以鹼活化技術資源化電弧爐煉鋼還原碴之研究

The use of alkali-activated electric-arc furnace reductive slag as binding material for concrete

郭硯華(Yan-hua Guo)

指導教授 ： 黃偉慶

國立中央大學/工學院/土木工程學系/碩士(2007年)

摘要

還原碴為電弧爐煉鋼爐碴生產過程中的副產品，並且產量龐大，屬於無機事業廢棄物，經適當處理後能發揮類似卜特蘭水泥的膠結功能，取代部份的水泥材料，達到資源化再利用的目的。
本研究利用鹼活化處理技術提升還原碴的活性，所使用之鹼活化劑為矽酸鈉及氫氧化鈉之組合，利用高pH值的特性激發還原碴膠結的能力，達抗壓強度的發展，做為混凝土製品中的膠結材料用。
還原碴的品質受煉鋼製程影響，本文針對不同採樣批次還原碴建立其膠結品質之強度檢測，評估各批還原碴是否適合於直接進行鹼活化之處理；未達標準者則利用添加20 %~30 %爐石之方式強化其活化成效。研究成果得知經鹼活化處理之還原碴，可符合卜特蘭Ι型水泥抗壓強度標準。此外，利用添加脫硫石膏於還原碴試體，可減少鹼活化還原碴試體之乾縮量。同時為掌握還原碴膠結料與細粒料之關係，進一步製作鹼活化還原碴高壓混凝土地磚，實驗得知7天抗壓強度可達國內高壓混凝土地磚之A級磚標準，證實鹼活化還原碴膠結料應用於混凝土製品之成效。

關鍵字

電弧爐還原碴 ； 鹼活化劑 ； 脫硫石膏

並列摘要

The reductive slag is a byproduct of steel-making industry using electric-arc furnace. In order to replace some cement materials, reductive slag can be processed to make its property similar to the binder of Portland cement. Meanwhile, this achieves the purpose of recycling.
This study used alkali activator to improve the activity of reductive slag so as to replace Portland cement as binder in concrete. By using sodium silicate and sodium hydroxide as alkali-activator, a high-pH environment is generated to excite the binding characteristics of reductive slag, and thus develops compressive strength of the mixes.
The binding quality of reductive slag is influenced by the processes of steel-making. The study has established the procedures in the evaluation of the binding quality of reductive slag. Using this procedure, it is possible to determine if each batch of reductive slag is suitable for alkali activation directly or not. The reductive slag not satisfying the requirement is recommended to be added a 20~30% blast furnace slag (BFS) for improvement in activation effects. Test results show that alkali-activated reductive slag satisfies compressive strength requirement for type I Portland cement. In addition, the addition of desulphurization gypsum to the reductive slag-BFS mixes will reduce the shrinkage of alkali-activated reductive slag.
Alkali-activated reductive slag as binding material is further extended to precast concrete products by applying it to the manufacture of concrete bricks. The compressive strength of mixes prepared using alkali-activated slag and fine aggregates was found to satisfy the domestic standard for Grade A concrete brick.

並列關鍵字

alkali-activator ； electric-arc furnace reductive slag ； flue gas desulfurization gypsum

參考文獻

ASTM C1038. (1995). “Standard Test Method for Expansion of Portland Cement Mortar Bars Stored in Water.” ASTM Designation.

ASTM C490.(2000) “Standard Practice for Use of Apparatus for the Determination of Length Change of Hardened Cement Paste, Mortar, and Concrete.” ASTM Designation.

Bakharev, T., Sanjayan, J. G., and Cheng, Y. B. (1999). “Effect of elevated temperature curing on properties of alkali-activated slag concrete.” Cement and Concrete Research, 29(10), 1619-1625.

Bakharev, T., Sanjayan, J. G., and Cheng, Y. B. (1999). “Alkali activation of Australian slag cement. ” Cement and Concrete Research, 29(1),113-120.

Bakharev, T., Sanjayan, J. G., and Cheng, Y. B. (2000). “Effect of admixtures on properties of alkali-activated slag concrete.” Cement and Concrete Research, 30(9), 1367-1374.