藉超重力碳酸化技術利用精煉鋼渣和含鈣廢水以制取水泥取代料

Abstract

本研究重點在於整合超重力技術與電去離子技術用以同時應對二氧化碳減量,硬水軟化與鹼性廢棄物處置再利用。本研究目的包括：(1)探究不同水樣對於精煉鋼渣中鈣離子浸出狀況之差異；（2）研究不同操作條件對於碳酸化反應之影響；（3）驗證碳酸化後精煉鋼渣用作輔助性凝膠材料之可行性；（5）從環境、經濟和工程三個面向評估超重力技術之效能。 精煉鋼渣是鋼鐵工業中精煉工藝的一種副產品，其中的不穩定組分如游離氧化鈣限制了其作為建築材料的利用，同時來自電去離子水的濃縮水是電去離子過程中產生的高濃度鈣離子廢水，具有較少的再利用途徑，而高濃度的鈣離子濃縮水可用作很好的碳捕捉材料。電去離子過程鈣離子濃縮水在本次研究中首次引入精煉鋼渣碳儲存過程。在本研究中（1）精煉鋼渣的浸出過程在 15 分鐘內完成，其中鈣離子動力學符合一級質量平衡模型。（2）反應時間，液固比，反應器轉速對碳酸化作用影響較大。表面覆蓋模型很好地表示了碳酸化動力學。最大可實現的碳水化合物轉化率為 69.8％。在碳酸化過程中鈣濃度隨著隨時間的增長而下降。（3）通過添加精煉鋼渣可以增強水泥的強度。具有 15％以下碳酸化後或 10％一下碳酸化精煉鋼渣取代相較純伯特蘭水泥具有更好的抗壓強度。

This research focuses on the integration of the High-gravity Carbonation Process and electrodeionization technology to simultaneously reduce carbon dioxide emissions, hard water softening, and alkaline waste disposal. The purposes of this study include: (1) Explore the leaching of calcium ions in refining slag with different water samples (2) Study the effects of different operating conditions on carbonation; (3) Verify the feasibility of replacing fresh and carbonated refining slag as supplementary cementitious materials; (5) Evaluate the whole process from environmental, economic and engineering aspects. Refining slag is a by-product of the refining process in the steel industry. Unstable components such as free calcium oxide limit its use as building materials, while concentrate from electrodeionization has a high concentration of calcium. Both raw materials can be used to capture carbon dioxide. In this study, it was found that (1) the leaching process of the refining slag was completed in 15 minutes. (2) Reaction time, liquid-solid ratio and reactor rotation speed have a great influence on carbonation，and the surface coverage model represents the kinetics of carbonation well. In addition, the maximum achievable carbohydrate conversion rate was 69.8%. (3) Compressive strength can be enhanced by adding both fresh and carbonated refining slag. Cement cubes under 15% carbonated refining steel slag under 10% fresh refining slag had better compressive strength than pure Portland cement.