Open AccessPREPARATION OF CALCIUM SULFATE HEMIHYDRATE WHISKERS FROM COMPLEX JAROSITE WASTE
Author(s) -
Hui Tan,
Xiaoqian Ma,
Faqin Dong,
Yufeng Li,
Jinming Wang,
Feihua Yang
Publication year - 2021
Publication title -
materiali in tehnologije
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.27
H-Index - 25
eISSN - 1580-3414
pISSN - 1580-2949
DOI - 10.17222/mit.2020.251
Subject(s) - jarosite , whiskers , gypsum , materials science , ammonium , sulfate , raw material , nuclear chemistry , impurity , zinc , metallurgy , ammonia , inorganic chemistry , mineralogy , chemistry , composite material , organic chemistry
Complex jarosite waste was obtained from zinc metal hydrometallurgical process, which contained gypsum and ammonium jarosite (NH4Fe3(SO4)2(OH)6). The influence of impurity ions (Fe3+ and NH4+) on the calcium sulfate hemihydrate (HH) morphology was studied using pure gypsum as the raw material, respectively. HH crystals with a high aspect ratio were obtained without the impurity ions. The diameter increased and the aspect ratio of the HH decreased, while the addition of iron sulfate and ammonia sulfate increased. Ammonium iron (NH4+) can be removed by using calcium oxide to decompose the ammonium jarosite in the waste and then to wash the sediment with tap water. The sediment (calcified jarosite sediment) mainly contained CaSO4·2H2O and Fe(OH)3. The influence of cultivating time on HH crystals growth was researched by using the sediment as raw materials. The diameter of the whiskers increased, while the hydrothermal time increased. The whiskers were obtained, with high a aspect ratio (10–60), large diameter (1–4 µm) and smooth surface, after the sediment was treated at 140 °C for 6 h in pH = 5 solution.