A few days ago, Hebei Xinda Iron and Steel Group Co., Ltd. declared the invention patent of "a converter slag smelting method and converter slag smelting line", which was successfully authorized by the State Intellectual Property Office. The approval of the patent is not only an important milestone for Xinda in the field of technological innovation, but also a strong witness of its continuous promotion of steel smelting technology upgrading and high-quality development of the industry.

Analysis of current situation

Slagging is an essential part in the process of steelmaking and ironmaking. The difference between steel and iron is that the impurities contained are different, and the removal of harmful elements is a major challenge in steel smelting. Hot metal and scrap steel often contain harmful elements such as sulfur and phosphorus, if it can not be effectively removed in smelting, it will seriously affect the performance of steel, so it needs to be discharged in the form of slag by "slag making".

The theory of low-cost clean steel is the economic and technological development trend of modern metallurgical industry, and reducing the sulfur and phosphorus content of HRB400E high-strength seismic reinforcement is the key to ensure that the cold-bending and extension test of high-strength seismic reinforcement is qualified. The optimization of basicity of pulverized sinter slag is the optimal cost economic route to control the harmful elements of sulfur and phosphorus in HRB400E steel. At the same time, the powdery fine particles accelerate the slag-making rate of the converter, which is a necessary way to realize high-quality and high-strength seismic reinforcement.

However, in the prior art, there is no case of adding pulverized sinter below 10mm to the feed port above the converter's mouth. Fine sinter powder will be pumped away by the flue gas flow, and the sinter powder < 10mm separated by the vibration screening of the blast furnace trough cannot participate in the blast furnace reduction smelting. It will affect the gas permeability of blast-furnace material column, and can not be added into the converter furnace to participate in slag-making according to the normal method of adding slag-making agent.

Research measures

In the face of many challenges in the slag process of steel smelting, the R&D team of Hebei Xinda Iron and Steel Group Co., Ltd. has conducted in-depth research and is committed to finding an innovative solution to optimize the converter slag process and improve steel quality and production efficiency.

A new method of slag-making in converter was developed. The high basicness sinter powder with particle size less than 10mm was pressed into powder cored scrap by scrap pressing device, and the slag was dumped after the converter was pulled out. According to the total iron consumption, the scrap cored scrap was put into the converter. Add hot metal into the converter, the temperature of hot metal into the furnace should be ≥1250℃, the amount of slag is not more than 0.5%, then shake the converter body, add the amount of white ash block is 1/3 of the total amount of slagging solvent, and finally the lower gun begins to blow at high gun position. In the process of bconverter blowing, parameters such as oxygen gun position and oxygen pressure also have an important impact on the slag making effect, and the R & D team has carefully optimized these parameters through experiments.

Through the above measures, the surface scrap steel of the pressing block can be rapidly melted within 3 minutes of blowing, and the powder sinter can fully react with the harmful impurities in the hot metal and form slag through the agitation of the oxygen flow of the oxygen gun during the floating process, which greatly improves the slag making effect and efficiency.

Invention achievement

"A slag-making smelting method and a slag-making smelting line of converter" revolves around the innovative process of skillfully applying high alkalinity sinter powder to converter slag-making. In terms of improving the slag-making rate, the fine particles of the patent greatly accelerate the slag-making rate of the converter by adding powdered high alkalinity sinter; In terms of removing harmful elements, the removal of harmful elements phosphorus is solved in advance by optimizing the slag-making path and alkalinity control, which improves the quality and performance of steel bars. The high basicity sinter powder is pressed into powder core scrap to participate in converter slagging, which realizes the effective utilization of blast furnace waste and reduces the slagging cost.

"There is a long way to go, I will search up and down." Innovation is the eternal driving force for the development of The Times and a key engine for social progress. In the long road of exploration and breakthrough, Xinda has successfully won a number of national invention patents with unremitting efforts and persistence, which is an affirmation of past efforts, but also the key to open the door to future innovation. With an open attitude, the Group will continue to increase investment in research and development, further optimize patented technology, explore more application scenarios, accelerate the transformation of patent achievements, let innovation achievements solve more industry problems, inject a steady stream of power for the development of the industry, and write an innovative chapter in a broader world!