Production of slag-bonded construction blocks by carbonation

钢渣是炼钢过程中的主要副产品，通常用作道路建设的集料。由于矿渣的高钙含量，使用矿渣作为道路集料并不能证明其潜力的合理性。另一方面，波特兰水泥的生产是一个能源密集型和二氧化碳排放过程。如果钢渣能够被激发来取代硅酸盐水泥，它可以被用来制造建筑产品，这些产品将显著降低体现能量和过程排放。麦吉尔大学的研究表明，磨碎的钢渣一旦压实成建筑产品，就可以与二氧化碳反应产生强度。这种强度足以制造用于建筑应用的砌块或墙板。二氧化碳活化将钢渣中的水硬性和非水硬性硅酸钙转化为水化硅酸钙和碳酸钙的混合物，碳酸钙是一种特殊的胶凝基质，可提高强度和耐久性。在建筑产品中使用钢渣作为主要粘结剂将消除波特兰水泥的使用，减少二氧化碳排放，利用工业废物，隔离二氧化碳，并消耗零原始材料。矿渣胶结产品是碳负性的，其性能可与商用水泥基产品相媲美。在我们前期工作的基础上，这项拟议的研究将进行原型生产，以展示以具有竞争力的价格生产全尺寸矿渣粘结砌块。该项目将研究在密度和成本之间进行权衡的优化混合设计，研究使用纯度为95%或15%的低浓度气体作为烟气的可能性，利用烟气活化生产全尺寸建筑砌块，并对新砌块进行耐久性和认证测试。其目标是生产具有经济竞争力、技术可比性和环境效益的绿色砖。如果成功，该产品将是世界上第一个此类产品。

Steel slag is a major by-product from the steel-refining process and is commonly used as aggregate for road construction. Because of its high calcium content, the use of slag as road aggregate does not justify its potential. On the other hand, production of Portland cement is an energy-intensive and a CO2 emitting process. If steel slag can be activated to replace Portland cement, it can be used to make building products that will show significantly reduced embodied energy and process emission. The research at McGill University has demonstrated that ground steel slag, once compact formed into a building product, can react with carbon dioxide to produce strength. This strength can be sufficient to make blocks or wallboards for construction applications. Carbon dioxide activation converts both the hydraulic and non-hydraulic calcium silicates in steel slag into a hybrid of calcium silicate hydrates and calcium carbonates, a special cementing matrix known to increase strength and durability. The use of steel slag as a primary binder in building products will eliminate the use of Portland cement, reduce carbon dioxide emissions, utilize industry wastes, sequester carbon dioxide and consume zero virgin materials. The slag-bond products are carbon-negative and their performance are comparable to commercial cement-based products. Based on our preliminary work, this proposed research will carry out a prototype production to showcase that full-scale slag-bond blocks can be produced at a competitive price. The project will investigate the optimized mix design to trade off the density and the cost, examine the possible use of low concentration gas of 95% purity or of 15% purity as flue gas, produce full scale construction blocks using flue gas activation, and conduct durability and certification tests of the new blocks. The goal is to produce green blocks that are economically competitive, technically comparable and environmentally beneficial. If successful, the product will be the first of its kind in the world.