Natural Mg silicates with different structures and morphologies: Reaction with K to produce K2MgSiO4 catalyst for biodiesel production  

作　　者：Fabiane Carvalho Ballotin Mayra Nascimento Sara Silveira Vieira Alexandre Carvalho Bertoli Ottávio Carmignano Ana Paula de Carvalho Teixeira Rochel Montero Lago 

机构地区：[1]Departamento de Química,Universidade Federal de Minas Gerais,Belo Horizonte,Brasil [2]Doutorado Inovação/Mineradora Pedras Congonhas,Universidade Federal de Minas Gerais,31270-901 Belo Horizonte-MG,Brazil

出　　处：《International Journal of Minerals,Metallurgy and Materials》2020年第1期46-54,共9页矿物冶金与材料学报（英文版）

摘　　要：In this work, different magnesium silicate mineral samples based on antigorite, lizardite, chrysotile(which have the same general formula Mg3Si2O5(OH)4), and talc(Mg3Si4O10(OH)2) were reacted with KOH to prepare catalysts for biodiesel production. Simple impregnation with 20 wt% K and treatment at 700–900°C led to a solid-state reaction to mainly form the K2MgSiO4 phase in all samples. These results indicate that the K ion can diffuse into the different Mg silicate structures and textures, likely through intercalation in the interlayer space of the different mineral samples followed by dehydroxylation and K2MgSiO4 formation. All the materials showed catalytic activity for the transesterification of soybean oil(1:6 of oil : methanol molar ratio, 5 wt% of catalyst, 60°C). However, the best results were obtained for the antigorite and chrysotile precursors, which are discussed in terms of mineral structure and the more efficient formation of the active phase K2MgSiO4.In this work, different magnesium silicate mineral samples based on antigorite, lizardite, chrysotile（which have the same general formula Mg3Si2O5（OH）4）, and talc(Mg3Si4O10（OH）2) were reacted with KOH to prepare catalysts for biodiesel production. Simple impregnation with 20 wt% K and treatment at 700–900°C led to a solid-state reaction to mainly form the K2MgSiO4 phase in all samples. These results indicate that the K ion can diffuse into the different Mg silicate structures and textures, likely through intercalation in the interlayer space of the different mineral samples followed by dehydroxylation and K2MgSiO4 formation. All the materials showed catalytic activity for the transesterification of soybean oil（1:6 of oil : methanol molar ratio, 5 wt% of catalyst, 60°C）. However, the best results were obtained for the antigorite and chrysotile precursors, which are discussed in terms of mineral structure and the more efficient formation of the active phase K2MgSiO4.

关 键 词：silicate SERPENTINITE LIZARDITE ANTIGORITE TALC CHRYSOTILE biodiesel 

分 类 号：TE667[石油与天然气工程—油气加工工程] TQ426[化学工程]