Although bacterial heap leaching has been applied in the production practice of uranium and copper , the views on the role and mechanism of bacteria in heap leaching are not uniform. Some people think that it is a direct effect, some people think it is an indirect effect, and hold the latter view. People think that bacteria do not react directly with uranium, copper, etc., and bacteria should not be regarded as leaching agents of uranium and copper. At present, the tendency is that bacteria oxidize sulfide ore in ore to produce sulfuric acid and high - sulfur sulfate; high-sulfur sulfate is a good oxidant for low-grade uranium and copper sulfide ore, and sulfuric acid is a leaching agent for uranium and copper. Further, while the sulfur bacteria of the mine, the destruction of the original ore and the lattice structure, so that the original wrapped metal leaching solution is exposed, so that when a conventional metal does not leach heap leaching dissolution is improved Leach rate.
For bacterial heap leaching of uranium ore, the following chemical reactions are generally used:
2FeS 2 +2H 2 O+7O 2 
2FeSO 4 +2H 2 SO 4 (1)
4FeSO 4 +2H 2 SO 4 +O 2 2Fe 2 (SO 4 ) 3 +2H 2 O (2)
2S+2H 2 O+3O 2 2H 2 SO 4 (3)
Fe 2 (SO 4 ) 3 +UO 2 UO 2 SO 4 +2FeSO 4 (4)
The ferrous sulfate produced by the reaction formula (4) is oxidized again according to the reaction formula (2), and is circulated until the end of the leaching.
The chemical reaction of bacterial pretreatment of gold encapsulated in arsenopyrite is as follows:
4FeAsS+13O 2 +6H 2 O 4H 3 AsO 4 +FeSO 4
4FeSO 4 +2H 2 SO 4 +O 2 2Fe 2 (SO 4 ) 3 +2H 2 O
Fe 2 (SO 4 ) 3 +2FeAsS+4H 2 O+6O 2 2H 3 AsO 4 +4FeSO 4 +H 2 SO 4
The so-called bacterial pretreatment is essentially bacterial arsenic pyrite, which dissociates the gold encapsulated by arsenic pyrite. Therefore, in the experiment and production, the degree of arsenic removal in the pretreatment of the ore is often determined. The later ore is then subjected to gold cyanide leaching. It can be seen that when the bacteria are immersed in gold ore, the bacteria are not directly involved in the gold leaching process.
Scholars with direct effects often point out that the nickel ore is corroded by bacteria, nickel is dissolved, and the amino acid metabolite-amino acid can directly dissolve gold as an example to prove the correctness of their views. We believe that the role of bacteria in uranium, copper, and gold heap leaching is indirect; for sulfur, iron, and arsenic in ores, it is a direct effect.
High-temperature 1-color Pyrometer
This classification includes one color infrared pyrometers measuring range start from 700℃.
One color pyrometer determine the object temperature by receiving the sum of the narrow-band radiation energy, around(0.85~1.1)μm, emitted by the object. product detector nornally use si.
In one color mode, pyrometer measure the average temperature in an area. Instrument`s focal length range from 0.35m to infinite, the measurement distance can be infinite as long as the target size is large enough.
One color mode is suitable for measure below object: surface is relatively flat (not curved), and the measurement direction is less than 30°, surface physical and chemical state of the is stable (not in the process of oxidation, vaporization, and liquefaction), and the optical channel should with less dust and without blocking and attenuation. When the background temperature is higher than the measured temperature , the temperature can also be measured in the one color mode.
One color mode is used to measure large objects. Before measurement, make sure object can completely cover the field of view. Generally, object size should be greater than 20% of the field of view.
In this catalog, pyrometers applied to temperature measurement in the various industries, such as: inductioin heating,heat treatment,single crystal furnace, polycrystalline furnace, vacuum furnace, high temperature glass, metallugical forging, also suitable for temperature measurement in a good environment.
industrial infrared pyrometer, fixed infrared pyrometer, 1-color infrared pyrometer, monochromatic pyrometer
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