General-purpose silicate cement will stop using steel slag as a blended materials
On 27th November 2023, GB175-2023 “General Silicate Cement” was officially released, which will replace the 2007 edition and be implemented from 1st June 2024.
The 2007 edition is mandatory for the provisions, only the chemical composition, setting time, stability, strength and judgement rules of cement are mandatory for the provisions, and other provisions are recommended for adoption.
The 2023 edition stipulates that the main blended materials include granulated blast furnace slag/slag powder, fly ash, limestone and volcanic ash blended materials, and steel slag, which has been used for many years, is not included in the list. Due to the mandatory requirements of its full text, steel slag will not be able to be used as a blended material in the production of general-purpose silicate cement.
Steel slag is one of the major solid wastes generated by the iron and steel industry. Usually the amount of steel slag generated accounts for 10%-15% of crude steel production, measured by China’s crude steel output of 1.018 billion tonnes in 2022, the amount of steel slag generated is more than 100 million tonnes. The steel slag that achieves resourceful comprehensive utilisation is mainly used in the form of steel slag aggregate and powder for cement production, road construction, concrete making and in-plant recycling. According to preliminary estimates, the amount of steel slag used for general-purpose silicate cement is the largest, accounting for nearly 50% at the high point, about 50 million tonnes, the vast majority of which is used as a cement mixing material, and only a small amount (about 5%) is used as an iron corrective material for cement raw material batching.
Steel slag (powder) can be applied in concrete works (or asphalt concrete, construction mortar) instead of aggregate. Specifically, you can refer to the “Steel Slag Application Technical Specification” GB/T32546, “Mineral Admixture Application Technical Specification” GB / T 51003-2014 and other standards.
The application of steel slag in carbon sequestration, artificial reefs, 3D printing and other emerging fields is also being actively promoted, but the dosage is much lower than the cement industry. After the implementation of the 2023 edition, steel slag formerly used as cement mixing material needs to seek new areas and ways of utilisation.
