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A separation process is a method that converts a mixture or a solution of chemical substances into two or more distinct product mixtures, [1] a scientific process of separating two or more substances in order to obtain purity. At least one product mixture from the separation is enriched in one or more of the source mixture's constituents.
The oldest form of mineral processing practiced since the Stone Age is hand-picking. Georgius Agricola also describes hand-picking is his book De re metallica in 1556. [6] Sensor-based sorting is the automation and extension to hand picking. In addition to sensors that measure visible differences like color (and the further interpretation of ...
Gravity separation is one of the oldest technique in mineral processing but has seen a decline in its use since the introduction of methods like flotation, classification, magnetic separation and leaching. Gravity separation dates back to at least 3000 BC when Egyptians used the technique for separation of gold.
Hand sorting was the first method used in the history of waste sorting. [2] Waste can also be sorted in a civic amenity site. Waste segregation is the division of waste into dry and wet. Dry waste includes wood and related products, metals and glass.
Purification in a chemical context is the physical separation of a chemical substance of interest from foreign or contaminating substances. Pure results of a successful purification process are termed isolate. The following list of chemical purification methods should not be considered exhaustive.
This was originally done primarily by hand, but hand picking was gradually supplanted after 1910 by improved screens and jigs. [3] Although breaker boys worked at all levels of the coal breaker, most of the removal of impurities by hand occurred on this level. [4]
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Picking is done by hand when a higher quality tea is needed, or where labour costs are not prohibitive. Depending on the skill of the picker, hand-picking is performed by pulling the flush with a snap of the forearm, arm, or shoulders, with the picker grasping the tea shoot using the thumb and forefinger, with the middle finger sometimes used ...