Percent solids, measurement

The percent solids measured in this way is an indirect measurement of the amount of volatile material in the sample that was driven off during the heating cycle. ASTM D1489 offers a test for determining the nonvolatile content of nonaqueous adhesives. 

Temperature-controlled refractometers are available for refractive index measurements of liquid samples and solutions. Such refractometers are stable and precise, and are applicable for both aqueous and volatile organic solutions such as those made with acetone or alcohol. A differential refractometer is used to obtain the exact percent solids of diluted solutions (nominal 1% polymer solutions or lower). In the case of both types of refractometers, the percent solids measurements are made relative to a calibration of the refractive indices of standard solutions of known concentration. 

Figure 55 indicates that the level of percent solids is extremely important in determining the proper separation, the higher the concentration, the coarser the separation. The correction factor is a relative measure of slurry viscosity and is affected by such parameters as particle present and particle shape. A feed that contains a large amount of clay would tend to shift the curve to the left, resulting in a coarser separation. In contrast, the absence of fines would shift the curve to the right and result in a finer separation. 

Percent solid settled In tests where adsorption and flocculation were determined simultaneously, the 200 ml sample was allowed to settle for 30 seconds and then 100 ml of the supernatant was removed using a suction device and after centrifugation analyzed for residual polymer concentration. The minimum level of detection was at 0.5 to 1 ppm and the reproducibility of the adsorption measurements was 2-3%. The settled 100 ml portion was analyzed for solid content. Flocculation due to polymer addition is measured by noting % solid settled as a function of polymer concentration. 

Swell Index and Percent Solubles Measurements. Polymer films were cast on polyester film at 25X solids with various post additives. The films were air dried (16-48 h) then cured for 3 and 10 min at 150 C In a converted oven. Small samples (50-100 mg) of film were weighed, soaked In dimethylformamide (DHF) for 1 h, briefly pat-dried and reweighed In an A1 weighing pan. The samples were then redried at 150 C (20 torr) or 170 C, 1 atm for 30 min. 

Analysis. The percent solids of each of the latexes was measured using a DuPont Model 950 Thermogravimetric Analyzer. Solution densities were determined using a Parr Mettler Model DMA-60 precision densitometer. The particle density was calculated from the solution density and the percent solids. 

The authors wish to acknowledge Sharon Kaffen for her synthesis of the PMMA latexes, Farrokh Malihi for QELS and turbidity measurements, C. M. Neag for percent solids analysis by thermogravimetry and C. B. Rakowski of SCM Pigments for the TEM measurements ... 

Estimate the percent solids content of the soil/sediment sample by measuring the volume of water evolved during the SDS... 

Float or Floated Sludge The concentrated material scooped or skimmed from the top of the flotation unit. The concentration is measured in percent solids, or mg/L. 

Density Nuclear gauges are the norm for density measurement. Nuclear density instruments require nuclear handling permits in most countries. Note that there are now some types that use very low level sources that do not require nuclear licensing. Density gauges should be recalibrated regularly as they are subject to drifting. Small flow applications may be able to use a coriolis meter to measure both mass and percent solids with one instrument. 

Percent solids oxidation (a measure of the total absorbed S02 that is oxidized to sulfate)... 

The cake analysis was corrected for the amount of adipic acid calculated to have been associated with the water in the wet cake based on weight percent solids in the cake and the measured concentration of adipic acid in the slurry liquor. A summary of test results is given in Table IV. 

Table IV also shows that the adipic acid makeup rate must be held below 15.4 lb/ton of SO2 absorbed in order to recover the cost of the additive when operating at 90 percent limestone utilization. This limit is increased only slightly, to 16.5 lb/ton of SO2, at a 97 percent level of limestone utilization. The makeup rate used in Table IV was obtained from two independent Shawnee measurements. One measurement is the average of eight runs (934-2A to -2H) made without fly ash and with 78 percent solids in the discharged sludge these runs required an average makeup rate of 9.95 lb/ton SO2. The second measurement was obtained from...

Level. Level sensors that depend on a pressure difference between two points, one submerged and one in the vapor, are subject to the same installation considerations described for pressure measurement. The inferred level measurement is more accurate when determined by a differential pressure transducer using remote diaphragms than when calculated from the difference between two absolute pressure transducers due to errors from calibration and transducer drift. In either case, the measurement is affected by changes in the weight percent solids in the solution an increase in the liquid density would be interpreted as an increase in the level. Ultrasonic level sensors are not affected by the slurry density but are sensitive to fouling. 

In Fig. 12.21, the solution viscosity is illustrated for Torlon AI-10 dissolved in NMP at various percent solids and measured at different temperatures. NMP is most commonly used due to its high solvency power, its low odor, and a relatively low level of toxicity. Diluents maybe added up to the level provided in Table 12.2 to lower viscosity and formulation cost. 

Tests to monitor the quality of production materials (QC tests) have relied on checking such properties as viscosity, percent solids, sag, pot life, and cure rate, in addition to measuring mechanical properties. The same tests have traditionally been used for receiving inspection procedures by the adhesive user however, there is now interest, particularly in the aircraft industry, to augment these by the use of physicochemical methods of analysis. These newer methods of control are expected to provide information of a more fundamental nature, useful in characterizing adhesives and diagnosing the causes of performance anomalies. 

Figure 3.21. TGA method for measuring percent solids and pigment volume concentration (PVC) in a coating ink [from Prime et al. (1988), with permission of the Federation of Societies for Coatings Technology].

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