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Preparation of high quality Microgranulate CrO 3 based on green process design
Author(s) -
Cui Wenwen,
Li Ping,
Chen Yongan,
Liu Chuang,
Zhang Hailin,
Wang Shulei,
Wang Hongyan,
Zheng Shili,
Zhang Yi
Publication year - 2017
Publication title -
the canadian journal of chemical engineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.404
H-Index - 67
eISSN - 1939-019X
pISSN - 0008-4034
DOI - 10.1002/cjce.22764
Subject(s) - quality (philosophy) , process (computing) , reliability engineering , computer science , process engineering , engineering , physics , operating system , quantum mechanics
Abstract A mild crystallization process was proposed to prepare chromium trioxide (CrO 3 ) by reaction between K 2 Cr 2 O 7 and HNO 3 aqueous solutions. Through ICP, XRPD, SEM, and EDS analysis, key factors and mechanisms that influenced the preparation of CrO 3 were studied. Large spherical particles of CrO 3 (d 50 ≥ 300 µm) with high purity (CrO 3 ≥ 0.99 g/g, K ≤ 2 mg/g) were prepared when the initial concentration of K 2 Cr 2 O 7 was kept at 80 g/100 mL HNO 3 , the acid feeding rate and the cooling rate were set at 1 mL · min −1 and 0.1 °C · min −1 , respectively, and the direct recovery of Cr 6+ was up to more than 95 %. Kinetic analysis indicated that low nucleation rate and high growth rate would favour the increase of CrO 3 particle size in this process. As a high‐valued byproduct, Cr(VI)‐free KNO 3 was further prepared with the designed crystallization steps. Additionally, green characteristics of the process were also discussed.