Kinetics of Evaporation of Zn and Pb from Carbon-bearing Pellets Made of Dust Containing Zn-Pb-Fe Oxides

The influence of reduction temperature, size of coal powder and the carbon content on the evaporation rates of Zn and Pb in pellets made of ZnO-PbO-FeO bearing dust has been investigated between 1100-1300℃. The evaporation rate of Zn and Pb obtained from the experiments has been analyzed with kinetic models. The results show that the control step for evaporation of Zn is reduction reaction of ZnO by CO at the interface，and that the evaporation rate of Pb is controlled by the volatilization of reduction products, i.e. liquid lead. The overall apparent activation energies of Zn and Pb evaporation from the pellet are 79.42kJ/mol and 88.74kJ/mol respectively.

Study on the volatilization kinetics of lead in carbon- containing pellets made of Zn- Pb- bearing dusts

This study investigated the volatilization kinetics of lead in pellets made of Zn-Pb-bearing dusts mixed with coal powder,in a nitrogen atmosphere and in the temperature range between 1 100 ℃ - 1 300℃ ,and showed that the reduction temperature has a significant effect on the volatilization rate of lead and that neither the particle size of the coal powder nor the extra carbon content has any effect on the volatilization rate. The obtained activation energy for the volatilization of lead is 88.74 kJ/mol. The volatilization rate of lead is controlled by both the lead evaporation reaction and the diffusion of gaseous lead through the gas boundary layer covering the surface of the reduced liquid lead.

Study on the volatilization kinetics of zinc in carbon-containing pellets made of Zn-bearing dusts

A study was carried out on the volatilization kinetics of Zn in the pellets made of Zn-bearing dusts mixed with coal powder in a nitrogen atmosphere and within the temperature range between 1 100℃and 1 300℃. The study shows that the reduction temperature has a significant effect on the volatilization rate of zinc and that either the coal particle size or the excess carbon content has no effect on the volatilization rate. The obtained activation energy for the volatilization of zinc is 79.42 kJ/mol. The volatilization rate of zinc is controlled by the reaction between the zinc oxides and CO.

Beneficiation of Titanium Oxides From Ilmenite by Self-Reduction of Coal Bearing Pellets

The study on the beneficiation of titanium oxides from Panzhihua ilmenites by reduction of coal bearing pellets was carried out. The iron oxides in pellets were efficiently reduced to metal iron, and titanium oxide slag beneficiated was separated from metal iron. The effect of temperature, flux and coal blending ratio on the reduction and separation was investigated, and rational parameters were determined. A new process for the beneficiation of titanium oxides by rotary hearth furnace （RHF） was proposed.

Effect of Cr/Mn segregation on pearlite–martensite banded structure of high carbon bearing steel

The effect of Cr/Mn segregation on the abnormal banded structure of high carbon bearing steel was studied by reheating and hot rolling.With the use of an optical microscope, scanning electron microscope, transmission electron microscope, and electron probe microanalyzer, the segregation characteristics of alloying elements in cast billet and their relationship with hot-rolled plate banded structure were revealed.The formation causes of an abnormal banded structure and the elimination methods were analyzed.Results indicate the serious positive segregation of C, Cr, and Mn alloy elements in the billet.Even distribution of Cr/Mn elements could not be achieved after 10 h of heat preservation at 1200℃, and the spacing of the element aggregation area increased, but the segregation index of alloy elements decreased.Obvious alloying element segregation characteristics are present in the banded structure of the hot-rolled plate.This distinct white band is composed of martensitic phases.The formation of this abnormal pearlite–martensite banded structure is due to the interaction between the undercooled austenite transformation behavior of hot-rolled metal and the segregation of its alloying elements.Under the air cooling after rolling, controlling the segregation index of alloy elements can reduce or eliminate the abnormal banded structure.

Hydrochar Pelletization towards Solid Biofuel from Biowaste Hydrothermal Carbonization

Hydrothermal carbonization is highly applicable to high moisture biomass upgrading due to the fact that moist-ure involved can be directly used as reaction media under the subcritical-water region.With this,value-added utilization of hydrochar as solid fuel with high carbon and energy density is one of the important pathways for biomass conversion.In this review,the dewatering properties of hydrochar after the hydrothermal carbonization of biowaste,coalification degree with elemental composition and evolution,pelletization of hydrochar to enhance the mechanical properties and density,coupled with the combustion properties of hydrochar biofuel were discussed with various biomass and carbonization parameters.Potential applications for the co-combustion with coal,cleaner properties and energy balance for biowaste hydrothermal carbonization were presented as well as the challenges.

KINETICS OF CARBON OXIDATION IN CARBON-BEARING REFRACTORIES

ＫＩＮＥＴＩＣＳＯＦＣＡＲＢＯＮＯＸＩＤＡＴＩＯＮＩＮＣＡＲＢＯＮＢＥＡＲＩＮＧＲＥＦＲＡＣＴＯＲＩＥＳ①ＬｕｏＸｉｎｇｙｕａｎ，ＱｉａｏＺｈｉｙｕ，ＹａｎｇＴｉａｎｊｕｎＤｅｐａｒｔｍｅｎｔｏｆＰｈｙｓｉｃａｌＣｈｅｍｉｓｔｒｙ，Ｕｎｉｖｅｒｓｉ...

Carbon Segregation of Bearing Steel Concasting Billet

The formation mechanism of 'white band' and central carbon segregation of high-carbon Cr bearing steel concasting billets are discussed in this paper. The maximum oxygen content in the steel produced by concasting process was 13xl0^-6 with an average oxygen content of 9.3xl0^-6. Comparison of metallurgical quality and fatigue property between the concasting steel (CC) and ingot casting steel (IC) showed that the carbon segregation (C/C0) in former steel was 0.92～1.10 and its fatigue life was equal to that of the latter steel.

Effect of Cr2O3 addition on oxidation induration and reduction swelling behavior of chromium-bearing vanadium titanomagnetite pellets with simulated coke oven gas

The oxidation induration and reduction swelling behavior of chromium-bearing vanadium titanomagnetite pellets(CVTP)with Cr2O3 addition were studied,and the reduction swelling index(RSI)and compressive strength(CS)of the reduced CVTP with simulated coke oven gas(COG)injection were investigated.The results showed that the CS of the CVTP decreases and the porosity of the CVTP increases with increasing amount of Cr2O3 added.The Cr2O3 mainly exists in the form of(Cr,Fe)2O3 solid solution in the CVTP and as Fe-Cr in the reduced CVTP.The CS of the reduced CVTP increases and the RSI of the reduced CVTP decreases with increasing amount of Cr2O3 added.The limited aggregation and diffusion of metallic iron contribute to the formation of dense lamellar crystals,which leads to the slight decrease for reduction swelling behavior of reduced CVTP.This work provides a theoretical and technical basis for the utilization of CVTP and other Cr-bearing ores such as chromite with COG recycling technology.

In vitro evaluation of a new resilient, hard-carbon, thin-film coating as a bearing material for ventricular assist devices ——In Vitro Bearing Evaluation of BioMedFlex

Our aim was to evaluate the potential use of BioMedFlex? (BMF), a new resilient, hard-carbon, thin- film coating, as a blood journal bearing material in Cleveland Heart’s continuous-flow left and right ven- tricular assist devices (VADs). BMF is not classified as a diamond-like carbon (DLC) and differs from other thin-film carbon coatings by its high flexural strength, radiopacity, and wear resistance. A 2- to 4-μm-thick BMF adhesion layer was deposited on the VAD journal bearing surfaces. A commercial DLC coating used in other clinical blood pump applications was used as a control. Durability and reliability of the BMF coating was verified in severe pump start/stop testing using 20 BMF-coated journal bearing pairs. The BMF-coated surfaces showed no coating failures, whereas 57% of the DLC bearing pairs developed scratches through the carbon coating, documenting that BMF can provide a durable coating in our blood journal bearing application. In conclusion, BMF has shown qualities that support its significant advantages as an alternative journal bea- ring material in Cleveland Heart pumps. Our plan includes biocompatibility testing with ongoing animal studies, endurance testing with submerged pumps running in saline, and assessment of batch coating processing capability.

Chemical Analysis Method for Carbon Bearing Refractory Products——Determination of the Total Carbon by Combustion Gravimetric Method

GB/T 13245-91 1 Theme and Scope This standard specifies the method abstract, reagents, apparatus, specimen, analyzing procedure, result calculation and permissible tolerance used for determination of the total carbon with combustion gravimetric method.

Effect of tempering temperature on the mechanical properties and microstructure of an copper-bearing low carbon bainitic steel

The effect of tempering temperature on the microstructure and mechanical properties of ultra-high strength, copperbearing, low-carbon bainitic steel has been investigated in the experiment. The results showed that the microstructure was mainly the laths of bainite in the as-quenched steel. The bainitic laths were restored and combined after the steel tempered at various tempera- tures. There were rnartensite/austenite （M/A） islands and numerous dislocations within and between the bainitic laths, while very t-me precipitates of ε-Cu were also observed within the laths. With increasing the tempered temperature from 400 to 600℃, the yield strength （YS） increased from 877 to 957 MPa, whereas the ultimate tensile strength （UTS） decreased from 1020 to 985 MPa. The Charpy V-notch （CVN） varied from 68.5 to 42 J, and the value was minimal for the steel tempered at 500℃. 2008 University of Science and Technology Beijing. All rights reserved.

Experimental Study on Hydrocarbon Formation Due to Reactions Between Carbonates and Water or Water Bearing Minerals in Deep Earth

In order to investigate the mechanism of formation of abiogenetic hydrocarbons at the depth of the Earth, experimental research on reactions between carbonates and water or water bearing minerals was carried out at the pressure of about 1 GPa and the temperature range of 800-1500℃. The reactions took place in an open and nonequilibrium state. Chromatographic analyses of the gas products indicate that in the experiments there were generated CH 4 dominated hydrocarbons, along with some CO 2 and CO. Accordingly, we think there is no essential distinction between free state water and hydroxy in the minerals in the process of hydrocarbon formation. This study indicates that reactions between carbonates and water or water bearing minerals should be an important factor leading to the formation of abiogenetic hydrocarbons at the Earth’s depth.

Reduction of Panzhihua titanium-bearing oxidized pellets by CO-N_2-H_2 gas

The effect of H_2 gas content on the reduction of Panzhihua titanomagnetite concentrate pellets by carbon monoxide was investigated by isothermal reduction experiment using CO-N_2-H_2 gas mixtures in a vertical electric resistance furnace.The morphology and phase transformation of reduced samples obtained were detected by scanning electron microscopy,energy disperse spectroscopy analysis and X-ray diffractometry respectively.The results show that increasing H_2 content will enhance the initial stage of reduction rate apparently.There are two reasons responsible for this effect,one is that H_2 accelerates the chemical reaction,and the other is that the addition of H_2 gas can improve the porosity of pellet intensively.It is noteworthy that this effect is more obvious when the reduction temperature reaches 1473 K with sticking phenomenon happening.There are no crystalline phases which can be found such as ulvospinle,ilmenite,ferrous-pseudobrookite and any titanium oxide except titanomagnetite(TTM).The reduction progress is suggested as follows:1) Fe_2O_3→Fe_3O_4→FeO→Fe;2) Fe_2TiO_5→Fe_2TiO_4+Fe_3O_4→TTM.Element Al migrates and gets enriched in high titanium content iron ores,and eventually Al to Ti molar ratio is 1:3.Al is likely to dissolve in titanium iron oxides to form a kind of composite iron compound,which results in the restrain of reduction.

Diamond-like carbon films synthesized on bearing steel surface by plasma immersion ion implantation and deposition

Diamond-like carbon (DLC) films were synthesized by plasma immersion ion implantation and deposition (PIIID) on 9Cr18 bearing steel surface. Influences of working gas pressure and pulse width of the bias voltage on properties of the thin film were investigated. The chemical compositions of the as-deposited films were characterized by Raman spectroscopy. The micro-hardness, friction and wear behavior, corrosion resistance of the samples were evaluated, respectively. Compared with uncoated substrates, micro-hardness results reveal that the maximum is increased by 88.7%. In addition, the friction coefficient decreases to about 0.1, and the corrosion resistance of treated coupons surface are improved significantly.

Chemical Analysis Method for Carbon Bearing Refractory Products——Determination of Magnesium Oxide Content by CyDTA Volumetric Method

This standard specifies the method summary, reagents, apparatus, sampling, procedure, test results calculation and permissible tolerance of the determination of magnesium oxide by CyDTA volumetric method.

Analysis and application of carbon-bearing rate of reservoirs in the Puguang gas field,northeastern Sichuan Basin

With wells Puguang 2 and 6 in the Puguang gas field as the research objects by choosing organic carbon as characterization reservoir carbon(indirectly reflecting the bitumen contents),this paper discusses the relationship between bitumen contents and lithologic characteristics,reservoir characteristics,and calculates the volume of paleo-oil and oil cracked gas.The study shows that the organic carbon contents of the reservoirs are related to lithologic characteristics.Due to variations in the particle size or structure of rocks,the porosity of the reservoirs varies,furthermore,it will influence the contents of organic carbon.And the relationship between these two parameters is positive.Based on the analysis,the relationship between total organic carbon(TOC)and the contents of reservoir bitumen also appears to be positive.The volume of paleo-oil and cracked gas of the Changxing-Feixian’guan Formation are respectively 495 million tons and 360.4 billion m3 through the calculation of reservoir’s organic carbon.Therefore,the relationship between carbon-bearing rate and characteristics of the reservoirs can be used to indirectly evaluate reservoir types.Besides,the carbon-bearing rate of the reservoirs also reflects the contents of reservoir bitumen,paleo-oil as well as natural gas.It makes a new approach for the study of the types of reservoirs and the amounts of paleo-oil and oil cracked gas in northeastern Sichuan Basin.

The Treatment of Polymer-bearing Wastewater from Refinery by Fenton Oxidation - Activated Carbon Adsorption

To solve the problem of polymer-bearing effluent of crude oil not reaching the standard,deep treatment system of Fenton oxidation-activated carbon adsorption is established in one refinery,and the most suitable condition of Fenton oxidation reaction is determined.Operation results show that CODCrconcentration of effluent treated by the system could be lower than 50 mg/L,and ammonia nitrogen content is less than 3 mg/L,which meets design requirement.

Effects of Catalyst and Additive Containing Li, Na, or Ca on Reduction of Iron Oxide/Carbon Composite Pellets

The catalyst containing 0.69% (mass fraction) of Li+, Na+, or Ca2+ were synthesized, and the catalytic effect on the reduction of iron oxide/carbon composite pellets were investigated by comparing with that of additive at 850 degreesC. The effect of the catalyst was greater than that of the additive, it can be considered that catalyst promoted the formation of iron nucleus early on reduction processes of iron oxide/carbon composite pellets. In addition, both effects of catalyst and additive increased after added carbon powder into the pellets, but the extent of increase decreased when the carbon powder exceeded a suitable content (about 4%), this amount is less than that of carbon needed theoretically on the reduction from hematite to iron.

Effect of CaO and CaCO3 on Reduction Rate of Iron Ore Pellets Containing Carbon

The effect of metallurgical fluxes CaO and CaCO3 on the reduction rate of iron ore pellets containing carbon in nitrogen atmosphere has been studied by a weight-loss thermal balance. The experimental results showed that adding CaO or CaCO3 can promote reduction reaction as the added CaO or CaCO3 probably decrease the apparent activation energy of iron ore concentrate-carbon-CaO or CaCO3 reaction, and the reduction rate constant changes with mass percent of CaO and CaCO3. The kinetic analysis also showed that the rate-controlling step of the reaction is inner gas diffusion.