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MnO_2是干电池的去极化剂和电子元件的磁性材料。本工作试图用简单的TG-DTA方法,辅以X衍射分析,研究由MnCO_3制备化学MnO_2的条件和判别MnO_2产品优劣的方法。 MnCO_3热分解成MnO_2的重要条件有二,缓慢升温并维持温度在300～350℃;使物料充分接触空气或氧气,保证氧化完全。利用TG—DTA谱图可以区分MnO2的晶型,β型无脱水峰;γ型400～600℃失重近于7％;α型和δ型290℃氧锰比为1.80左右,但后者有大而重叠的双脱水峰。优良的MnO_2在热分析曲线上的特征为:110℃前失重1～2％;160～450℃失重约3％;520～550℃的吸热峰大,失重率约为7％;160℃的氧锰比约2.0;MnO_2含量大于90％。
MnO 2 is a depolarizer for dry batteries and a magnetic material for electronic components. This work attempts to use simple TG-DTA method, supplemented by X-ray diffraction analysis of MnCO_3 preparation of chemical MnO_2 conditions and to determine the pros and cons of MnO_2 products. MnCO_3 thermal decomposition of MnO_2 important conditions are two, slowly warming and maintaining the temperature at 300 ~ 350 ℃; make the material fully exposed to air or oxygen, to ensure complete oxidation. The TG-DTA spectra can be used to distinguish the crystalline form of MnO2 from the non-dehydrated form of β. The weight loss of γ-type at 400-600 ℃ is almost 7%, while that of α-type and δ-type is about 1.80 at 290 ℃, While overlapping double dehydration peaks. The characteristics of the excellent MnO 2 on the thermal analysis curve are as follows: 1 to 2% weight loss before 110 ° C, 3% weight loss from 160 to 450 ° C, large endothermic peak from 520 to 550 ° C, and a weight loss rate of about 7% Oxygen to Manganese ratio of about 2.0; MnO 2 content greater than 90%.