Method for treating calcium in high-calcium fly ash

A high-calcium fly ash and treatment method technology, applied in the direction of calcium/strontium/barium halide, calcium/strontium/barium chloride, calcium/strontium/barium nitrate, etc., can solve the problem of rising acid and alkali consumption, high Problems such as the limitation of comprehensive utilization of calcium fly ash and the increase of secondary residues have achieved the effect of improving economic benefits

Active Publication Date: 2015-09-02
河南省睿博环境工程技术有限公司
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  • Claims
  • Application Information

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Problems solved by technology

In the production of alumina and white carbon black by the above process, too high calcium oxide content is harmful, it will not only cause a substantial increase in acid and alkali consumption during the treatment process, but also lead to an increase in the amount of secondary residues
At present, due to the inability to solve the problem of calcium removal in high-calcium fly ash, the comprehensive utilization of high-calcium fly ash is limited

Method used

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  • Method for treating calcium in high-calcium fly ash

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Embodiment 1

[0049] Source and composition of fly ash: Henan Tongbai fly ash, CaO 28.38%; Al 2 o 313.19%; SiO 2 44.22%; SO 4 2- 4.48%; MgO 1.68%; Fe 2 o 3 4.26%.

[0050] Weigh 1000g of fly ash into a beaker, add 3000ml of water and stir to form a slurry, then add 185g of ammonium bicarbonate, stir and react for 2 hours at room temperature, filter, add appropriate amount of water to wash. Reaction received 1800g filter cake, containing SO 4 2- 3.80g, the conversion rate of calcium sulfate is 91.52%.

[0051] Add 1800g of filter cake to 500ml of water and stir to form a slurry, add 666ml of 65% nitric acid at room temperature, keep the reaction at 65°C for 1h, filter and wash, and obtain 1800ml of calcium nitrate solution, containing Ca(NO 3 ) 2 788g, 900g filter cake after decalcification, containing 1.63% CaO, 14.67g combined CaO, calcium removal rate 94.83%.

[0052] Heat and evaporate 1800ml of calcium nitrate solution with 32Be' to 55 Be', cool and add 30g of calcium nit...

Embodiment 2

[0056] Source and composition of fly ash: fly ash from Henan Xinxiang Xinlianxin Fertilizer Co., Ltd., CaO 33.53%; Al 2 o 3 17.05%; SiO 2 32.89%; SO 4 2- 8.53%; MgO 2.00%; Fe 2 o 3 3.29%.

[0057] Weigh 100kg of fly ash into a beaker, add 200L of water and stir to form a slurry, then add 9.81kg of sodium carbonate, stir and react at 80°C for 2h, then filter, add appropriate amount of water to wash. Reaction received 170kg filter cake, containing SO 4 2- 0.85kg, the conversion rate of calcium sulfate is 90.04%.

[0058] Add 170kg of filter cake to 80L of water and stir to form a slurry, add 96L of 36% hydrochloric acid at room temperature, keep it at 95°C for 1 hour, filter and wash to obtain 247L of calcium chloride solution, containing CaCl 2 62kg, 85kg filter cake after decalcification, containing 2.65% CaO, 2.25kg combined CaO, 93.29% calcium removal rate

[0059] Calcium chloride solution 247L, containing CaCl 2 62kg, the calcium chloride concentration is ...

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Abstract

The invention discloses a method for treating calcium in high-calcium fly ash, which comprises the steps of phase inversion reaction, decalcification reaction and calcium compound preparation. The technique principle comprises the following steps: converting calcium sulfate in fly ash into calcium compounds capable of reacting with hydrochloric acid and nitric acid by a phase inversion process, treating the fly ash with hydrochloric acid or nitric acid to convert the calcium compounds in the fly ash into soluble calcium chloride or calcium nitrate, and separating to collect a calcium chloride or calcium nitrate solution and a decalcified fly ash filter cake; and concentrating the calcium chloride or calcium nitrate solution, and crystallizing to collect the calcium chloride or calcium nitrate product. The decalcified fly ash filter cake is sent to a subsequent procedure and subjected to acid hydrolysis and alkaline hydrolysis, the acid leach solution is used for preparing aluminum ammonium sulfate, aluminum oxide, cryolite, aluminum fluoride, high-purity iron oxide or iron oxide red, the water glass is used for preparing silica white other silicon compounds, and the decomposition residues are mixed with coal to be used as a boiler fuel.

Description

technical field [0001] The invention belongs to the technical field of fly ash treatment, and in particular relates to a method for treating calcium in high-calcium fly ash. Background technique [0002] The utilization methods of fly ash that have been reported are: used as raw material for producing cement, used for producing aerated concrete, used for producing other wall materials, used for making chemical fertilizer, etc., and the utilization level is low. In recent years, the extraction of alumina and white carbon black from fly ash has been a hot spot of research and attention. The reported processes include limestone roasting, soda lime roasting, sodium carbonate roasting, pre-desilicate soda lime roasting, Ammonium sulfate roasting method, acid method, acid-base combination method, etc. The prepared products are metallurgical grade alumina and precipitated silica. [0003] In addition to silicon, aluminum and iron elements, fly ash also contains a certain amount o...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01F11/38C01F11/24
Inventor 肖景波陈居玲夏娇彬张生
Owner 河南省睿博环境工程技术有限公司
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