The occurrence state and change rules of stock for rare earth in high carbon medium manganese steel as well as effects of rare earth on sulfide inclusions, oxide inclusions, microstructure, hardening efficiency of static compression and impact wear property are systematically studied through metallographic observation, 30% static compression, impact wear test and theoretical analysis. The study results showed that the content of solid solution rare earth for high carbon medium manganese steel could not be increased by adding a large amount of rare earth and it remained below 0.003 5%. The hardening efficiency of 30% static compression at room temperature for high carbon medium manganese steel is improved by adding rare earth, which is increased from 63.25% without rare earth to 78.57% ~88.37% with rare earth. The impact wear resistance of high carbon medium manganese steel is improved. The relative wear resistance is increased by 1.010 0~1.893 0 times with impact load of 2 J and it is increased by 1.391 3~1.822 8 times with impact load of 5 J. The optimal amount of rare earth added into high carbon medium manganese steel is 0.20%~0.25% under the experimental conditions.

In this paper, YQ450NQR1 zed beam is taken as the research object and trace rare earth elements are added in smelting process to improve its corrosion resistance. The influences of trace rare earth elements on corrosion resistance of YQ450NQR1 zed beam are studied by phase detection, alternate immersion accelerated corrosion test and electrochemical analysis of rust layer. The study results showed that the grain could be refined, stable α-FeOOH could be promoted to be generated so that rust layer was more compact by adding trace rare earth elements into YQ450NQR1 zed beam. As a result, the self-corrosion potential of material is improved and transfer resistance of charge is increased so that the corrosion resistance of material is improved.

In the paper, it is proposed the method of detecting such problems as tearing, surface tears, edge damages and foreign matters of materials for travelling belt adopting 3D vision technology in such industries as mining and metallurgy, elaborated the technical principles and detection algorithms of detecting surface defects for travelling belt based on 3D vision technology as well as described the design and installation way of visual image acquisition device suitable for dusty working environment. The detection system of surface deterioration trend and tearing for travelling belt is suitable for such operation environments of transporting large-scale bulk material as steel metallurgy and ports. It has been in operations in steel enterprises for two years, during which the surface tears of travelling belt are detected timely and accurately so that further expansion of faults is avoided and good effects are achieved.

The endurance bending strength of gear for reducer is checked as well as it is deduced that it is seriously lower under the impact load of billet to work roll table so as to cause the problems of frequent gear tooth break and locating key cutting based on structure of reducer for work roll table of CCS rolling mill combining with causes of billet impacting work roll table and its impact load.Under the original working conditions, reasonable structure of reducer for work roll table is obtained by using the locating key with double keyways after quenching and tempering, increasing length and height of output shaft for reducer, changing size of base for reducer as well as increasing such parameters as maximum output torque and input power. After the optimization, endurance bending strength of tooth root and contact fatigue strength of tooth surface for reducer could meet the requirements of on-site working conditions.

The pure water generally prepared with industrial raw water by adopting the process of membrane treatment+mixed bed water treatment is used for boiler feedwater of coke dry quenching in coking industry. There is repeatability for membrane treatment process in advanced treatment of phenol cyanogen wastewater and preparation process of boiler feedwater, so demineralized water can be replaced by advanced treatment for contributing water to reduce the operating costs of enterprises. It is preliminarily determined to be with feasibility through studying the characters of water quality and water quantity of effluent from demineralized water system of boiler feedwater and reuse water of phenol cyanogen wastewater. The industrial test results showed that the indexes of effluent could satisfy the operating requirements of boiler for coke dry quenching, quantity of fresh water used was reduced by 90% and disposing costs of demineralized water was reduced by 15%~20% with the scheme, which could provide the technical support for “zero discharge” of phenol cyanogen wastewater.

In this paper, the digital twin model for production process of rare earth products is established based on digital twin technology and its visual representation in virtual space is realized. The full-process integration from data collection, transmission to model establishment and visualization is realized with the system through the design of layered architecture. In practical applications, the real-time collection of key equipment data for production line of rare earth oxide could be realized with the system as well as running status of equipment and production process could be visually displayed through the three-dimensional visualization technology. The implementation results showed that the monitoring efficiency in production process was significantly improved, production processes were optimized, production costs were reduced and product quality was improved by applying digital twin technology.

The rare earth in baiyuneboite is recovered with the process of concentration-flotation-concentration-filtration in Baoshan Mining Co.. During the concentration process of concentrate, about 4% of rare earth resources are run off from overflow of concentrate, their grade is 26.17% by detection and most of their particle sizes are 5~20 μm so that they are micro-fine particles. In this paper, the overflowed concentrate of large well of concentrate in Baoshan Mining Co. is with sampling analysis. The rare earth resources are recovered with various methods as flotation, desliming flotation, magnetic concentration and gravity concentration. Finally, the rare earth ore concentrate with grade of 50.72% and recovery rate of 30.82% is obtained with the gravity concentration method, which is with significant guiding function for comprehensive recovery of rare earth resources in Bayan Obo.

The scale generated on polyurethane sieve mesh caused by long-term use could be effectively removed with the acid leaching method so as to recover its screening efficiency. The efficient descaling could be realized by soaking polyurethane sieve mesh in 2% oxalic acid solution for 12 h so that the screening efficiency could be recovered to 62.33%; although the descaling efficiency of sieve mesh with hydrochloric acid is high, treatment costs of waste acid is high, so it is not recommended for long-term use; the screening efficiency of soaking sieve mesh in the mixed solution of 0.5% hydrochloric acid and 0.5% oxalic acid for 12 h is similar to that of sieve mesh after using 15 days, but the operations of preparing acid solution are complex, so it is not recommended for long-term use. The 2% oxalic acid solution is used to soak the sieve mesh after using 180 days for 12 h to remove its scale considering the impacts of waste acid after descaling on the environment.

In this paper, the process flow and problems in process of production and operation for desulfurization and denitrification system of flue gas of coke oven are introduced in detail. The operation of the system is stable, emission indexes of flue gas are acceptable, repair cycle of the system is extended so that repair frequency is reduced and hourly qualified rate per month of emission for flue gas of coke oven is guaranteed to be over 95% through taking such measures as adjusting the heating schedule of coke oven, grouting of coke oven, sealing desulfurization and denitrification system, reforming denitrification system, strengthening heat preservation of gas pipeline as well as reducing impurities in gas.

The ultrasonic flaw detection of fixed flash welding joints for 60 kg/m-U75V rail is carried out in a welded rail base. It is found that there is excessive alarm of flaw detection at the rail bottom corner at welding line. The joints with defects are analyzed through metallographic observation, detections with scanning electron microscope and energy dispersive spectrometer (EDS). The results showed that the lack of fusion and hole defect were observed at weld bond at rail bottom of welded joint at the position marked by rail detecting as well as there were gray spots and abnormal bulk inclusions at fracture of bending. Analysis suggested that the main causes of flaw detection alarm were the lack of fusion and hole defects caused by formulating improper welding process parameters as well as excessive inclusions in base material. The defects could be reduced by optimizing welding process and improving metallurgical quality of base material.