Key Laboratory of Ministry of Education on Safe Mining of Deep Metal Mines, Northeastern University, Shenyang 110819, China.
Process Engineering & Applied Science, Dalhousie University, 1360 Barrington Street, Halifax, NS B3J 2X4, Canada.
J Hazard Mater. 2014 Jun 15;274:322-30. doi: 10.1016/j.jhazmat.2014.04.007. Epub 2014 Apr 18.
The inerting effect of nano-sized TiO2 powder on ignition sensitivity of nano and micro Ti powders was investigated with a Mike 3 apparatus. "A little is not good enough" is also suitable for micro Ti powders mixed with nano-sized solid inertants. MIE of the mixtures did not significantly increase until the TiO2 percentage exceeded 50%. Nano-sized TiO2 powders were ineffective as an inertant when mixed with nano Ti powders, especially at higher dust loadings. Even with 90% nano TiO2 powder, mixtures still showed high ignition sensitivity because the statistic energy was as low as 2.1 mJ. Layer fires induced by ignited but unburned metal particles may occur for micro Ti powders mixed with nano TiO2 powders following a low level dust explosion. Such layer fires could lead to a violent dust explosion after a second dispersion. Thus, additional attention is needed to prevent metallic layer fires even where electric spark potential is low. In the case of nano Ti powder, no layer fires were observed because of less flammable material involved in the mixtures investigated, and faster flame propagation in nanoparticle clouds.
采用 Mike 3 装置研究了纳米 TiO2 粉末对纳米和微 Ti 粉末点火敏感性的惰化效应。“微量不足”也适用于与纳米尺寸固体惰化剂混合的微 Ti 粉末。直到 TiO2 含量超过 50%，混合物的 MIE 才显著增加。纳米 TiO2 粉末与纳米 Ti 粉末混合时作为惰化剂效果不佳，尤其是在较高粉尘负荷下。即使添加 90%的纳米 TiO2 粉末，混合物仍然表现出很高的点火灵敏度，因为统计能量低至 2.1mJ。微 Ti 粉末与纳米 TiO2 粉末混合后，在低水平粉尘爆炸后，可能会发生由点燃但未燃烧的金属颗粒引起的层状火灾。在第二次分散后，这种层状火灾可能导致剧烈的粉尘爆炸。因此，即使在电潜在较低的情况下，也需要额外注意防止金属层状火灾。在纳米 Ti 粉末的情况下，由于混合物中涉及的可燃材料较少，并且纳米颗粒云中的火焰传播速度更快，因此没有观察到层状火灾。
