In the paper, the theoretical inter-hole delay time and theoretical delay time between rows for such three types of lithology as iron ore, dolomite and slate in firing network are calculated by averaging as well as reasonable parameters are formulated to organize and launch bursting test through analyzing domestic and foreign rock breaking theory of millisecond blasting. The study showed that the reasonable inter-hole delay time of dolomite was 32 ms and that with blast block≤800 mm accounted for 98.17%; reasonable inter-hole delay time of slate was 40 ms and that with blast block≤800 mm accounted for 91.11%; reasonable inter-hole delay time of iron ore was 28 ms and that with blast block≤600 mm accounted for 82.16%. The proportions of qualified block corresponding to reasonable delay time of each lithology are increased.

In this paper, it is introduced the development process and achievements of beneficiation technology study of baiyuneboite. The study and application situations of beneficiation technology of baiyuneboite are introduced from such three stages as focusing on iron, paying equal attention to iron and rare earth as well as comprehensive utilization of resources. Moreover, it is summarized the methods for improving grade and recovery rate of iron concentrate, current situations of beneficiation of rare earth oxide, achievements of beneficiation of fluorite as well as breakthrough of beneficiation technology of niobium mineral.

In this paper, the research is carried out from such aspects as chemical composition, size composition, basic sintering characteristics and process parameters adjustment after production applications of Mongolian powder ore. The research results showed that the air permeability of sinter bed became worse, utilization coefficient was decreased by 0.001 t/ (m²·h), solid fuel consumption was increased by 0.83 kg/t, drum strength was decreased by 0.63 percentage point, average particle size was decreased by 0.05 mm, proportion of particle size of 5~10 mm in finished sinter was decreased by 0.12 percentage point and direct material cost was decreased by CNY 8.15 Yuan/ t when 7% Mongolian powder ore was used to replace the same proportion of Mac powder ore. The sintering process could maintain stable state by increasing moisture of mixture by 0.1 percentage point and fuel proportion by 0.2 percentage point.

In order to explore the effects of adding Indian powder ore on the production efficiency and quality of sinter, the experimental studies on basic sintering characteristics and sinter pot of Indian powder ore are carried out respectively. In the experiment, the current iron charge configuration of 2^# Sintering Workshop of Iron-making Plant is taken as the datum point as well as the Mongolian powder ore and high-silicon Brazilian coarse powder ore are replaced by Indian powder ore respectively. The performances of Indian powder ore are comprehensively evaluated from such aspects as the chemical composition, size composition and quality index of sinter, which provide the basis for determining appropriate adding proportion.

In the energy consumption of sintering process, solid fuel (powdered coke and anthracite) consumption accounts for 70%~80%, so it is the key to reduce solid fuel consumption for reducing energy consumption of sintering process. In the paper, it is introduced the air leakage rate of sintering machine is decreased to 35% and effective height of sinter bed is increased to 780 mm through such measures as equipment transformation, optimizing technological operations and strengthening production management combining with the existing conditions of raw materials and fuels aiming at the problem of higher solid fuel consumption for 265 m² sintering machine of Baotou Steel; proportion of size fraction of outsourced powdered coke <1 mm for sintering is decreased from 41.02% to 22.72% through revising the purchase standard of outsourced fuels for sintering so that size composition of fuel for sintering is improved. The solid fuel consumption for 265 m² sintering machine of Baotou Steel was reduced to 50.75 kg/t in 2023 through the above measures, which was 1.70 kg/t lower than that in 2021.

In the paper, the blast furnace smelting with large proportion of pellets is summarized as well as the effects of such processes as pelletizing, sintering and blast furnace on energy conservation and emission reduction of steel productions are quantificationally analyzed combining with actual production situations. The results showed that the carbon emission, energy consumption and pollutant discharge amount per ton of steel could be reduced by increasing the proportion of pellets and reducing the proportion of sinter in blast furnace. The study could be as reference for energy conservation and carbon emission reduction in the iron and steel enterprises with blast furnace-converter production process.

Such parameters as the outlet temperatures of crystallizer and secondary cooling section and shell thickness of manufacturing 2 types of rectangular billet with cross-section dimensions of 280 mm×380 mm and 320 mm×415 mm are simulated through high temperature thermal simulation experiments and computer software as well as the production process parameters of manufacturing YQ450NQR1 weathering steel with the billets of 2 different cross sections are compared. The results showed that the low magnification quality of billet was related to amplitude of crystallizer, amount of secondary cooling water, number of strands for continuous casting machine and temperature of exiting secondary cooling section while entering tension leveler. With the decrease of amplitude of crystallizer, increase of number of strands for continuous casting machine and temperature of entering tension leveler, the quality of billet is improved. When the amplitude of crystallizer is ±2.5 mm and temperature of entering tension leveler is greater than 940 ℃ with the condition of weak cold secondary cooling water, the low magnification quality of billet with cross section of 280 mm×380 mm of peritectic weathering steel is better than that of billet with cross section of 320 mm×415 mm.

The hot rolled coil plate for pipeline steel is mainly used for manufacturing delivery welded pipe of petroleum and natural gas. In this paper, the development of hot rolled coil plate for L485M pipeline steel with heavy gauge and low costs is introduced. The design with diversified alloy systems of C-Mn-Cr-Mo or C-Mn-Cr-Mo-Ni as well as smelting of clean steel and thermo mechanical control process (TMCP) are adopted. The microstructure of developed L485M hot rolled coil plate is acicular ferrite+granular bainite and precipitate is homogeneous. The L485M hot rolled coil plate is with such characteristics as high strength and excellent low temperature toughness through such mechanisms as dislocation strengthening and precipitation strengthening. The experimental results showed that the L485M hot rolled coil plates with and without Ni element could meet the technical requirements as well as was with capacity of batch production, which is beneficial for enterprises to reduce costs and increase benefits.

As one of key materials in the new energy automobile industry, non-oriented silicon steel for driving motor of new energy automobile is with broad application prospects and huge market potential. In this paper, it is discussed the performance indexes of non-oriented silicon steel for driving motor of new energy automobile as well as briefly summarized current research status of non-oriented silicon steel on such aspects as rare earth modification, optimization of annealing process and practical applications of motor. The overall performances of non-oriented silicon steel for driving motor of new energy automobile could be significantly improved by adding rare earth elements into non-oriented silicon steel, continuously optimizing annealing treatment process and making targeted improvements combining with the requirements of practical applications of motor.

The test steels with different La contents are smelted in vacuum induction furnace under laboratory conditions. The morphology and size of inclusions are studied with X-ray diffractometer, field emission scanning electron microscopy, Bruker energy spectrometer, OTS software and electron probe micro-analyzer (EPMA). The results showed that the inclusions, AlN and Al₂O₃ are modified into La-O-S, La-O-S-Al and LaS as well as inclusion size was decreased from 4.37 μm to 2.92 μm by adding La into X100 pipeline steel. The refinement effect of La on austenite grain size is obvious. With the increase of La content, austenite grain size in test steel is increased from level 5 to level 8.5. After adding rare earth La, the main inclusions in steel are La-O-S and La-O-S-Al of about 2 μm in size with the pinning effect so that austenite grain size is reduced significantly.