What is the application of steel slag in building materials?

In the process of iron and steel smelting, a large amount of iron and steel waste residue will be produced. According to different sources, it can be divided into blast furnace slag and steel slag. Among them, 0.25-0.50t blast-furnace slag is produced for every 1t of iron, and 0.15-0.20t steel slag is produced for every 1t of steel. The recycling of traditional steel slag is mainly used as the base material for road construction, or the use of high content of CaO, Fe0 and a certain proportion of Mg0, MnO and other components in steel slag, the steel slag is made into a ball and returned to the steelmaking furnace as an effective flux, which can reduce ore consumption and energy consumption. However, in these uses, the use of steel slag is limited, and the added value is very low. In order to increase the utilization and added value of steel slag, a very effective way is to produce steel slag cement after ultrafine grinding as a mixture of cement, or to use as an active admixture of concrete to prepare high-performance concrete.

Steel slag contains active minerals such as tricalcium silicate, dicalcium silicate, iron, aluminum, and salt, which are similar to cement. A large number of comparative tests and practical applications show that the activity of high quality steel slag is similar to that of blast furnace slag when the specific surface area is 550 m2kg. This shows that steel slag powder has a good market prospect and is a useful supplement for active mixed materials.

1, the application of steel slag cement: steel slag slag cement (referred to as steel slag cement) is based on steel slag, granulated blast furnace slag as the main component, adding an appropriate amount of Portland cement clinker and gypsum, grinding to make hydraulic cementing material. Because steel slag cement is based on steel slag and granulated blast furnace slag as the main raw materials, the production of this product can save limestone gaps, save energy, reduce CO2 and soot pollution to the environment, so it can also be called “green cement”. The steel slag cement prepared by adding 10% steel slag powder into the cement clinker has higher flexural strength and compressive strength than ordinary cement. Steel slag cement not only has the same physical properties as ordinary Portland cement, but also has a series of characteristics such as high late strength, high folding strength, good permeability resistance, good wear resistance, micro-expansion, low heat of hydration, corrosion resistance and so on. Steel slag cement is mainly used in general industrial and migrant construction, underground engineering and waterproof engineering, large volume concrete engineering, and special projects that have certain requirements for anti-seepage, anti-sulfate erosion and wear resistance.

2, the use of steel slag powder as an admixture: experimental studies have shown that after adding steel slag powder or composite steel slag powder to concrete, the bending strength becomes higher, the wear resistance becomes better, and the working performance of newly mixed concrete can be improved. In particular, it can reduce the occurrence time of hydration heat peak and delay peak, and the effect is more obvious with the increase of dosage. In addition, the concrete made of steel slag micro-powder has the characteristics of micro-expansion, which can compensate for shrinkage and reduce the dry shrinkage of concrete in the later stage, and can be widely used as a high-performance cement concrete admixture, which can significantly improve the physical and chemical effects of concrete such as folding strength, wear resistance, hydration heat and dry shrinkage performance.

The application of steel slag powder in the construction industry makes it play a role in reducing CO2 pollution source emissions after replacing cement, and every 1t of steel slag used in cement products can reduce CO2 emissions by 0.815t. If it is fully utilized, it can reduce the emission of 240 million tCO2 per year, which makes a great contribution to the CO2 emission reduction. Therefore, the steel slag micro-powder technology is the concentrated embodiment of the comprehensive utilization technology of steel slag into productivity, and shows the comprehensive progress of the comprehensive utilization technology of steel slag. GKLM series steel slag vertical grinding stone steel slag powder technology is the key equipment produced by Guikuang. GKLM vertical mill production process integrates crushing, grinding drying, powder selection, with low power consumption, good sealing performance, small footprint, simple process and so on. The required fineness and particle size distribution can be obtained by adjusting the speed of the separator, the air flow of the mill fan and the grinding pressure. With the change of design methods and concepts and the increasing maturity of process technology, the investment of vertical mill system is greatly reduced. The application of this system will be more and more extensive because of its advantages in performance and power consumption.