Year1
- 型号：
- XHQ50
- 品牌：
- 新达
- 加工定制：
- 是
Product introduction of environmentally friendly quicklime digester: <. Structural principle of environmentally friendly quicklime digester< The environmentally friendly quicklime digester feeds lime powder from the feeding system, and the screw conveys it evenly to the mixing area, and the water adding system supplies water quantitatively , lime powder and water are mixed and pushed to the discharge port through the rotating paddle wheel.
Since the digestion reaction is a strong chemical reaction, the temperature inside the digester is above ℃, so the amount of water added should exceed the amount of water required for the digestion reaction. The excess water will all turn into water vapor and be discharged. Generally, the weight ratio of water to quicklime is: around.
<.Main parameters affecting digestion reaction< Digestion reaction equation
The reaction of quicklime and water to produce hydrated lime is generally called digestion reaction. The chemical reaction equation is as follows
< :\r\~\ \\\\ >< :\r\~\\\\\ >+()+.> molar weight+
Therefore, adding unit mass of pure calcium oxide and unit mass of water obtain unit mass of of calcium hydroxide.
This means that by adding unit mass of calcium oxide, units of slaked lime can be obtained. Therefore, the weight ratio of digested water to product is .%< :\r\~\\\\\ >.
It can be seen from the chemical reaction equation that this reaction is a strongly exothermic reaction. Each kilogram of calcium oxide digested will release heat.
The main reason why quicklime absorbs water and expands is the disintegration of solid and the increase in pore volume. At the same time, the specific surface area of particles increases, surface attachments increase, and the volume of solid particles also increases. It can also be seen from the chemical reaction formula +rr()+.kcal mol that when hydrated and digested into (), the theoretical volume increases by about .
The digestion of quicklime has been analyzed experimentally. The digestion period is divided into stages: Stage I, the inert period, in which the reaction of quicklime with water is not obvious. However, under the action of load, the sample still has a little consolidation; Stage II, the acceleration period. In the third stage, quicklime accelerates hydration and releases a large amount of digestion heat, and the volume of quicklime expands rapidly. Stage III is the stable period. In this stage, the volume of quicklime continues to expand slowly and eventually becomes stable. Among them, in stages II and III, the digestion of quicklime can absorb water. In some special cases, the digested oxide is not pure calcium oxide but the oxide generated by the calcination of dolomite or impure limestone. In this case, the amount of water added and the amount of heat emitted vary greatly due to changes in the impurities and contents inside.
..Reaction speed
Generally the reaction speed is mainly affected by the following factors:
Reaction temperature
Chemical composition of quicklime
Limestone calcination method
Particle size of quicklime
Stirring system.
Reaction temperature
The temperature of water and quicklime will affect the speed of digestion reaction. Generally, the speed of digestion reaction increases with the increase of reaction temperature. The relationship is as follows
() ().
() The reaction rate when the temperature is The higher the purity of quicklime, the less likely it is that the pores of quicklime will be clogged, and the chance that the surface of quicklime will be coated with impurity slag that melts during calcination, such as quartz, alumina, iron powder, etc., will also reduce. These impurities will hinder the contact between water and quicklime. In addition, the high magnesium oxide content present in quicklime powder will also have a negative impact on the reaction because higher magnesium content tends to cause overburning of the lime.
Activity of quicklime
The activity of quicklime depends on the particle size of quicklime and magnesium oxide crystals, the surface area ratio of quicklime powder after calcining the limestone and the porosity of the oxide.
These three characteristics are closely related. That is to say, the smaller the quicklime crystal particles, the greater the surface area ratio of quicklime and the higher the porosity. The realization of these properties depends largely on the calcination temperature and the residence time of quicklime in the kiln. The higher the calcining temperature, the longer the residence time of quicklime in the kiln, and the slower the digestion reaction of quicklime will be.
The conversion of calcium oxide into calcium hydroxide is a liquid reaction. When + and + ions form supersaturation in the solution, calcium hydroxide precipitates in crystalline form.
Due to the large surface area ratio and high porosity of the quicklime generated by light burning, the solution concentration can increase quickly during the reaction, and the supersaturated state is quickly reached. The strong supersaturation state during the crystallization process will inevitably lead to the rapid formation of single crystals.
On the contrary, if the digested quicklime is overburned quicklime, the solution concentration will increase slowly, the supersaturated crystallization precipitation rate will also be doubled, and the coarse-grained crystal formation rate will increase, and only coarse-grained slaked lime can be obtained.
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