Upgrading of Iron Powder Adhesive in the New Era

As a key area in the battle against carbon emissions, the steel industry accounts for about 11% of the country's total energy consumption. The sintering process not only contributes to the main burden of blast furnaces, but also becomes an important source of pollutant emissions. 

 1、 Statistics show that the energy consumption of this process accounts for 12% -17% of the entire process, especially with solid fuel consumption accounting for over 75%. The sintering flue gas emitted not only accounts for half of the total emissions in the steel industry, but also carries more than 30 types of harmful pollutants such as SO ₂ and NOx. It is worth noting that the carbon emission intensity of China's steel industry is significantly higher than the international level, and its total carbon emissions have exceeded 60% of global steel carbon emissions, which constitutes an important constraint on the implementation of the dual carbon strategy. In terms of metallurgical by-product management, the dilemma of recycling sintered ore is particularly prominent. As a secondary resource with a particle size of less than 5mm, the proportion of recycled ore in the sintering system reaches 35% -45%. This high proportion of recycled material not only increases the energy consumption of the process by 15% -20%, but also forms a vicious cycle of "increased amount of recycled ore - decreased strength of sintered ore - regenerated recycled ore", directly affecting the increase of blast furnace fuel ratio by 1.5% -3.0%. Breaking through this technological bottleneck urgently requires the construction of a more effective system for the utilization of returned mineral resources. 

 2、 Technological innovation path and implementation plan 1. Resource integration technology plan: By constructing a diversified iron containing raw material ratio system, the return ore and solid waste such as iron concentrate powder and steel slag micro powder are compounded in a ratio of 45% -60%: 25% -35%: 10% -15%, with a composite binder (added at a dosage of 1.2% -1.8%), and achieved a uniformity of over 97% through a three-level mixing system. During the molding stage, dense green balls with a diameter of 20-30mm are prepared using a pressure of 800-1200kN/cm ². After treatment in a two-stage drying kiln (180-220 ℃), the compressive strength of the finished balls can reach over 600N/ball, fully meeting the strength requirements of blast furnace burden. 2. Microscopic consolidation mechanism analysis: This technology breaks the random stacking structure of powder particles through high-pressure forming, promoting the filling of gaps between coarse particles with -0.074mm fine particles, forming a dense "skeleton filling" composite structure. During the thermal activation process, the adhesive produces nano scale cementitious substances, which construct a three-dimensional network bonding system through a dual action of chemical bonding and physical adsorption. The surface hydroxyl condensation reaction generated during the drying stage allows the pellets to form crystal bonding strength equivalent to traditional pellets fired at 800 ℃ at 200 ℃, achieving low-temperature consolidation. The key control parameters include: specific surface area of the raw material (≥ 1800cm ²/g), pH range of the binder (8-12), mixing time (8-12 minutes), and drying rate gradient (15-25 ℃/h). The application of this technology system can increase the comprehensive utilization rate of return ore to over 95%, reduce the energy consumption per ton of ball by 65% -70% compared to traditional processes, and increase the consumption rate of solid waste such as steel slag by over 40%. It provides a better solution for steel enterprises to build a green development model of "zero solid waste emissions, high-value resources, low-carbon and low-cost"