Sampling particulate solids

Typical examples of gaseous samples include automobile exhaust, emissions from industrial smokestacks, atmospheric gases, and compressed gases. Also included with gaseous samples are solid aerosol particulates. 

Solid-Phase Extractions In a solid-phase extraction the sample is passed through a cartridge containing solid particulates that serve as the adsorbent material. For liquid samples the solid adsorbent is isolated in either a disk cartridge or a column (Figure 7.17). The choice of adsorbent is determined by the properties of the species being retained and the matrix in which it is found. Representative solid adsorbents... 

For inductively coupled plasma atomic emission spectroscopy (ICP-AES) the sample is normally in solution but may be a fine particulate solid or even a gas. If it is a solution, this is nebulized, resulting in a fine spray or aerosol, in flowing argon gas. The aerosol is introduced into a plasma torch, illustrated in Figure 3.21. 

Estimating Minimum Sample Quantity for Moisture Measurement Estimates of material quantity for testing moisture content depend on mechanisms of moisture distribution in the material. Moisture is physically retained on particle surfaces, chemically adsorbed on surfaces and within pores of particulate solids, and contained as an internal constituent of solids. Significant internal moisture is most often encountered in organic and agricultural source materials. 

The cost of an electric-drive rotaiy-cutter sample of the smallest size manufactured—suitable for gravity sampling of fine particulate solids or shiny flow—including timer and control unit was approximately 5,000 in 1996. 

Minkkinen, P., Evaluation of the Fundamental Sampling Error in the Sampling of Particulate Solids, Analytica Chimica Acta 196, 1987, 237-245. 

P. Minkkinen, Evaluation of the fundamental sampling error in the sampling of particulate solids. Anal. Chim. Acta, 196, 237-245 (1987). 

The control of processes involving the treatment of solids generally requires means for careful sampling and analysis of solids and slurries at various points in an operation. Unlike liquids, particulate solids are not homogeneous. The composition of individual particles will vary with particle size and particle density. It follows that care must be... 

In contrast, when sampling bulk material, the material cannot generally be viewed as a set of distinct units. For example, we sample liquids from tanks, drums, and pipelines, and particulate solids such as ore, powders, and soil. Individual units cannot be identified for sampling. Rather, we must decide on a sample mass Mg or volume the chemical sample size. Further, we must be concerned about whether to composite samples, and, if so, how much to include in each increment of the composite. An additionaJ complication is the restriction on the sample mass that must be used in a chemical analysis due to the method or instrumentation. In fact, a subsample is usually taken in the lab. 

Especially for process control it is often necessary to determine particle size distributions of particulate solids that are in motion. The material may be transported either on or by a moving device, e.g. belt, vibrating, or drag chain, screw, bucket, and other conveyors, or in a carrier medium such as gases or liquids it may also fall freely or slide down chutes of various configurations. The best method to obtain a representative sample from such situations is to temporarily divert the entire stream into a container. If the particulate matter... 

That portion of a sample of particulate solids which is between two particle sizes (see cut) or in a stated range (e.g. fine, coarse, etc.). 

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