To separate one or more components in the mixture, the mixture should be contacted with the other phases, the process is known as Extraction. Another phase is contacted may be a gas-liquid, vapor-liquid, liquid-liquid and solid-fluid. The extraction process itself is divided into two kinds, namely, liquid-liquid extraction and solid-liquid extraction (leaching). Solvent extraction (liquid-liquid extraction) is often used as an alternative to splitting than by distillation or evaporation. For example, acetic acid can be separated from the water by distillation or by extraction using an organic solvent.
Most biological compounds, organic and inorganic form in the mixture of various components in solids. For separating solute (substance that want extracted) desirable and undesirable from a solid, solid phase is contacted with a liquid / liquid. The second phase will be in contact and solute diffuses from the solid to the liquid phase resulting in solute that had to be in solid can be separated. The separation process is called leaching. In leaching, when the unwanted components are separated from the solid by using the so-called washing water.
Leaching is widely used in various industries. In the industrial processes of biological and food products are separated from their natural structure leaching process. For example, sugar is produced from leaching from sugar cane or sugar beets using water. In the production of vegetable oil, organic solvents such as hexane, acetone, and ether is used to extract oil from peanuts, soybeans, sunflower seeds, cotton seeds, and so on. In the pharmaceutical industry, a variety of different pharmaceutical products produced by the process of leaching plant roots, leaves, or stems. In addition to a variety of uses over the leaching is also found in the metal processing industry. Typically useful metal is usually in a mixture with the number of unwanted constituents are quite large. Leachingdipakai to separate the metal as a salt dissolved. For example salt-leaching copper from ores containing various metals using sulfuric acid or ammonia solution.
Preparation of a solid which will be dependent on the proportion of solute leaching existing distribution in the solid and the nature of the solid. When dissolved compounds surrounded by an insoluble material, the solvent must diffuse into and then contact and solutes dissolve and then diffuse out.
Biological materials typically have a cellular structure and solutes are in the cell. Leaching process takes place relatively slowly because the cell wall causing an obstruction to diffuse. For that biological materials that would normally dileaching cut thin strips or reduced in size in advance so that the cells divided so that diffusion can take place more quickly. Examples in for extracting sugar from sugar cane, sugar cane should be cut first.
In the leaching process, the mechanism is transferred to the surface of a solid solvent, then the solvent diffuses or enter into a solid. Then, there is the solid solute diffuses into the solvent. Then solute that has been dissolved in a solvent diffuses to the surface and then transferred to a solvent. Generally, the mechanism of the extraction process is divided into 3 parts:
Phase change solute to dissolve into a solvent, for example, from solid to liquid.
Most biological compounds, organic and inorganic form in the mixture of various components in solids. For separating solute (substance that want extracted) desirable and undesirable from a solid, solid phase is contacted with a liquid / liquid. The second phase will be in contact and solute diffuses from the solid to the liquid phase resulting in solute that had to be in solid can be separated. The separation process is called leaching. In leaching, when the unwanted components are separated from the solid by using the so-called washing water.
Leaching is widely used in various industries. In the industrial processes of biological and food products are separated from their natural structure leaching process. For example, sugar is produced from leaching from sugar cane or sugar beets using water. In the production of vegetable oil, organic solvents such as hexane, acetone, and ether is used to extract oil from peanuts, soybeans, sunflower seeds, cotton seeds, and so on. In the pharmaceutical industry, a variety of different pharmaceutical products produced by the process of leaching plant roots, leaves, or stems. In addition to a variety of uses over the leaching is also found in the metal processing industry. Typically useful metal is usually in a mixture with the number of unwanted constituents are quite large. Leachingdipakai to separate the metal as a salt dissolved. For example salt-leaching copper from ores containing various metals using sulfuric acid or ammonia solution.
Preparation of a solid which will be dependent on the proportion of solute leaching existing distribution in the solid and the nature of the solid. When dissolved compounds surrounded by an insoluble material, the solvent must diffuse into and then contact and solutes dissolve and then diffuse out.
Biological materials typically have a cellular structure and solutes are in the cell. Leaching process takes place relatively slowly because the cell wall causing an obstruction to diffuse. For that biological materials that would normally dileaching cut thin strips or reduced in size in advance so that the cells divided so that diffusion can take place more quickly. Examples in for extracting sugar from sugar cane, sugar cane should be cut first.
In the leaching process, the mechanism is transferred to the surface of a solid solvent, then the solvent diffuses or enter into a solid. Then, there is the solid solute diffuses into the solvent. Then solute that has been dissolved in a solvent diffuses to the surface and then transferred to a solvent. Generally, the mechanism of the extraction process is divided into 3 parts:
Phase change solute to dissolve into a solvent, for example, from solid to liquid.
- Diffusion through a solvent in the pores - pores for the subsequent exit of the particles.
- Finally this solute displacement of about particles in the solution to the whole.
- Every part of this mechanism will affect the speed of extraction, but the first part takes place quickly so the overall extraction speed can be ignored.
So the leaching process to do three things:
1. Dissolution solutes.
2. Separation of the solution to the solid residue.
3. Wash the solid residue
Bibliography
Geankoplis, C.J. 2003, Transport Processes and Separation Process Principles (includes Unit Operations), 4th ed., Pp 776-777, 802-806, Prentice Hall, New Jersey
Budhikarjono, Kusno, 1996, Dictates Lecture Tools Industrial Chemistry, first edition, pp. 99-101, Institute Ten November, Surabaya ..
Keywords: Leaching, solid-liquid extraction, Solute, Solvent, Solvent, Chemical Engineering Operations
See Also: Drying , Factors that need to be noticed in the leaching process
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