Advanced Materials Research Vols. 634-638

Abstract: The effects of ammonium adding temperature and coefficient on precipitation rate and product quality for a certain kind of vanadium-bearing solution are studied in this paper. On this basis, a further investigation is carried out to probe into the effects of Na, Si, and Al on the precipitation rate and product quality. It can be found in the experiments that the precipitation rate can reach to 99.328% or above with the optimal parameters listed as follows: ammonium adding temperature at 35~65°C, ammonium adding coefficient at 2, and Na, Si and Al content under 25 g/L, 1.5 g/L, and 0.1 g/L respectively. As a result, Na, Si, and Al content in ammonium polyvanadate(APV) is 0.058%, 0.053%, and 0.01% respectively.

Abstract: Using ladle slag, ferrovanadium smelting slag as well as slagging materials as starting materials, the converter slags with SiO₂ contents of 11.3% to 2.6%, Al₂O₃ contents of 3.3% to 19.1% were prepared and some cylinder-shaped MgO-C samples were processed to fulfill slag sticking tests conducted at 1600°C in atmosphere furnace. The research results show that the amount of slag adhesion decreases with a reduction of SiO₂ content and an increase of Al₂O₃ content in slag, owing to larger viscosity and higher foam index of molten slag. To control the variations of SiO₂ and Al₂O₃ contents in converter slag is conducive to better slag splashing. Furthermore, the mechanism of SiO₂ and Al₂O3 contents of converter slag impacted on slag sticking to MgO-C brick has been further discussed.

Abstract: Taken caustic calcined dolomite based compound desulfurizer as the research object, influence of fluxing agent CaF₂, Al₂O₃, SiO₂ and heating agent on the melting temperature of the compound desulfurizer was mainly investigated during its directly reducing process. Fluxing agent SiO₂ and heating agent are the main influence factors, which influence melting temperature of the compound desulfurizer, the next are CaF₂ and Al₂O₃. The mean value of compound desulfurizer melting temperature is respectively 1190.3°C and 1199_{Subscript text}.1°C when the addition amount of SiO₂ and heating agent is respectively 8.33% and 33.55%. With the increase of CaF₂, the mean value of compound desulfurizer melting temperature decreases gradually, however, which increases first and then decreases with the increase of Al₂O₃.The conditions of the lowest melting temperature about the compound desulfurizer is A₄, B₁, C₁, D₂, namely 9% CaF₂ + 0% Al₂O₃ + 8.33% SiO₂ + 33.55% heating agent.

Abstract: In this paper, we presented a prediction model of oxygen consumption of blast furnace (BF) based on least squares support vector machine (LSSVM) with the production data of an iron and steel factory. This method utilizes data pre-processing and parameters optimization to improve the fitting precision and operation speed of the model. By comparing the prediction results using different models with actual production data, we found out that the modified regression model of LSSVM is more suitable to predict the trend of oxygen consumption than others. The prediction accuracy is satisfactory and is helpful for oxygen system dispatch and production practice.

Abstract: The balling properties of pyrite cinder (PyC) with high content of copper are researched in this paper. The results indicate that grinding process is an effective way to improve the quality of green balls. Through the measuring of drop strength compressive strength and cracking temperature on pyrite cinder balls, it is found that the best bailing properties of PyC can be obtained under the recommended parameters (the content of grain size of PyC below 75 μm accounts to 95.75% and bentonite dosage is a mass ratio of 2%) and green balls with 5.4 frequency•(0.5m)-1 of drop strength, 15.8 N•each-1 of compressive strength and cracking temperature of about 700 °C are obtained, which can meet the requirements of metallurgical technology.

Abstract: Through chemical composition analysis of different grades casting intermixing slab with 0.40% carbon difference, a general law of molten steel mutual mixing has been drawn out. It reveals that different grades casting has a little effect on the tail-slab of former heat, but has a sever effect on the head slab of later heat.

Abstract: Due to the fact that it contains several kinds of toxic substances, stainless steel plant dust is regarded as a toxic solid waste. In this paper, XPS technique was employed to determine the elemental depth profiles on the surface of dust, especially Cr, in order to provide useful information on Cr(VI) formation mechanisms as well as the distribution of other element on the surface of stainless steel plant dust. The results showed that without sputtering with Ar ion beam, both Cr(VI) and Cr(III) exist on the surface of the dust. Cr(VI) mainly exists on the surface of the dust in the form of CrO₃. When the sputtering time is from 0s to 80s, the substances exist on the surface of EAF dust are Cr₂O₃ and CrO₃, and at the rest of the sputtering time, Cr₂O₃ is the only chromium-bearing substance existing on the surface of dust. When the sputtering time is from 0s to 80s, the substances exist on the surface of AOD dust are the same as the EAF dust. But at the rest of the sputtering time, Cr₂O₃ or FeCr₂O₄ are the chromium-bearing species.

Abstract: To assess some technologies which are more appropriate for the development of the iron and steel industry in China, a model was developed based on the Long range Energy Alternatives Planning System (LEAP) to assess the energy saving and CO2 reduction potentials from 2010 to 2040. The results show that the top three saving energy potentials is non-blast furnace iron-making accounted for 6.85%, device enlargement for 5.85%, advanced blast furnace for 4.84%, and also show that the top three CO2 reduction potentials is device enlargement accounted for 11.7%, non-blast furnace iron-making for 6.21%, advanced coke and blast furnace 5.52%. In the Mitigation scenario, it can reduce 28% of the initial energy demand and 35.2% of CO2 emissions. It can provide a method and data for search energy saving and CO2 reduction potentials in iron and steel industry by LEAP model.

Abstract: The experiments of smelting high nitrogen nickel-free stainless steel were carried out in the high temperature and high pressure reaction kettle. The nitrogen content was more than 1.36% by using the method of high pressure and bottom blowing nitrogen. With controlling high pressure nitrogen atmosphere and bottom blowing nitrogen, internal react were investigated by single factor experiment. Experimental results shown that there is saturated solubility, while smelting 18Mn18CrN steel with high pressure and bottom blowing nitrogen. Thermodynamic calculation model nitrogen solubility under the condition of high pressure was established, and the influence of nitrogen partial pressure on saturated solubility was researched.

Abstract: The entire life of a Blast furnace operator is spent to achieve the following aims: • To increase the productivity of Blast Furnace as high as possible. • To decrease the coke rate as low as possible to produce unit ton of hot metal. • To produce the hot metal of superior SG quality with particular reference to Sulphur & Silicon. • To keep the production cost as low as possible. The process indices of Mini Blast Furnace are similar to that of a conventional blast furnace. But, conventional blast furnace is capital intensive, solely dependent on good quality metallurgical coke, the gestation period is longer, and requires elaborate burden preparation. There is huge gap between demand and supply of steel in India. Also, India is dreaming to become developed nation by 2020. In such situations, the role of Mini Blast Furnace becomes very important. The slag chemistry is an important parameter to improve the process indices of MBF. The slag chemistry includes its chemical composition, liquidus temperature, fluidity, Sulphide capacity etc, which has an important bearing on the smooth & efficient operation of the MBF. The main important constituent of SG grade pig iron, particularly, Sulphur & silicon content should be 0.040% maximum and 1.20% to 2.20% maximum respectively. The chemical compositions of SG Grade Pig Iron is C- 3.80-4.20%, Mn – 0.35- 0.80%, Si – 1.20- 2.20%, S - 0.040% maximum and P – 0.15% maximum. The role of slag to produce such a low sulphur & low silicon in Mini Blast Furnace is very important. Therefore, to control Sulphur and silicon in SG Grade Pig Iron in Mini Blast Furnace, the optimisation of Slag Chemistry is an essential step.