无机盐工业
主管:中海油天津化工研究设计院有限公司
主办:中海油天津化工研究设计院有限公司
   中海油炼油化工科学研究院(北京)有限公司
   中国化工学会无机酸碱盐专业委员会
ISSN 1006-4990 CN 12-1069/TQ

无机盐工业 ›› 2020, Vol. 52 ›› Issue (5): 22-26.doi: 10.11962/1006-4990.2019-0588

• 研究与开发 • 上一篇    下一篇

MgCO3·3H2O晶须的制备及其生长机制的研究

王彦霞,程文婷(),方莉,程芳琴   

  1. 山西大学资源与环境工程研究所,山西省煤炭废弃物高附加值利用协同中心,山西太原 030006
  • 收稿日期:2019-11-21 出版日期:2020-05-10 发布日期:2020-05-21
  • 通讯作者: 程文婷
  • 作者简介:王彦霞(1994— ),女,硕士研究生,研究方向为MgO晶须的可控制备。
  • 基金资助:
    国家自然科学基金(U1707603)

Study on preparation and growth mechanism of MgCO3·3H2O whiskers

Wang Yanxia,Cheng Wenting(),Fang Li,Cheng Fangqin   

  1. Institute of Resources and Environmental Engineering,Shanxi Collaborative Center of High Value-added Utilization of Coal-related Wastes,Shanxi University,Taiyuan 030006,China
  • Received:2019-11-21 Online:2020-05-10 Published:2020-05-21
  • Contact: Cheng Wenting

摘要:

以MgCl2·6H2O和NH4HCO3为原料,CH3COONa·3H2O为形貌控制剂,采用沉淀结晶法制备MgCO3·3H2O晶须,考察了不同添加量的CH3COONa·3H2O对晶须结晶过程和形貌的影响,并研究了晶须在该体系中的生长机制。结果表明:当体系中加入质量分数为0.23%的CH3COONa·3H2O时可以成功制备长径比约为30的棒状MgCO3·3H2O晶须,CH3COONa·3H2O的存在促进了MgCO3·3H2O晶须的形成。该体系中晶须的生长过程:首先形成无定形的4MgCO3·Mg(OH)2·4H2O,之后无定形4MgCO3·Mg(OH)2·4H2O逐渐转变为MgCO3·3H2O并生长成较大长径比的棒状MgCO3·3H2O晶须。这是因为CH3COONa·3H2O电离产生的Na +选择性吸附在MgCO3·3H2O晶体轴向的(101)晶面,抑制了该晶面生长,而径向晶面生长速率未受到影响,从而促使无定形MgCO3·3H2O生长成棒状晶须。

关键词: MgCO3·3H2O晶须, CH3COONa·3H2O, 沉淀结晶, 生长机制

Abstract:

MgCO3·3H2O whiskers was prepared with MgCl2·6H2O and NH4HCO3 as raw materials and as CH3COONa·3H2O morphology control agent by precipitation crystallization method.The effects of different amounts of CH3COONa·3H2O on the crystal and morphology of MgCO3·3H2O and the growth mechanism of whiskers in the system were investigated.The results showed that the rod-shaped MgCO3·3H2O whiskers with a length to diameter ratio of 30 can be successfully prepared when the amount of CH3COONa·3H2O added was 0.23%(mass fraction).CH3COONa·3H2O may be beneficial to the formation of whiskers,and the growth mechanism of which was proposed:firstly,amorphous 4MgCO3·Mg(OH)2·4H2O was formed,and then they gradually transformed into MgCO3·3H2O and grown into rod-shaped whiskers.The Na + produced by CH3COONa·3H2O were selectively adsorbed on the(101) crystal plane of the axial direction of MgCO3·3H2O crystal,which inhibited the growth of the crystal plane,and the radial growth was not significantly affected,which promoted amorphous MgCO3·3H2O grew into the rod whiskers.

Key words: MgCO3·3H2O whisker, CH3COONa·3H2O, precipitation crystallization, growth mechanism

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