Ash Fusion Test

ASTM dass/group Seam/origin SIO2 Al,0, TlOz FeaOs M9O CaO NasO KjO P,0, SO3 IDT ST HT FT 

FT fluid lempeiatuce, HT hemisphetical temperature, IDT initial deformation temperature, IL Illinois, KY Kentucky, HDiNordt Dakota, PA Pertnsylvania, ST softening temperature, WV We t Virginia, WY Wyoming. 

The reported temperatures are, of course, strongly dependent on the ash composition (formation of eutectics) and the applied atmosphere. 

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Crystallization of the homogeneous glasses was performed in a vertical tube furnace with a controlled atmosphere (002/ 2 with a total flow rate of 200 ml per min.). This is tne same atmosphere used in the ash fusion test ( ). The quenched sample was analyzed by petrographic microscopy, powder X-ray diffraction and chemical analysis (to determine the ferrous/total iron ratio) using the method of Hey (2). 

Despite these restrictions however, ash fusion tests are a useful way of assessing the slagging propensity associated with different coal samples. 

The most basic test in this respect is the ash fusion test (e.g., ASTM D-1857 [82]). The ash, which is prepared under controlled conditions, is pressed to a pyramid, cone, or cylinder and exposed to temperatures up to 1600 °C under an oxidizing or reducing gas atmosphere. While heating with 5 or 8K/min, the changes in the shape of the specimen are observed optically and usually recorded by a camera. Figure 3.4 presents certain characteristic shapes that are associated to the reported temperatures. Their appearance and technical impact can be summarized as follows [11,16] ... 

The color of the ash before the ash fusion test is reported to be an indicator for its fluid temperature. Highly colored ash shows low fluid temperatures and nearly white ash indicates high fusion points [10]. 

Hence, if the ash fusion test shows a short slag, the influence of the solids can be respected by the Einstein-Roscoe equation [103] ... 

The results of monitoring the temperature profiles and ash fusion temperatures of the ash resulting from the test coals burned in the different boilers indicated that the effect of boiler temperature and ash fusion characteristics of the coal on the leaching and sorbent characteristics should be examined. This could be carried out through a comparison of the leaching and sorbent characteristics of the fly ash produced in the 11 boiler with that produced in 12 boiler and the fly ash produced in the A boiler with that produced in the C and D Boilers, respectively. 

The activity was also tested where char combustion was conducted in the regenerator. The average conditions for this run are given in Table VI. In this run 32 lbs. of char were burned, thereby exposing the acceptor to 0.73 lb. ash/lb. MgO CaO inventory. The combustion was trouble free, giving essentially flat temperature profiles and complete burnout of the carbon. No ash fusion difficulty was experienced. 

Because of the broad similarity to coal, tests to assess the potential for fouling (and/or slagging) have been based on those developed for coal, for instance the temperature indicators described in Section 16.3.2.1 Dabron and Rampling [1988] have given some ash fusion data for refuse derived fuel from three different UK incinerators and compared them with a coal as presented in Table 16.16. 

The development status of process control instrumentation lags that of the quality control instruments significantly Nuclear density gauges function in the coal preparation plant environment The slurry concentration meter has application in the intermediate and fine sized coal cleaning circuits and needs to be tested in a preparation plant Other devices, such as ash monitors to control the operation of heavy media baths or jigs are not available and instruments developed for other process industries are not suitable for use in coal preparation plants Modeling studies of the various unit operations are required in order to ascertain the fundamental parameters required to automate the control of these systems Primary process control instrument needs include ash, sulfur, and moisture monitors secondary needs include an on-line washability and ash fusion measurement ... 

Testing of different soil types on Alamo switchgrass using hand cut samples show that teat content variations between clay, sandy loam, and sandy soil ranged from 18.75 MJ/kg to 18.97 MJ/kg (8082 Btu/lb to 8175 Btu/lb) on a dry basis ash fusion tenq)eratures ranged from 1112°C to 1138 C (2034°F to 2082 EO- Fertilization of Alamo switchgrass from 0... 

Haslam et al. [32] reported the determination of Al in polyolefins by AAS. Typical AAS tests on rubber compounds involve several steps. The sample is combusted, and the resulting ash is dissolved in distilled de-ionised water. The solution is then used for AAS [126]. AAS or EDS can also be used for element analysis of filler particles. In order to determine the uniformity of tin compounds in polychloroprene after milling and pressing, Hornsby et al. [127] have ashed various pieces from one composition. After fusion of the residue with sodium peroxide and dissolution in HC1, the Sn content was determined by means of AAS. Typical industrial AAS measurements concern the determination of Ca in Ca stearate, Zn in Zn stearate, Ca- and Zn stearate in PE, Ca and Ti in PE film or Al and V in rubbers. 

Distinction of Colophony from Resinates—Resinates of calcium, lead, manganese and zinc, which are the commonest of those obtained by fusion—i.e. by dissolving the corresponding metallic oxide in the colophony fused at a convenient temperature—are very similar in appearance to ordinary colophony, but they are easily distinguishable by determining the ash and by testing their solubility in alcohol.1... 

In some test methods it is recommended that the color of the ash be noted, as it gives an approximate indication of the fusion point. Generally, highly colored ash has a low fusion point, whereas white ash, provided that there are essentially no basic oxides, has a high fusion point. 

There are two other reasons why alkalis are important. First, in mineral processing, minerals such as chromite require fusing with an alkali to convert the element being extracted into a soluble form. Both sodium carbonate and potassium carbonate are used as fusion mixtures. Second, in the manufacture of glass, silica is fiised with either soda ash or potassium carbonate. In our view, ashes with a very high alkali content, such as those of banana wastes, can be used in place of the commercially-available alkalis. Some tests are under way to confirm this hypothesis. 

Some instrumental methods (INAA, XRFA) analyse directly the aerosol filter or portions of filters. Recently such approach is intensively tested for other methods especially ETAAS. For the majority of instrumental methods however treatment of the filter is required leading to a liquid extract. Wet ashing with different acidic mixtures is very popular though dry ashing in a furnace, followed by acid dissolution is also used. The choice of the method depends not only on the measurement technique and the range of substances to be analyzed but also on the chemical form of the element (Kneip and Kleinman, 1982). For example high temperature secondary aerosols may contain refractory oxides or silicates and the treatment requires fusion or hydrofluoric acid dissolution. 

It is well known that corrosion of refractories used in the superstructure of glass melting furnaces can occur due to reaction with components of raw batch (also known as batch carryover) such as silica sand and soda ash and also from vapor phase species, such as NaOH. While there is a standard test available from ASTM for corrosion of refiectories from vapors (C987), there is no standard test available for testing corrosion from batch carryover. The ASTM standard, C987, requires the use of either alumina or platinum crucible for melting batch components that produce vapors, such as sodium carbonate. For the purpose of this study, the authors chose to prepare crucibles directly from the fusion-cast AZS and vibro-cast AZS products. 

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