Maceral minerals

The composition of any individual coal beneficiation feed particle ranges from a nearly uniform metamorphized plant component through an almost infinite mixture series with macerals-minerals to an opposite end member as a nearly uniform mineral component. The behavior of a beneficiation feed during processing is determined by... 

This approach to coal benefication is flexible and is applicable to a variety of coals because the nature of maceral-maceral and maceral-mineral interactions are similar for similar coals. The coal is modified both chemically and physically in a way which allows selected mineral components to be attacked. It is believed that improvements can be made which will be more effective in terms of degree and specificity for mineral matter removal, while potentially effecting a route to organic sulfur removal. 

Macerals. Coal parts derived from different plant parts, are referred to as macerals (13). The maceral names end in "-inite" as do the mineral forms of rocks. The most abundant (about 85%) maceral in U.S. coal is vitrinite, derived from the woody tissues of plants. Another maceral, called liptinite, is derived from the waxy parts of spores and poUen, or algal remains. The liptinite macerals fluoresce under blue light permitting a subdivision based on fluorescence. A third maceral, inertinite, is thought to be derived from oxidized material or fossilized charcoal remnants of early forest fires. 

Pieces of coal are mixtures of materials somewhat randomly distributed in differing amounts. The mineral matter can be readily distinguished from the organic, which is itself a mixture. Coal properties reflect the individual constituents and the relative proportions. By analogy to geologic formations, the macerals are the constituents that correspond to minerals that make up individual rocks. For coals, macerals, which tend to be consistent in their properties, represent particular classes of plant parts that have been transformed into coal (40). Most detailed chemical and physical studies of coal have been made on macerals or samples rich in a particular maceral, because maceral separation is time consuming. 

It is well known that during liquefaction there is always some amount of material which appears as insoluble, residual solids (65,71). These materials are composed of mixtures of coal-related minerals, unreacted (or partially reacted) macerals and a diverse range of solids that are formed during processing. Practical experience obtained in liquefaction pilot plant operations has frequently shown that these materials are not completely eluted out of reaction vessels. Thus, there is a net accumulation of solids within vessels and fluid transfer lines in the form of agglomerated masses and wall deposits. These materials are often referred to as reactor solids. It is important to understand the phenomena involved in reactor solids retention for several reasons. Firstly, they can be detrimental to the successful operation of a plant because extensive accumulation can lead to reduced conversion, enhanced abrasion rates, poor heat transfer and, in severe cases, reactor plugging. Secondly, some retention of minerals, especially pyrrhotites, may be desirable because of their potential catalytic activity. 

Perhaps the most important components of reactor solids are those that are generated during processing rather than those that are derived from inert minerals (quartz, clays) and macerals (fu-sinites, etc.) in the feed coal (74). The retention of these formed materials is more difficult to predict from the characteristics of the feed and, hence, control in liquefaction processes. 

Sodium in Plants and Animals. By macerating certain plants in warm water acidified with different mineral acids, G.-F. Rouelle (1703-1770) prepared and identified the neutral sodium salts of the corresponding acids and thus demonstrated the presence of the mineral alkali (sodium carbonate) in these plants. He believed that the sodium carbonate was not merely absorbed from the soil but that it was a true product of vegetation (11). 

Complete removal of inert macerals and minerals from the starting coal and complete conversion of reactive macerals at the expense of excess production of hydrocarbon gases. In this situation, the recycled bottoms consist of only catalyst and heavy coal liquid products. Reactor designs should attempt to avoid catalyst deactivation, providing immediate reuse of the catalyst. 

Chemical separation of the catalyst from the bottom products. Some coals, such as Australian brown coal, consist principally of reactive macerals and contain organically bound calcium and sodium, which almost exclusively produce carbonate and chloride minerals during liquefaction. The catalyst can be separated by extracting these minerals, which exist on the catalyst surface or as precipitates in the bottoms product. 

Vitrinoids. Before describing the macerals in thin sections, it should be pointed out that the sections were prepared maintaining the uniform thickness throughout and the same standard conditions. As such, vitrinoids were distinguished on the basis of color as yellow, red, reddish-brown, and vitrinoids of any color with structure. The cell cavities of vitrinoids with structure are frequently filled by granular mineral matter, namely clay minerals. Sometimes fine grained micrinite is also observed in association with the mineral matter in the cell cavities of vitrinoids with structure. 

This is the classical method of extracting anthocyanins from plant materials. This procedure involves maceration or soaking of the plant material in methanol containing a small concentration of mineral acid (e.g., HC1). Methanol extraction is a rapid, easy, and efficient method for anthocyanin extraction. However, a crude aqueous extract with several contaminants is obtained, and methanol evaporation can result in hydrolysis of labile acyl linkages, which is aggravated by the presence of HC1. 

Attritus microscopic coal constituent composed of macerated plant debris mixed intimately with mineral matter and coalified. 

Fusinite microscopic coal constituent (maceral) with well-preserved cell structure and cell cavities empty or occupied by mineral matter. See also Maceral. 

Fusinite maceral distinguished by the well-preserved original form of plant cell wall structure, intact or broken, with open or mineral-filled cell lumens (cavities). 

Inertodetrinite maceral occurring as individual, angular, clastic fragments of other inertinite macerals, surrounded by other macerals, commonly vitrinite or minerals, and also distinguished by a reflectance higher than that of associated vitrinite. 

C OAL is AN extremely complex, heterogeneous material that is difficult to characterize. It is a rock formed by geological processes and composed of a number of distinct organic substances called macerals and of lesser amounts of inorganic entities called minerals. Each coal maceral and mineral has a unique set of physical and chemical properties that contributes to the overall behavior of coal. Although much is known about the mineral properties of coal, surprisingly little is known about the properties of the individual macerals. 

I now propose the new word "Maceral" (from the Latin macerare, to macerate) as a distinctive and comprehensive word tallying with the word "mineral". Its derivation from the Latin word to "macerate" appears to make it peculiarly applicable to coal, for whatever the original nature of the coals, they now all consist of the macerated fragments of vegetation, accumulated under water."... 

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