The secondary preheating current is an important quality index for welding rails with GAAS80 type welding machine. In the welding process, it is with normal distribution. Whether the capability of secondary preheating current in welding process meeting the technical standards is sufficient or not can be effectively determined by analyzing the secondary preheating current with process capability index method, which is of great significance to improving the production efficiency of welding machine and ensuring stable quality.

In the paper, it is affirmed the operation method of lowering charge level of blast furnace and sending gas is advanced as well as elaborated the formation mechanisms and preventive measures for detonation or blast of vapour in blast furnace to blow out smoothly so that the requirements of simple and convenient, fast, environment friendly and safe are achieved. As a result, over 75% gas in blowing out could be recycled, which is with certain economical benefits.

With the process of desulphurization of hot metal-basic oxygen furnace-LF refing-vacuum degassing (VD) /RH treatment-continuous casting (CC), the yield is not closely related to the grade of steel, fluctuation of sulfur and oxygen content after add the rare earth, but it is strongly related to the type of processes. The effects of rare earth on denaturation of inclusions in steel are different for different steel grades. However, after add rare earth, the size of inclusions in steel decreases and their distribution becomes more dispersive so that the fatigue and impact performances are improved. The welding performance of steel plate after add rare earth is improved by delaying the formation of upper bainite and inhibiting the growth of austenite grains during welding.

The correlation of refining slag and inclusions was investigated as well as the influences of chemical composition and w (CaO)/w (Al₂O₃) of refining slag on the size, morphology and category of inclusions in steel were analyzed aimed at the production technology of SPCC steel. The results showed that the distribution of inclusions in steel was better, proportion of large-grained inclusions was smaller and proportion of small-grained inclusions was greater when w (CaO)/w (Al₂O₃) of refining slag was 1.38~1.66.

The wide and heavy plate production line of Baotou Steel adopts the green and clean steel making, continuous casting, double-stand rolling and heat treatment processes. A kind of green and environment friendly high-strength wear-resistant steel plate with rare earth used for construction machinery is researched and developed. It is with high strength, hardness and excellent wear resistance, good low temperature toughness and welding performance as well as the idea of circular economy is through its whole cycle process of production and use.

The Bayan Obo West Mine is a large open pit iron mine. In the paper, it is introduced the measures taken and achievements of constructing green mine of Bayan Obo West Mine from such aspects as environmental protection of mine, comprehensive utilization of resources, energy conservation and emission reduction and construction of digital mine for mining, beneficiation, tailings discharging and ore pulp conveying of Bayan Obo West Mine by taking the construction as the example. Moreover, the existing shortcomings are discussed to provide the basis for the future construction and development of West Mine.

In the paper, the key control and smelting process in each procedure of steel making for wheel steel with rare earth are introduced. The stable control for the yield of rare earth in steel and pourability of casting machine is realized with different controls of steel making process. Such procedures as KR desulfurization process, end point of converter, steel tapping, LF and RH refining process and casting in steel making are strictly controlled combining with the characteristics of deoxidation and desulfurization for rare earth elements to increase the yield of rare earth elements in steel. As a result, the yield of rare earth elements is guaranteed to be stably controlled at 38%~40% so that the production control for wheel steel with rare earth in steel making is completed.

At present, due to such outstanding advantages as the large ratio of crushing and strong crush capacity, the new-type high-efficiency hydro-cone crusher has been widely used in crushing system of mines. Its degree of automation is high and system structure is more precise so that the requirements for operation and maintenance become more stringent. In view of the high failure rate of cone crusher seriously affecting the continuity and smoothness of production of ore dressing system as well as the equipment maintenance costs are increased, it is important to realize delicacy management of crusher and establish corresponding management measures for reducing equipment failure rate and improving crushing efficiency.

In this paper, the steel-making production technology of adding rare-earth ferroalloy with the process route of LD-LF-RH-CC was studied. The results showed that the oxygen content of rare earth steel produced with trial production process was significantly lower than that of conventional steel. When the content of S in molten steel of tundish is lower, the inclusions are mainly RE_2O2S-CaO, RE₂O₂S and RE₂O₂S-Al₂O₃ below 2.0 μm, which are submicron inclusions with rare earth. The nozzle clogging materials are mainly deoxidation products of rare earth and aluminate of rare earth in steel as well as the aggregation and adhesion of rare earth inclusions are the main causes of nodulation.

Shenmu coal is with low ash, sulfur and cost as well as it is rich in coal storage. The coal blending amount of Shenmu coal could reach 3%~5% by carrying out the coal blending for coking test with directly blending Shenmu coal and coal blending tests with different fineness, optimizing coal blending structure, reasonable coal blending as well as improving cohesiveness of briquette blend. The results showed that the ash and cost of coke could be reduced by blending Shenmu coal, which provided the technical support for Baotou Steel to expand the usable range of coal source as well as reducing costs and increasing benefits.