Production of slag-bonded construction blocks by carbonation

钢渣是炼钢过程的主要副产品，通常用作道路建设的骨料。由于其高钙含量，使用矿渣作为道路骨料并不能证明其潜力。另一方面，波特兰水泥的生产是能源密集型和CO2排放过程。如果钢渣可以被活化以取代波特兰水泥，它可以用于制造建筑产品，这将显示出显着降低的隐含能量和过程排放。麦吉尔大学的研究表明，磨细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。该强度可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硅酸钙水合物和碳酸钙的混合物，这是一种特殊的胶结基质，已知可提高强度和耐久性。在建筑产品中使用钢渣作为主要粘合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，封存二氧化碳，并消耗零原始材料。矿渣粘结剂产品是碳负的，其性能与商业水泥基产品相当。基于我们的前期工作，本研究将进行原型生产，以展示可以以具有竞争力的价格生产全尺寸的矿渣结合块。该项目将研究优化的混合设计，以平衡密度和成本，研究使用纯度为95%或15%的低浓度气体作为烟气的可能性，使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。目标是生产经济上具有竞争力、技术上具有可比性和环境效益的绿色砌块。如果成功，该产品将是世界上第一个。

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.