| 摘要 |
PROBLEM TO BE SOLVED: To obtain a cement additive capable of shortening the dehydration time in the hydro-extraction step for a dehydration press in slate production process so as to improve slate productivity. SOLUTION: This cement additive consists of a reaction product which is obtained by addition reaction of a 2-8C alkylene oxide at >=5 mol per mol of a mixture of natural oil-and-fat and an 8-22C fatty acid (salt) in the molar ratio of (1:3) to (1:0.01); wherein the molar ratio: ethylene oxide/the 3-8C alkylene oxide is (1:40) to (2:1). |
