Prior Separation Technology

In 1999 a new type of annular chromatograph was presented by Prior Separation Technology GmbH, a spin-off company of Prior Technology GmbH. At the same time the selling of the machine under the brand name of P-CAC started. 

Fig. 2. Picture of a commercially available P-CAC system from Prior Separation Technology GmbH...

Compared to the continuous annular chromatography systems sold by Isopro International and used throughout the ORNL studies, the P-CAC units developed by Prior Separation Technology feature several design modifications which will be presented hereafter. As can be seen from Fig. 3, the P-CAC system consist of three major parts the P-CAC head, the annular column, and the drive including the control panel. Figure 3 represents a schema of the laboratory sized P-CAC used as a Research and Development tool. 

Rogner K (1995) Personal communications (with Prior Separation Technology)... 

Analyses of alloys or ores for hafnium by plasma emission atomic absorption spectroscopy, optical emission spectroscopy (qv), mass spectrometry (qv), x-ray spectroscopy (see X-ray technology), and neutron activation are possible without prior separation of hafnium (19). Alternatively, the combined hafnium and zirconium content can be separated from the sample by fusing the sample with sodium hydroxide, separating silica if present, and precipitating with mandelic acid from a dilute hydrochloric acid solution (20). The precipitate is ignited to oxide which is analy2ed by x-ray or emission spectroscopy to determine the relative proportion of each oxide. 

A major breakthrough in separation of products from catalyst, in particular heat sensitive products, came with the discovery of the NAPS or Non-Aqueous Phase Separation technology. NAPS provides the opportunity to separate less volatile and/or thermally labile products. It is amenable to the separation of both polar [14] and non-polar [15] products, and it offers the opportunity to use a very much wider array of ligands and separation solvents than prior-art phase separation processes. The phase distribution characteristics of the ligand can be tuned for the process. Two immiscible solvents are... 

Cyclodextrin hydrate was purchased from Acros Organics, Fisher Scientific Company, and was used without further purification or drying (Rf = 0.41, 2-PrOH/H20/EtOAc/concd NH4OH 5 3 1 1). p-Cyclodextrin and the title compound were dissolved in water, spotted on silica gel 60 F254 aluminum-backed plates (EM Separations Technology), and dried on a hot plate prior to development in the solvent systems indicated. 

Inclined plate clarification is a traditional separation technology that has been used for decades to remove suspended solids from a liquid stream in various types of systems including traditional precipitation [12]. In the semiconductor industry, the clarifier is commonly used in fluoride waste treatment systems where calcium fluoride precipitate is concentrated prior to dewatering in a press, or in assembly/test operations to separate silicon fines from backgrind operations. The clarifier will concentrate the solid phase of slurry like a UF, but unlike the UF or MF, the clarifier may require the addition of a chemical polymer to facilitate the agglomeration of the suspended solids so that they settle and concentrate. Polymer addition adds another level of complexity to the waste treatment system. The clarifier does not provide a physical barrier to prevent the transport of solids to downstream equipment, so it may be necessary to install a UF or MF downstream of the clarifier to capture extraneous particles or to protect the downstream equipment from clarifier upsets. 

Unfortunately, as will become clear to readers, there is no universal green solvent and users must ascertain their best options based on prior chemistry, cost, environmental benefits and other factors. It is important to try and minimize the number of solvent changes in a chemical process and therefore, the importance of solvents in product purification, extraction and separation technologies has been highlighted. 

Conventional lube manufacturing employs mostly separation technology originally developed prior to World War II and significantly improved since then. The steps usually are... 

Abstract. The applications of rare earth elements (REE) in various technological fields are reviewed, with emphasis on the importance of the knowledge of the chemical composition of the materials used. Nuclear neutron activation (NNA), atomic absorption spectrometry (AAS), inductively coupled plasma-atomic emission spectrometry (ICP-AES), inductively coupled plasma-mass spectrometry (ICP-MS) and x ray fiuorescence spectrometry (XRF) are the most frequently used analytical techniques for determining REE. Complex matrices require the prior separation of the analytes by column chromatography. 

Certain techniques for the application of thermodynamics in separation technology are introduced in Chapter 11, for example, the concept of residue curve maps, a general procedure for the choice of suitable solvents for the separation of azeotropic systems, the verification of model parameters prior to process simulation and the identification of separation problems. 

Nevertheless, there are many other mixtures of surfactants that can be analysed by classical methods without prior separation. Mixtures of surfactants of one type, e.g. the anionic, cationic and nonionic fractions recovered from an ion-exchange column, can often be so treated, the most notable exception being mixtures of different kinds of sulphonated hydrocarbons, which require high-tech methods. Mixtures of nonionics and of cationics are, however, not often encountered in practice, but a fair proportion of mixtures of surfactants of different classes can be analysed without recourse to high technology, and this is of considerable practical use. 

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