漿狀尾礦取代部分水泥原料燒製環保水泥之評估

Study of Feasibility on Eco-Cement Using Washed and Dried Slurry to Substitute Cement Raw Material

林政勳(Cheng-Hsun Lin)

指導教授 ： 王韡蒨 ； 張高豪

中原大學/工學院/土木工程研究所/碩士(2017年)

https://doi.org/10.6840/cycu201700842

摘要

本研究發現水洗除氯漿狀尾礦取代部分水泥鐵礦原料燒製環保水泥具有可行性，其原因為漿狀尾礦內含有碳酸鐵及少量氧化矽均可視為燒製水泥的材料。
控制燒製環保水泥的方法，以水泥係數值：HM=2.10、SM=3.02及IM=1.42進行生料的設計，決定尾礦取代鐵渣比例後，計算石灰石、矽砂、黏土、鐵渣及尾礦所需含量並混合均勻。採用20噸力並持壓3分鐘方式製作直徑50 mm、高15 mm的試錠。燒製水泥的升溫程序為：以10 ℃/min升溫速度由室溫升至850℃。850℃時持溫30分鐘。再以6 ℃/min升溫速度由 850 ℃升溫至1210℃。再以 4 ℃/min由1210℃升溫至1450℃。再在1450℃時持溫30分鐘；降溫方式以自然降溫方式進行，並在高溫爐自然降溫到達500 ℃時才打開爐門，將裝試體的坩鍋快速取出，並立即關上爐門，讓試體在室溫空氣環境快速冷卻，而高溫爐再自然降溫至室溫。試錠以直立式放置於坩鍋上，進行燒製作業。
以個別生料配料製作環保水泥，發現不會因添加過多尾礦導致嚴重的液相，讓熟料沾黏於坩鍋上，即使尾礦在高取代量條件，也能控制水泥係數符合目標值；凝結時間、比重試驗跟尾礦取代鐵渣之多寡無明顯關係，且符合CNS 61「卜特蘭水泥」的規定，另可以f-CaO之含量作為水泥品管控制的標準。
以個別生料配料燒製環保水泥進行性質試驗分析，發現環保水泥的水泥漿體抗壓試驗，水灰比控制0.35時，7及28天齡期的抗壓強度均表現良好；水灰比控制0.485時，尾礦取代鐵渣的用量達30 %時，7及28天齡期的抗壓強度仍可符合CNS 61「卜特蘭水泥」之規定；添加尾礦的環保水泥乾燥收縮量優於對照組； 以XRD分析，環保水泥中主要水化產物為CH、C-S-H和AFm；另進行TGA試驗，發現環保水泥中皆有CH、C-S-H膠體和CC(CaCO3)存在，在第7天齡期時的CH含量大於對照組；再以29Si之NMR分析結果顯示，當齡期增加時，其Q0會逐漸轉移至Q1 及Q2 峰上，可以推斷水泥中C-S-H膠體不斷的成長，惟尾礦取代鐵渣量在50 %以上時，7天齡期的水化程度較對照組低，但是達28天齡期時的水化程度則無明顯差異；最後進行SEM微觀分析發現，環保水泥的水化產物無明顯差異。綜合上述結果，可以驗證出尾礦在取代鐵渣製成環保水泥之潛力，但依目前尾礦取代量需小於鐵渣總量的30 %，如果取代量超過30 %時，可以往製作特殊水泥之目標發展。

關鍵字

環保水泥 ； 水泥漿 ； 抗壓強度

並列摘要

The findings of this study show that it is feasible to manufacture eco-cement by using water washing dechlorinated pasty tailings to replace partial cement iron slag material. Because the pasty tailings contain ferrous carbonate and a little silicon oxide which can be used to manufacture cement.
Method to control sintering of eco-cement, the raw material is designed by cement factor as: Hydraulic modulus =2.10, Silica modulus =3.02 and Iron modulus =1.42, when the replaced proportion of iron slag is determined, the required contents of limestone, silica sand, clay, tailings and the rest of iron slag are calculated and mixed well. The sintering specimen (Φ50mm × 15mm) is made by hydraulic press with force of 20 tonnes for 3 minutes. The test ingot is placed on the crucible upright and burnt. The specineus are placed in a saggerfor sintering. The cement firing temperature rises from room temperature to 850℃ at heating rate of 10℃/min. The temperature is kept at 850℃ for 30 minutes, it rises from 850℃ to 1210℃ at heating rate of 6℃/min, and from 1210℃ to 1450℃ at heating rate of 4℃/min, the temperature is kept at 1450℃ for 30 minutes to complete the sintering. The cooling curve is not controlled externally. The furnace door is closed until it is cooled to 500℃. The sagger with the specimen is taken out quickly when it reaches 500℃. Then the door of the furnace is closed to protect itself. The specimen is cooled quickly in the ambient.
The eco-cement is made by specific raw material blending, it is found that the excessive addition of tailings will not lead to severe liquid phase to stick specimen with sagger during high temperature. Even the replaced iron slag is high, the cement factor can match the target value. The specific gravity test shows that there is no obvious relation between the setting time and the replacement of iron slag by tailings, theu are compliant with the CNS standard. But the autoclave expansion test showed it is out of the specification. The soundness test will be required in the future. The f-CaO content shall be the a measurement of eco-cement quality.
The analysis and property testing of eco-cement. It is found that in the eco-cement paste compression test, when the water-cement ratio is controlled at 0.35, the compressive strengths at the ages of 7 and 28 days are good. When the water-cement ratio is controlled at 0.485, and the replacement of iron ore by tailings is 30 %, the compressive strengths at the ages of 7 and 28 days still conform to CNS 61. The dry shrinkage of the eco-cement with tailings is better than control group. The XRD analysis shows that the main hydration products in the eco-cement are CH, C-S-H gel and AFm. The TGA result shows that the eco-cement contains CH, C-S-H gel colloid and CC(CaCO3). The CH content in eco-cement at the age of 7 days is higher than control group. The NMR analysis result of 29Si shows that the Q0 transfers to Q1 and Q2 peaks gradually with age, it can be inferred that the C-S-H gel in the cement grows continuously. When the replacement of iron ore by tailings is higher than 50 %, the degree of hydration at the age of 7 days is lower than control group, but there is no significant difference in the degree of hydration at the age of 28 days. The SEM observations show that there is no significant difference in the hydration products of eco-cement. To sum up the aforesaid results, the potential of tailings in replacing iron ore to make eco-cement is validated, but the tailings replacement shall be less than 30 % of total content of iron ore. If the replacement exceeds 30 %, it can develop towards the objective of manufacturing special cement.

並列關鍵字

Ceo-cement ； Cement Paste ； Compressive Strengths

參考文獻

7 林韋志，「改質人工粒料取代天然細粒料應用於高壓混凝土磚之研究」，中原大學土木工程研究所，碩士論文，2014。

46 林凱隆、林忠逸、王鯤生、林家宏，「磷酸鹽含量對廢棄污泥燒製環保水泥之水化特性影響.」，環境保護，第二十七卷，第二期，第204~217頁，2004。

3 陳鈾森，「水洗尾礦造粒後之粒料特性探討」，國立中央大學土木工程研究所，碩士論文，2007。

5 呂劭君，「人工粒料作為路基材料及CLSM對RC構件和金屬腐蝕之影響研究」，國立中央大學土木工程研究所，碩士論文，2011。

6 林柏凱，「改質粒料取代天然粒料對混凝土」，國立中央大學土木工程研究所，碩士論文，2014。