Float-sink data

Table I. Affinity of Elements for Pure Coal and Mineral Matter as Determined from Float—Sink Data...

The maceral concentrates obtained by float-sink methods from PSOC-828 and 1103 were somewhat less pure than the macerals obtained by hand or by centrifugation. For convenient comparison, the data obtained in the exchange reactions have been normalized to 100% maceral purity on the basis of the petrographic information presented in Table II using simultaneous linear equations. The normalized results are summarized in Table IV. 

ASTM analytical data presented in Table I indicate that the float-sink separation achieved an 84% and a 56% removal of ash from... 

The best known means of investigating and predicting theoreticalbeneficiationresnlts are the so-called washabil-ity cnrves, which represent graphically the experimental separation data obtained nnder ideal conditions in so-called float-sink tests. Float-and-sink analysis is also used to determine the Tromp curve, which measures the practical results of a density separation. The practical results of separation can then be compared with the ideal and a measure of efficiency calculated. 

To determine the partition curve for a cleaning operation, one needs the yield of clean coal from this operation and the results of float-sink tests for both products— that is, for the clean coal and the refuse. Such data allow the reconstituted feed to be calculated, and from this can be found the partition coefficients, which give the percentage of each density fraction reporting to reject. As seen in Fig. 22b, the particles with densities below 50 — 4 p and the particles of density above 50 + 4Ep report entirely to their proper products. The density fractions within 50 =b are misplaced. Material of density... 

The fly ash was from a burner using pulverized high volatile bituminous coal with a carbon content of —58 wt%. The carbon content was enriched by a float-sink procedure followed by extraction of mineral matter by HCI/HNO3/HF, called DEM-PCCl. This carbon was activated with steam at 850 °C for 60 min in a horizontal furnace, called AC-PCCl. Analytical data for these two carbons and a conunercial carbon, Darco Insul, are in Table 8.3. 

Float-and-sink analysis separation of crushed coal into density fractions using a liquid of predetermined specific gravity washability curves are prepared from these data (ASTM D-4371). 

Table V presents sulfur reduction data for two of the major coal seams in the region the Pittsburgh Seam and the Lower Kittanning Seam. Laboratory washability (float-and-sink) analyses of representative samples of these coals were used to determine potential sulfur reductions at various levels of cleaning. To assess the impact on regional SO2 emissions, sulfur reduction potentials were estimated for only those coals both produced and utilized in the Northern Appalachian Region. The "Present Level" of cleaning shown in the table represents estimated base-line values for the amount of sulfur in the coal product. These values take into consideration any coal cleaning that occurred, and are compared to coal sulfur contents that would result from more intense levels of cleaning. Each of the 11 major coal-producing seams in the region were evaluated in this manner.

Leaf discs have commonly been used for bioassays to determine if herbicides inhibit photosynthesis (Table 16.2). The simplest leaf-disc bioassay uses small discs cut from fully expanded cucumber or pumpkin cotyledons, floated in the light on a phosphate buffered medium containing suspected photosynthesis inhibitors.115 Qualitatively, if photosynthesis is inhibited, the leaf disc sinks. There are several variations of this method that can provide quantitative data. Evolution of O2 in the test solution can be measured with an oxygen electrode, CO2 induced pH changes colorimetrically determined with bromothymol-blue, or electrolyte leakage monitored with a conductivity meter. Leaf strips, algae, isolated chloroplasts, and duckweed (Lemna minor) have been used as test subjects. Although the bioassays presented in Table 16.2 are fairly easy to perform, few allelochemicals have been tested as possible inhibitors of photosynthesis. Many... 

Select a piece of plastic and add it to liquid 1. If it does not sink, push it under the surface with the forceps to make certain that trapped air bubbles are not keeping it afloat. Note whether it is more or less dense than the liquid. If it sinks in liquid 1, test the sample with liquid 2. Repeat until the sample floats in one of the liquids. Write down the approximate density of this sample based on your observations. Similarly test the other samples that you are provided and record your results. If you know the identity of these samples, compare your results with the data in Table 1 on the next page. If you are given an unknown plastic, deduce its possible composition using the data in Table 1. 

TABLE 6.12 Density (specific gravity) of some commercial deck boards. Data were obtained using sink/float method (see below)... 

The density of sea-water is almost independent of depth (1.040-1.045 g cm ) whereas that of liquid carbon dioxide increases with depth see Figure 3.9(b). Down to about 2500 m, liquid carbon dioxide is less dense than sea-water and tends to float upwards. At 2500-3000 m, liquid carbon dioxide is neutrally buoyant i.e., a transition zone in which it neither rises nor sinks), dependent on the sea temperature. Deeper than 3000 m, the liquid is denser than sea-water and sinks downwards to the ocean floor, where it accumulates as a lake, over which a solid layer of crystalline hydrates slowly forms as an ice-like combination of carbon dioxide and water. Within its stability range (low temperature, high pressure), solid C02-hydrate would inspire greater confidence as a permanent store than dissolved or liquid carbon dioxide, although there are few data to say how rapidly carbon dioxide would be leached out by sea-water. 

Typical data shown in Tables 6 and 7 for an E-CO and a corresponding LDPE homo-polymer, demonstrates the similarities between the two resins. In appearance, as film or extruded items, they are also seemingly identical. It is now known that the C=0 groups fit into the PE crystal lattice and hence have little effect on the overall crystallinity. However, E-CO density increases with increases in CO content. It has been noted that at around 16 % CO, E-CO will not float in fresh water, and at about 20% CO, the copolymer will sink in salt water. For rapid photodegradability of marine litter, those CO levels are the upper limitations to assure exposure to the light necessary for photodegradation. 

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