The effects of structure of retaining wall and dam on the flow condition of liquid steel in tundish are studied based on the physical model with geometric similarity ratio of 1∶4 established according to the similarity principle by taking the six-strand continuous casting tundish of bloom of Baotou Steel as the object of study. The results showed that the average retention time of liquid steel was increased by 5.51% and proportion of dead band was reduced by 20.73% by comparing the structures with and without retaining wall and dam. The flow condition of liquid steel in tundish could be effectively controlled, peak time and average retention time of each strand for tundish are increased as well as volume of dead band for the whole tundish is reduced so as to be beneficial to fully mixing liquid steel in tundish as well as aggregation and floating of inclusions.

In order to reduce the content of gangue minerals in iron concentrate, improve the grade of iron concentrate as well as reduce the consumptions of reagents and steam in the flotation process flow of iron, the magnetic separation with elutriation is added in the original process of Baoshan Mining Co. and the operation of a set of flotation system is reduced. The process of elutriation-flotation shows the good function of improving grade of iron as well as reducing contents of silicon, potassium and sodium. The grade of iron of iron concentrate reaches 67.07%, content of SiO₂ is 1.98%, content of K₂O and Na₂O is 0.172%, total operating productivity is 79.60% and recovery rate is 93.27%.

In the field of space launch, the filling system of liquid oxygen relates to whether launch mission is successful or not, so the measurement of flow velocity for liquid oxygen is crucial. The vortex flow meter is often used as its measuring instrument due to its advantages such as stable performances and wide ranges. It is found that the vortex street coefficients of vortex flow meter show different characteristics at low and high flow velocities through experimental simulation so that the precision of vortex flow meter is poor at low flow velocities. In order to explore the change characteristics of vortex street coefficient for vortex flow meter at low and high flow velocities, the simulation experiment of vortex street flow field with flow velocity of 1.0~10.5 m/s at inlet is carried out as well as the relational graph of vortex street frequency and inlet velocity is obtained. Moreover, the fitting curve of vortex street frequency and vortex street coefficient is obtained through fitting curve. Finally, it is found that the fluid flow velocity obtained by curve fitting is more accurate through calculating flow velocity with the obtained vortex street coefficient curve and average coefficient.

The iron ore samples are decomposed with the hydrochloric acid and hydrofluoric acid. After the perchloric acid smokes and silicon is eliminated, it is then extracted by butyl acetate solution of 1-phenyl-3-methyl-4- benzophthalide-5(PMBP). The interference elements of thorium are eliminated by the reextraction with hydrochloric acid, arsenazo III is as color developing agent and forms purple-red chelate with thorium ion as well as the thorium content in iron ore is determined with spectrophotometer. In the paper, the selection of acidity for extraction and reextraction, effects of such factors as acidity of chromogenic reaction, amount of color developing agent and color developing time on determination are discussed as well as experimental parameters are optimized. At the maximum absorption wavelength of 660 nm, the linearity range of thorium is determined to be 0~1.0 μg/mL, correlation coefficient is not less than 0.999 and detection limit is 0.000 44 μg/mL. This method is easy and simple to operate, molar absorption coefficient of the complex formed by arsenazo III and thorium is up to 0.8×10⁵ L/(mol·cm), which is with higher sensitivity. The adding standard recovery of thorium in the analysis results of samples is 96.8%~105.8%, so the method is with good precision and accuracy.

In this paper, the mechanical properties and metallographic structure of the joint with different welding technologies are compared and analyzed with the theoretical calculations of crack sensitivity index and preheating temperature as well as the methods of inclined Y-groove welding crack sensitivity test combining with operative weldability test of steel plate. Moreover, the JM-100 welding wire and 80%Ar+20%CO₂ argon-rich gas are determined to be adopted for welding the Q550D steel plate with thickness of 20 mm. The crack sensitivity index is 0.28, minimum preheating temperature is 13 ℃ and preheating treatment is not needed during welding. The welding heat input is controlled at 9.0~24.8 kJ/cm, temperature between weld passes is controlled below 200 ℃, mechanical properties of joint reach the best and there are no coarse and abnormal structures in weld seam and heat affected zone.

The metering data of energy is the basis for quantitative management of enterprise energy and realizing cost accounting as well as the important guarantee for establishing scientific and effective energy management system. The prediction model of priority and state for weighing apparatus is established as well as the optimal strategy of metering equipment is formulated through the technical researches of hot metal balance and early warning of equipment as well as analyzing the process flow related to hot metal balance between iron-making and steel-making processes. Moreover, the system based on visual data is designed for intelligent identification and judgment of relevant data of equipment, realizing automatic adjustment of metering device priority, early warning of anomaly, improving accuracy of metering data as well as eliminating metering objections scientifically and effectively so as to provide technical supports for hot metal balance between iron-making and steel-making processes, reduce the costs of per ton of steel, improve product quality and benefits as well as help the fine management of each factory and mine.

In the paper, it is introduced the organizational structure of remote centralized control system for air-compress station in Power Supply General Plant of Baotou Steel and applications of intelligent control system for power pipe network. A type of automatic control system suitable for remote control of air compressor is developed through exploring the processing properties of air compressor. Its applications in the performance control, anti-surge control and loop decoupling control of air compressor could make air compressor stabler and safer in remote operation.

In this paper, the effects of rare earth on the quality, metallurgical performances and mineral composition of sinter are systematically studied with sinter cup as well as the occurrence states of rare earth in different minerals of sinter are analyzed with scanning electron microscope and energy spectrum. The results showed that the sinter product ratio, utilization coefficient and drum strength tended to be increased first and then decreased, reducibility and low-temperature reduction degradation index of sinter tended to be improved first and then deteriorated, melting range was widened as well as the amount of formation for calcium ferrite in the mineral composition of sinter tended to be decreased with the proportion of rare earth increased. During the sintering process, the rare earth is into hematite, calcium ferrite and glass phase as well as it exists as columnar rare earth mineral in glass phase.

The effects of number of bottom gas supply component and bottom-blown gas intensity on mixing time of molten pool are studied through the water model test of bottom blowing system for 150 t converter in Steel-making Plant. The mixing time of 6 bottom gas supply components is the shortest with the same bottom-blown gas intensity; the higher the bottom-blown gas intensity, the shorter the mixing time with the same number of bottom gas supply component. The mode of bottom-blown gas supply in the processes of smelting different steel grades with 150 t converter is optimized combining with the results of water model test. As a result, the dephosphorization rate at smelting end-point could reach 92.3% and total iron content of slags at end-point of whole campaign could reach 17.3%, which could provide the technical guidance for improving the economic and technical norms of production.

In the external refining process, the elements of oxygen and sulfur are enriched in slag. In the process of smelting rare earth steel, the yield of rare earth is influenced. The reason is that the rare earth element Ce added with alloy reacts with the elements of O and S in slag to form compound so that a lot of rare earth elements remain in slag as well as just a small amount of them are into the link of pouring with liquid steel because of the active chemical property of rare earth elements. In the paper, the relation between refining slag amount and yield of rare earth element Ce is discussed through contrast test and analyzing the existence forms of rare earth element in refining slag. The results showed that the rare earth Ce in refining slag existed in the compound forms of oxides, sulfides and oxysulfides as well as the amount of refining slag affected the yield of rare earth Ce, which could provide the theoretical basis for improving it in industrial production process.