Author: admin
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physical chemistry
Physical chemistry is the study of macroscopic and microscopic phenomena in chemical systems in terms of the principles, practices, and concepts of physics such as motion, energy, force, time, thermodynamics, quantum chemistry, statistical mechanics, analytical dynamics and chemical equilibria. Physical chemistry, in contrast to chemical physics, is predominantly (but not always) a supra-molecular science, as the majority of the principles on which it was founded relate to the bulk rather than the molecular or atomic…
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Synthesis of organic compounds
Once the properties endowed upon a substance by specific structural units called functional groups are known, it becomes possible to design novel molecules that may exhibit desired properties. The preparation, under controlled laboratory conditions, of specific compounds is known as synthetic chemistry. Some products are easier to synthesize than to collect and purify from their natural sources. For…
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Organic compounds in nature
A major focus of organic chemistry is the isolation, purification, and structural study of naturally occurring substances, since many natural products are simple organic molecules. Simple carbon-containing compounds produced by photosynthesis—the process by which carbon dioxide and water are converted to oxygen and compounds known as carbohydrates—form the raw material for the myriad organic compounds found in the plant and animal kingdoms. Such compounds include formic acid (HCO2H) in ants, ethyl alcohol (C2H5OH) in…
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Areas of specialization
Organic chemistry is the largest area of specialization among the various fields of chemistry. It derives its name from the fact that in the 19th century most of the carbon compounds then known were considered to have originated in living organisms. When combined with variable amounts of hydrogen, oxygen, nitrogen, sulfur, phosphorus, or other elements, the structural possibilities of carbon compounds become limitless.…
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organic chemistry
Organic chemistry, field of science concerned with the composition, properties, and structure of chemical elements and compounds that contain carbon atoms. Carbon is unique in the variety and extent of structures that can result from the three-dimensional connections of its atoms.
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Dewatering
Concentrates and tailings produced by the methods outlined above must be dewatered in order to convert the pulps to a transportable state. In addition, the water can be recycled into the existing water circuits of the processing plant, greatly reducing the demand for expensive fresh water. Filtration Filtration is the separation of a suspension into a solid…
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Flotation separation
Flotation is the most widely used method for the concentration of fine-grained minerals. It takes advantage of the different physicochemical surface properties of minerals—in particular, their wettability, which can be a natural property or one artificially changed by chemical reagents. By altering the hydrophobic (water-repelling) or hydrophilic (water-attracting) conditions of their surfaces, mineral particles suspended…
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Gravity separation
Gravity methods use the difference in the density of minerals as the concentrating agent. In heavy-media separation (also called sink-and-float separation), the medium used is a suspension in water of a finely ground heavy mineral (such as magnetite or arsenopyrite) or technical product (such as ferrosilicon). Such a suspension can simulate a fluid with a higher density than…
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Concentration
Concentration involves the separation of valuable minerals from the other raw materials received from the grinding mill. In large-scale operations this is accomplished by taking advantage of the different properties of the minerals to be separated. These properties can be colour (optical sorting), density (gravity separation), magnetic or electric (magnetic and electrostatic separation), and physicochemical…
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Comminution
In order to separate the valuable components of an ore from the waste rock, the minerals must be liberated from their interlocked state physically by comminution. As a rule, comminution begins by crushing the ore to below a certain size and finishes by grinding it into powder, the ultimate fineness of which depends on the…