Effect of pyroxenite and olivine minerals as source of MgO in hematite pellet on improvement of metallurgical properties

Pelletization of hematite ore requires high fineness and very high induration temperature（~1325 ℃） owing to its poor diffusion bonding unlike magnetite ore. Further, high-alumina hematite pellets show very high reduction degradation index（RDI） during low temperature（500-650 ℃） reduction due to their volume expansion and lattice distortion. Noamundi（India） hematite ore contains very high Al2O3（2.3%） with adverse ratio of alumina to silica（~2） for which, it shows very high RDI. In this work, the acid pellets prepared from Noamundi ore fines of optimum Blaine fineness show good cold crushing strength（CCS）. However, it shows very high RDI（77%）. In order to reduce RDI, Mg O in form of two different gangue-containing fluxes, such as pyroxenite and olivine in varying quantities has been added. The optimum requirement and performance of these fluxes has been examined and compared. Both pyroxenite and olivine fluxed pellets show significant lowering of RDI（26% and 23%, respectively） and improvement of other properties, viz CCS, swelling indices etc with good reducibility（70%-77%）. Finally, a good quality acidic hematite pellet was developed from high-alumina ore without using any lime which is very important charge material in combination of basic sinter in blast furnace.

Development of carbon composite iron ore micropellets by using the microfines of iron ore and carbon-bearing materials in iron making

Iron ore microfines and concentrate have very limited uses in sintering processes. They are used in pelletization; however, this process is cost intensive. Furthermore, the microfines of non-coking coal and other carbon-bearing materials, e.g., blast-furnace flue dust （BFD） and coke frees, are not used extensively in the metallurgical industry because of operational difficu]ties and handling problems. In the present work, to utilize these microfines, coal composite iron oxide micropellets （2-6 mm in size） were produced through an innovative technique in which lime and molasses were used as binding materials in the micropellets. The micropellets were subsequently treated with CO2 or the industrial waste gas to induce the chemical bond formation. The results show that, at a very high carbon level of 22wt% （38wt% coal）, the cold crushing strength and abrasion index of the micropellets are 2.5-3 kg/cm2 and 5wt%-9wt%, respectively; these values indicate that the pellets are suitable for cold handling. The developed micropellets have strong potential as a heat source in smelting reduction in iron making and sintering to reduce coke breeze. The micropellets produced with BFD and coke fines （8wt%-12wt%） were used in iron ore sin- tering and were observed to reduce the coke breeze consumption by 3%-4%. The quality of the produced sinter was at par with that of the conventional blast-furnace sinter.

通过C02处理开发用于碱性氧气转炉炼钢的氧化铁球强化熔剂

目前在碱性氧气转炉炼钢过程中，采用石灰块作为熔剂原料。然而实际操作中，由于其熔点较高、溶解性能差、产生细粉并且具有较强的吸水性，通常会遇到一些问题。CaO含量为22％的CaO—Fe2O3二元系具有一个共晶点（1200℃），因此在BOF吹炼的开始阶段，由石灰和氧铁组成的烧结体将会产生低熔点的氧化性炉渣，并且使精炼过程变得容易。在此研究中，采用废弃的氧化铁准备由氧化铁和石灰组成的熔剂，并且开发了在室温条件下，通过含有CO2／CO2的气体处理对其进行强化，而不是单独地采用粘结剂、工业废气，也就是说，高炉气体（BFG）可能是CO2合适的气源。通过像冷抗压强度、落差强度、耐磨强度等物理性能优化造球过程的加工参数，例如球的组成、铁矿粉的颗粒尺寸、处理条件等。直至冷抗压强度大约为30kg，落差强度为150、并且取得较好的耐磨性能。

Amplified fluorescence of Mg^2+ selective red-light emitting carbon dot in water and direct evaluation of creatine kinase activity

Carbon quantum dot/carbon dot(CD)exhibiting sustained photoluminescence at longer wavelengths in aqueous solution is difficult to prepare,but has enormous potential in biomedical applications.For the first time,we report the magnesium(II)selective fluorescence enhancement of a red-light emitting anthrarufin and boric acid-derived CD in aqueous solution for direct evaluation of creatine kinase(CK)enzyme activity.The CD displayed visually detectable,intense red fluorescence only in the presence of magnesium ion(Mg^2+)at physiological pH value when irradiated with an ultraviolet(UV)source.Concurrently,a significant increase in steady-state fluorescence intensity and fluorescence lifetime was documented.A time-dependent density functional theory(TD-DFT)analysis displayed a bathochromic shift in UV–visible(vis)absorption,and increased oscillator strength of transition resulting from the selective chelation of Mg^2+withβ-hydroxy keto functionality on the surface of the CD.The CD–Mg^2+assembly was subsequently used to conceptualize the detection of CK directly through the exploration of the differential binding affinity of Mg2+with adenosine triphosphate(ATP),adenosine diphophate(ADP),and CD that is otherwise not possible with commercially available kits as of today.Thus,the report delineated here usher grandeur potential of CD for biological explorations related to Mg2+or ATP sensing and monitoring of Mg^2+-dependent enzymatic activity through a clear understanding of the chemistry.

Performance Assessment of Partially Pre-fused Synthetic Flux in Basic Oxygen Steel Making

Lump lime as the most common flux and iron ore as a coolant are used in basic oxygen steel making. However, high melting point, poor dissolution property, fines generation tendency and hygroscopic nature of lump lime often create problems in operation. As the combination of both iron oxide （Fe2O3） and CaO shows eutectic at 1 230 ℃, a combined mass of iron oxide and lime melts at lower temperature and dissolves faster in a molten bath. A partially pre-fused synthetic flux （PSF） was prepared through an innovative way in combination of iron oxide fines viz. Linz Donawitz converter sludge and blast furnace flue dust and lime fines by micro-pelletization of the mix followed by coke breeze free sintering. The developed PSF shows good cold handling strength, low melting point （1 180 ℃）, good thermal shock resistance, etc. As a low melting synthetic flux, its performance was assessed through dissolution/melting study in hot metal bath and refining of hot metal in a simulated bottom blown converter using （i） PSF, （ii） only lump lime and （iii） lump lime with iron ore when keeping other conditions identical. Very fast dissolution （27 80 s for 1-3 g lumps）, enhanced removal of C and P （11-12 min）, controlled slag foaming, and reduced oxygen consumption was obtained for using PSF.