Occurrences and Mineralogical Properties of Fibrous Sepiolites from Henan and Hebei Province, China

Abstract

Sepiolite is one of a magnesium bearing clay minerals having fibrous morphology, and is used as industrial raw material as adsorbent, filler, and so on. Considerable amount of sepiolite have hitherto been imported from U.S.A., Spain, and Turkey. These sepiolites are well-crystallized a-sepiolite showing no visible fibrous morphology. Recently, macroscopically fibrous sepiolite came to import from China. However, in so far as our knowledge, its occurrence and mineralogical properties have not been reported yet.
In this paper, mode of occurrences and mineralogical properties of macroscopically fibrous sepiolite from four deposits in Henan and Hebei Province, China is reported. In these deposits, sepiolite has been formed as veins crossing dolomitic limestone and crystalline limestone of Precambrian Era developed near the deposits. The XRD study clearly indicates that these minerals are well crystallized a-sepiolite with a small amount of calcite. In some cases, talc and/or tremolite was found as a minor impurity. Mineralogical data such as TG-DTA curves, chemical composition, SEM and TEM, etc. are also presented. The mode of occurrence as well as mineralogical properties of the sepiolite confirm that the sepiolite under consideration is a mineralization product by hydrothermal solution charged with magnesium, silica, etc., moving along the channelways created by fissuring.