tracer feeding position had a great influence on the mean residence time,and the relative angle also had a great influence on tracer feeding position.Finally,through comprehensive analysis,the optimal condition parameters were obtained under different tracer feeding positions.These results provide valuable help for the design and optimization of the C-H2 smelting reduction reactor.

Fundamental Research of Making Stainless Steel by Smelting Reduction of Chromite

Two processes of making stainless steel in electric furnace- AOD furnace and converter furnace- AOD furnace by using chromite are suggested.The analysing and computing results show that the energy consumption and cost of the processes suggested are lower than those of the traditional process by using ferrochrome.The crude stainless steel liquid with chromium content of 15% is obtained in hot mode experiment of chromite reduction.The kinetics of chromite reduction is discussed according to the experiment results.The relations of pre-reduction rate and smelting reduction rate of chromite with the factors that affect the reduction rate are derived.