Preparation method of high-purity fine calcium carbonate
A fine calcium carbonate, high-purity technology, applied in calcium carbonate/strontium/barium, chemical instruments and methods, calcium/strontium/barium compounds, etc., can solve the problems of food visual effects not meeting the requirements and dark colors, etc. Achieve the effect of simple preparation method, small particles and low operation cost
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[0023] A preparation method of high-purity fine calcium carbonate, comprising the following steps:
[0024] Step 1) Calcining limestone at 850°C-1200°C to generate calcium oxide;
[0025] Step 2) add water to digest the lime to generate milk of lime;
[0026] Step 3) Remove impurities from the milk of lime obtained in step 2 with a 100-300 mesh screen, and pass through a hydrocyclone to obtain fine calcium hydroxide;
[0027] Step 4) Pass the purified kiln gas into the calcium hydroxide at a rate of 3-10 liters / minute at 28°C-40°C, the content of carbon dioxide in the purified kiln gas is between 30%-36%, and react for 5-8h , when the pH value of the milk of lime suspension continuously drops to 6.8-7.2, the carbonization reaction is terminated and a white water slurry is obtained;
[0028] Step 5) The white water slurry is naturally precipitated, dehydrated by filtering equipment, dried at 100°C-115°C for 0.5-1h, and then dry-grinded and dispersed at a grinding rate of ...
Embodiment 1
[0031] Take 200kg of limestone and calcinate at 850°C to produce 80kg of calcium oxide, use a 100-mesh screen to remove impurities, use a hydrocyclone to separate 42kg of fine calcium oxide, add 130kg of water to the calcium oxide for digestion, and generate 40kg of calcium oxide Lime milk, feed the purified kiln gas into the lime milk at a rate of 3 liters / min, the content of carbon dioxide in the purified kiln gas is 30%, and the pH value of the lime milk reaches 6.8 after 5 reactions to generate a white water slurry, and the white water slurry Natural precipitation, dehydration by filtration equipment, drying treatment at 100°C for 0.5h, and then dry grinding to disperse at a grinding rate of 1300r / min, and 20kg of fine-grained calcium carbonate was obtained after sieving.
Embodiment 2
[0033] Take 200kg of limestone and calcinate at 1000°C to produce 90kg of calcium oxide, use a 200-mesh screen to remove impurities, use a hydrocyclone to separate 50kg of fine calcium oxide, add 150kg of water to the calcium oxide for digestion, and generate 50kg of calcium oxide Lime milk, pass into the purified kiln gas with a rate of 6 liters / min in the lime milk, the content of carbon dioxide in the purified kiln gas is 34%, the pH value of the lime milk reaches 7 after reacting for 5 hours, and generates white water slurry, the white water The slurry was naturally precipitated, dehydrated by filtering equipment, dried at 110°C for 0.7h, and then dry-grinded and dispersed at a grinding rate of 1400r / min. After sieving, 30kg of fine-grained calcium carbonate was obtained.
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