Sodium-modification of Ca-based bentonite via semidry process

Abstract

In order to improve the quality of Hunyuan inferior Ca-based bentonite (Ca-Bent), semidry process was used to modify Ca-Bent into superior Na-based bentonite (Na-Bent). The factors affecting sodium-modification were investigated. The optimized experimental parameters are obtained as follows: Na₂CO₃ dosage 4.0%, ageing time 25 d, briquetting pressure 25 MPa and briquetting moisture 20%. Under the optimization conditions, the modified Na-Bent has a colloid value of 73.6 mL/(3g), dilation of 38 mL/g and water absorption in 2 h (2HWA) of 465%, respectively. The balling results indicate that the modified Na-Bent pellets have higher drop strength and compression strength than the Ca-Bent pellets.

Keywords

Ca-Bent / Na-Bent / sodium-modification / semidry process / pellet binder

References

[1] QiuG.-z., JiangT., LiH.-x., WangD.-zuo.. Functions and molecular structure of organic binders for iron ore pelletization [J]. Colloids and Surfaces A, 2003, 224: 11-22

[2] QiuG.-z., JiangT., HuangZ.-c., ZhuD.-q., FanX.-hui.. Characterization of preparing cold bonded pellets for direct reduction using an organic binder [J]. ISIJ International, 2003, 43(1): 20-25

[3] YangY.-b., HuangG.-x., JiangT., HuangZ.-c., LuoY., HuangY.-lei.. Application of organic binder as substitutes for bentonite in pellet preparation [J]. Journal of Central South University: Science and Technology, 2007, 38(5): 850-856

[4] QiuG.-z., JiangT., FaK.-q., ZhuD.-q., WangD.-zuo.. Interfacial characterizations of iron ore concentrates affected by binders [J]. Powder Technology, 2004, 139(1): 1-6

[5] ZhangY.-x., TianF.-c., ZhangK.-c., ZhaoHeng.. Pelletizing test of adding various complex binders [J]. Sintering and Pelletizing, 2004, 29(5): 9-11

[6] KawatraS. K., RipkeS. J.. Developing and understanding the bentonite fiber bonding mechanism [J]. Minerals Engineering, 2001, 14(6): 647-659

[7] KawatraS. K., RipkeS. J.. Laboratory studies for improving green-ball strength in bentonite-bonded magnetite concentrate pellets [J]. International Journal of Mineral Processing, 2003, 72(1/4): 429-441

[8] KawatraS. K., RipkeS. J.. Effects of bentonite fiber formation in iron ore pelletization [J]. International Journal of Mineral Processing, 2002, 65(3/4): 141-149

[9] LiH.-x., WangD.-z., HuY.-h., QiuG.-z., JiangTao.. The mechanism of improving pellet strength by carboxyl methlated amylum [J]. Journal of Central South Technology University: Science and Technology, 2001, 32(4): 351-354

[10] LIU Peng-jun, ZHANG Yu-zhu, CAO Zhao-zhen, LI Zhen-guo, YIN Hai-sheng. Preparation of Na-bentonite from Ca-bentonite and its application in pellet [J]. Multipurpose Utilization of Mineral Resources, 2006(4): 3–6. (in Chinese)

[11] ZhouJ.-r., YiF.-c., HouLi.. Study status on solidum-modified method of Ca-bentonite [J]. China Mining Magazine, 2007, 16(3): 84-87

[12] YiF.-c., ChenT.-f., LiuS.-hai.. Technology and application of organic bentonite [J]. Chinese Mineral Industry, 1998, 7(1): 70-73

[13] ChenZ.-y., LiY.-l., ZhangZ.-y., JiangK.-ge.. Preparation and structural performance analysis of organic bentonite [J]. Non-metallic Mines, 2002, 25(5): 45-47

[14] LiB.-y., YangD.-f., WangY.-jie.. A study on the modified-property of bentonite [J]. Jilin Geology, 2005, 24(2): 44-49

[15] CAO Yao-hua, YANG Shao-wen, GAO Zhao-guo, LI Qi. Modification research of Ca-bentonite as drilling Na-bentonit [J]. Conservation and Utilization of Mineral Resources, 2007(1): 20–22. (in Chinese)

[16] JiangG.-l., ZhangP.-ping.Processing and application of bentonite [M], 2005, Beijing, Chemical Industry Press: 162

[17] LiQ.-lin.Studies on preparation mechanism and application of alkaline Ca-bent [D], 2007, Nanning, Guangxi University: 1-10

[18] YanJ.-h., LiJ.-m., HuiB.-ran.. Study on the technics of preparing high-efficient active white clay by the method of half-dry [J]. Journal of Changchun University of Science and Technology, 2003, 26(4): 37-39

[19] QinP.-cheng.. Productive practice of sodium-modification of Ca-bentonite [J]. China Non-Metallic Mining Industry Herald, 2003, 37(6): 28-30

[20] ÖnalM., SarikayaY.. Preparation and characterization of acid-activated bentonite powders [J]. Powder Technology, 2007, 172: 14-18