Extraction equipment used in solvent extraction in analytical chemistry
Solvent extraction is also called the liquid -
Liquid extraction, is commonly used in modern analytical chemistry and one of important separation method.
Its advantage is simple, rapid and easy to manipulate and automation, as well as extraction matrix elements, separation and enrichment of trace elements, with the development of organic synthesis chemistry and achievements, the selection of extraction agent type increasing, so the selection of extraction system is also more easily achieve high selectivity and extraction rate, solvent extraction and spectrophotometry, atomic absorption method, electrochemical method, X-ray fluorescence spectrometry, emission spectrometry, advances the separation and determination of selectivity and sensitivity.
solvent extraction principle solvent extraction of one phase as an aqueous solution, another phase for organic solvent, both mutual miscibility.
Isolated substance in organic solvents from aqueous solution, and immediately to form two layers.
Organic solvent is in the upper or the lower, is determined by its relative density is less than or greater than the water.
in a solvent in the liquid mixture solution, make the solution of the components for all or part of the process is called extraction separation.
Solvent extraction is extracted from dilute solution material is an effective method.
Widely used in metallurgical and chemical industries.
In the gold industry, solvent extraction method was used to extract gold, silver has a lot of research, in foreign countries, the mature technology has industrial application for many years.
Using extraction method to extract copper, zinc from cyanide wastewater research also more reports.
from nonferrous metal cyanide in cyanide solution extraction complex generally use high polymer organic amine, such as chlorinated trialkyl amine (
, diluent for high carbon alcohol is sulfonated kerosene, solvent.
Water is to deal with the waste water.
Similar to absorb manipulation, extraction process for the event phase balance limit.
This is similar with ion exchange and liquid membrane method.
But ion exchange method using solid ion exchange resin absorption material;
The liquid film method is using a water-in-oil (
Alkali solution to absorb hydrogen cyanide)
Extraction method used in the absorber are composed of organic matter, the mass density must be with aqueous solution or raw material liquid has quite big difference, so that the two phase can more easily separated by gravity, the boiling point of organic phase have higher, to ensure that the organic matter in use process not loss too much.
extraction process is a mass transfer process of solutes from aqueous phase to the organic phase, until the balance.
Therefore require extraction equipment can fully make water diffusion in a relatively short time, in the material to the organic phase, and requires organic phase viscosity don't too big, lest be absorbed material to produce larger concentration gradient in the organic phase and hinder the absorption process.
extraction process for the enrichment of the water phase of a substance or several organic phase extraction phase.
After several extraction separation of a substance or material of water phase is called extraction liquid.
by reverse extraction to extract phase extract isolated to the organic phase can recycle.
For copper cyanide complex ion extraction phase, caustic soda solution available from copper complex ion extraction phase extraction, containing high concentration of copper cyanide complex solution.
By electrolytic process can be the solution of copper deposits, and greatly reduced the electrolytic copper concentration waste liquid can be used for cyanide process.
Can also be used by acidification recycling method and treatment of copper cyanide complex extract, recovery of cyanide and copper, the waste liquid with lime neutralization, clarifies, return to the cyanide process.
Extraction residue that is after extraction processing of water phase after oil removal can be used for cyanide process.
in order to complete extraction process for a limited time, usually a multi-stage extraction and multistage reverse extraction.
Thus increasing molar concentration in the organic phase is separated and mass transfer rate of progress.
extracting all the equipment there are four main types, namely, mixer settler, packed tower, sieve plate tower, spray tower, in recent years, again plus pulse of energy packed tower and sieve plate tower and smaller. cwl type centrifugal extraction separation density difference machine.