Inorganic extractant

Carbon dioxide is the most common inorganic extractant used for the extraction of organic compounds in soil. Under pressure, it remains in the liquid state and can be used to extract organic compounds from soil. When the pressure is released, the carbon dioxide becomes a gas and is thus removed from the extracted components. An additional benefit is that liquid carbon dioxide is converted to gas at relatively low temperatures, thus limiting the loss of... 

Inorganic extractions seem to have come into practical use without any great notice. Although Peligot in 1842 reported that uranyl nitrate could be recrystalhzed from ether, he never mentioned extraction of this salt from aqueous solutions. In textbooks after 1870, however, it is stated briefly that ether can even withdraw sublimate (HgCy from aqueous solution. It was also reported, for example, that cobalt thiocyanate is weakly extracted by ether, better by amyl alcohol, and even better by a mixture of both. 

Thus far, this review has focused completely on organic extractables and leachables, however it is also possible to have inorganic extractables and leachables associated with pharmaceutical packaging and drug products. Inorganic extractables/leachables can arise from residual... 

Inorganic extractables/leachables would include metals and other trace elements such as silica, sodium, potassium, aluminum, calcium, and zinc associated with glass packaging systems. Analytical techniques for the trace analysis of these elements are well established and include inductively coupled plasma—atomic emission spectroscopy (ICP-AES), ICP-MS, graphite furnace atomic absorption spectroscopy (GFAAS), electron microprobe, and X-ray fluorescence. Applications of these techniques have been reviewed by Jenke. " An example of an extractables study for certain glass containers is presented by Borchert et al. ". ... 

L. Bulgariu, D. Bulgariu, Extraction of metal ions in aqueous polyethylene glycol—inorganic salt two-phase systems in the presence of inorganic extractants correlation between extraction behaviour and stability constants of extracted species, J. Chromatogr. A 1196—1197 (2008) 117. 

Extraction using ion association (ion-pair). Neutral complexes can be formed through ion association (ion-pair) and extracted from the aqueous solution into an organic solvent. Ion associations with inorganic extracts encompass a wide range of extraction schemes. General sub-groups include... 

The nature of the solvent is of special importance for inorganic extractions. There are several criteria that should be evaluated when choosing a solvent for an inorganic extraction. The solvent should have the following characteristics ... 

Inorganic extraction and purification Mixed cultures without sterilization... 

The infonuation that can be extracted from inorganic samples depends mainly on tlie electron beam/specimen interaction and instrumental parameters [1], in contrast to organic and biological materials, where it depends strongly on specimen preparation. 

In the isolation of organic compounds from aqueous solutions, use is frequently made of the fact that the solubility of many organic substances in water is considerably decreased by the presence of dissolved inorganic salts (sodium chloride, calcium chloride, ammonium sulphate, etc.). This is the so-called salting-out effect. A further advantage is that the solubility of partially miscible organic solvents, such as ether, is considerably less in the salt solution, thus reducing the loss of solvent in extractions. 

CAUTION. Ethers that have been stored for long periods, particularly in partly-filled bottles, frequently contain small quantities of highly explosive peroxides. The presence of peroxides may be detected either by the per-chromic acid test of qualitative inorganic analysis (addition of an acidified solution of potassium dichromate) or by the liberation of iodine from acidified potassium iodide solution (compare Section 11,47,7). The peroxides are nonvolatile and may accumulate in the flask during the distillation of the ether the residue is explosive and may detonate, when distilled, with sufficient violence to shatter the apparatus and cause serious personal injury. If peroxides are found, they must first be removed by treatment with acidified ferrous sulphate solution (Section 11,47,7) or with sodium sulphite solution or with stannous chloride solution (Section VI, 12). The common extraction solvents diethyl ether and di-tso-propyl ether are particularly prone to the formation of peroxides. 

The high sodium ion concentration results in facile crystallisation of the sodium salt. This process of salting out with common salt may be used for recrystallisation, but sodium benzenesulphonate (and salts of other acids of comparable molecular weight) is so very soluble in water that the solution must be almost saturated with sodium chloride and consequently the product is likely to be contaminated with it. In such a case a pure product may be obtained by crystallisation from, or Soxhlet extraction with, absolute alcohol the sul-phonate is slightly soluble but the inorganic salts are almost insoluble. Very small amounts of sulphones are formed as by-products, but since these are insoluble in water, they separate when the reaction mixture is poured into water ... 

Anionic extractants are commonly based on high molecular weight amines. Metal anions such as MnO or ReO can be exchanged selectively with inorganic anions such as Cl or The equiHbrium for a quaternary onium compound of organic radicals R for two anion species A and B ... 

Extraction of Nonmetallic Inorganic Compounds. Phosphoric acid is usually formed from phosphate rock by treatment with sulfuric acid, which forms sparingly soluble calcium sulfate from which the phosphoric acid is readily separated. However, in special circumstances it may be necessary to use hydrochloric acid ... 

PhenoHc-based resins have almost disappeared. A few other resin types are available commercially but have not made a significant impact. Inorganic materials retain importance in a number of areas where synthetic organic ion-exchange resins are not normally used. Only the latter are discussed here. This article places emphasis on the styrenic and acryHc resins that are made as small beads. Other forms of synthetic ion-exchange materials such as membranes, papers, fibers (qv), foams (qv), and Hquid extractants are not included (see Extraction, liquid-liquid Membrane technology Paper.). 

The development of a suitable solvent system is important for successful operation. Solvent systems generally consist of at least the following components extractant, diluent, inorganic salts or acids, and water. The relative optimization of these components yields the best conditions with which to achieve separation. A key factor to success is the choice of the appropriate extractant. Many extractants may be used for REE separation. These may be divided into three groups on the basis of the mechanisms involved. These extractants are tisted in Table 7. 

Pyrolysis. Heating in the absence of oxygen releases moisture at low temperatures, carbon dioxide at temperatures >200° C, and a variety of gaseous products at very high temperatures. Acid washing of the raw coal is used to remove extractable cations, followed by treatment with selected cations. Yields of CO2, CO, CH, H2, and H2O depend on the amounts of inorganic species in the coal (42). 

The scientific basis of extractive metallurgy is inorganic physical chemistry, mainly chemical thermodynamics and kinetics (see Thermodynamic properties). Metallurgical engineering reties on basic chemical engineering science, material and energy balances, and heat and mass transport. Metallurgical systems, however, are often complex. Scale-up from the bench to the commercial plant is more difficult than for other chemical processes. 

---