CN102616818A - Low-temperature activation method of fly ash and application thereof - Google Patents

Abstract

The invention discloses an activation method of fly ash. The method comprises the steps of adding a certain amount of Na2CO3 and NaOH mixed assistants into fly ash, calcining the mixed assistants and the fly ash at a certain temperature and then performing sharp quenching on the mixed assistants and the fly ash, so as to obtain fly ash sintered clinker with high reaction activity, and then ensuring that the fly ash sintered clinker is reacted in hydrochloric acid solution with the mass concentration being 15 to 25 percent at 80 to 120 DEG C for 1 to 3 h to exact aluminum oxide. By adopting the method, fly ash is activated under the low-temperature condition of 600 to 750 DEG C, so that the dissolution rate of aluminum oxide can reach more than 90 percent.

Description

A kind of low-temperature activation method and application thereof of flyash

Technical field

The present invention relates to the comprehensive utilization of flyash, specifically is a kind of method of activating fly ash at low temperature, and the application of this method in the alumina extraction process.

Background technology

China is coal-fired big country, in the coal burning process, has produced a large amount of flyash.2010, the generation of China's flyash reached 4.8 hundred million tons, comprehensive utilization ratio 68%, and limited because of utilization ratio, the flyash of annual discharging still has more than 100,000,000 ton, has become one of maximum industrial solid castoff of China's quantity discharged.At present, China has stored up nearly 3,000,000,000 tons of flyash, has brought havoc to ecology.The utilization of coal ash approach mainly is to be used to build worker, building materials etc. at present, utilizes approach single, and utilization is limited, and opening up the new mode of utilizing is the fundamental way that its resource utilization of raising, minimizing are stored up.

Flyash contains and enriches aluminum oxide, alumina content about 30%.And China consumes big country as bauxite resource, the bauxite resource critical shortage, and China was from 44,850,000 tons of bauxite of external import in 2011.From flyash, extract aluminum oxide and prepare various aluminum products, not only can alleviate the situation of China's bauxite resource critical shortage, the resource utilization that improves flyash is also had very important meaning.

The process for extracting of aluminum oxide mainly contains Bayer process, soda-lime sintering process and acid system; Bayer process and soda-lime sintering process generally are applicable to the mineral of alumina silica ratio (mass ratio, down together) greater than 3, because alumina silica ratio is generally less than 1 in the flyash; See from the angle of economy and energy consumption; The general main acid system that utilizes promptly utilizes hydrochloric acid or sulfuric acid that the alumina dissolution in the flyash is formed water miscible aluminum salt solution, further again trans-utilization.Yet flyash mainly exists with Vitrea forms of ferro-silicon-aluminium such as mullite, melilith, sodalite and spinel ferrites, and structure is highly stable, and the non-constant of reactive behavior must be through overactivation ability and acid-respons.The activation of flyash mainly contains mechanical activation and thermal activation.Compare with mechanical activation, thermal activation is simple to operate, and activation effect is good and become a kind of method commonly used." flyash activating extracts the research of ferro-aluminum " (document 1) that Wang Miao etc. deliver in " scientific and technical innovation and yield-power " (2012 the 1st phase 92 pages), with flyash 500 ~ 900 ^oAfter the C calcining, use 20% hydrochloric acid then 100 ^oC leaching aluminum oxide wherein, the solubility rate of aluminum oxide only about 5%." a kind of method of alumina of from flyash, extracting " (number of patent application 200510048274.9) (document 2) of marriage between two families state, Zhai Yuchun research and development with flyash 300 ~ 760 ^oAfter the C roasting, the H with 60% ~ 98% ₂SO ₄160 ~ 330 ^oAluminum oxide in the C lixiviate flyash, the residue after the filtration is again 65 ~ 90 ^oC dissolves with poach, and the solubility rate of aluminum oxide reaches more than 85%.Can find out from document, adopt the method for thermal activation separately, the solubility rate of aluminum oxide very low (like document 1) have only the high acid concentration (like document 2) of employing could improve alumina extraction ratio, but sour consumption is big, and the acid concentration height also brings difficulty to operation.

When being employed in thermal activation, Many researchers improves the activation efficiency of flyash and the solubility rate of aluminum oxide through adding auxiliary agent." a kind of method of alumina of from flyash, extracting " (number of patent application 201110002303.3) (document 3) of people such as Pan Aifang exploitation with flyash and yellow soda ash mixed grinding after, through 620 ~ 990 ^oAfter the C roasting, the filtrate cycle leaching roasting grog after water and the leaching, the solubility rate of aluminum oxide only reaches about 75%." from flyash, extracting the method for high-purity ultra-fine alumina " (number of patent application 200710150915.0) (document 4) of invention such as Ji Huiming, Xu Mingxia mixes the back 850 ~ 950 with flyash with yellow soda ash ^oAfter the C calcining, with the dilute sulphuric acid of 1mol/L 70 ^oC leaches aluminum oxide, and digesting efficiency of alumina reaches more than 95%." utilizing aluminous fly-ash to produce aluminum oxide and WHITE CARBON BLACK process for cleanly preparing " (number of patent application 200710087028.3) (document 5) that horse great writing, poplar wait quietly inventing mixes the back 750 ~ 880 with flyash with yellow soda ash ^oAfter the C calcining, the sulfuric acid with 45 ~ 50% is 70 ^oC acidleach, ageing, the extraction rate reached 95% of aluminum oxide.Qiao Xiuchen, " a kind of method of activating fly ash at low temperature and application thereof " (number of patent application 200910055013.8) (document 6) of inventing in founding the state are employed in the flyash and increase the calcium auxiliary agent by calcium aluminum ratio 0.5 ~ 0.7:1, in 800 ~ 950 ^oAfter the C calcining, use dilute sulfuric acid, the leaching yield of aluminum oxide reaches more than 75%.Contrast above document, in thermal activation, add the auxiliary agent activation, though the extraction yield of aluminum oxide increases, calcining temperature is generally than higher.Thereby but the technology of developing a kind of low-temperature activation and ability high efficiency extraction aluminum oxide is very important.

Summary of the invention

But the object of the present invention is to provide a kind of method of activating fly ash at low temperature, and the application of this method in the alumina extraction process.

The method of a kind of activating fly ash at low temperature provided by the invention, concrete steps are:

Flyash and mixed aid are pressed mass ratio 1:0.6-1 uniform mixing, in 600 ^oC-750 ^oC calcining 1-3 h, chilling makes sintered clinker; Described mixed aid is Na ₂CO ₃Press mass ratio 1:0.3-4 preparation with NaOH; Calcining temperature preferred 650 ^oC-750 ^oC.

The application of the method for a kind of activating fly ash at low temperature provided by the invention in the alumina extraction process, concrete steps are:

1) flyash and mixed aid are pressed mass ratio 1:0.6-1 uniform mixing, in 600 ^oC-750 ^oC calcining 1-3 h, chilling makes sintered clinker; Described mixed aid is Na ₂CO ₃Press mass ratio 1:0.3-4 preparation with NaOH; Calcining temperature preferred 650 ^oC-750 ^oC;

2) sintered clinker is mixed according to mass ratio 1:3 ~ 6 with the hydrochloric acid of 15-25%, 80 ~ 120 ^oC reacts 2 h, and the stripping reactant removes by filter residue, obtains containing AlCl ₃Aluminum salt solution.

Through detecting, the solubility rate of aluminum oxide reaches more than 90%.

Advantage compared with prior art of the present invention and effect:

The present invention has broken through the technical bottleneck that existing flyash activating technology activation temperature is high, digesting efficiency of alumina is low, adopts new activating technology, at low temperature 600 ~ 750 ^oUnder the condition of C, the solubility rate of aluminum oxide can reach more than 90%.

Embodiment

Embodiment 1

1) flyash activating: get alumina content and be 35.3% flyash 100 g, add 20 g NaOH and 60 g Na ₂CO ₃, stir, in 650 ^oC calcines 3 h, and chilling makes sintered clinker;

2) aluminium is carried in acidleach: hydrochloric acid 750 mL of adding 18% in sintered clinker are warming up to 100 ^oC reacts 2 h, and the stripping reactant removes by filter residue, obtains AlCl ₃Aluminum salt solution.

Through adopting EDTA complexing-mantoquita residual titration method to detect the aluminium in the solution, the solubility rate that draws aluminum oxide is 92.1%.

Embodiment 2

1) flyash activating: get alumina content and be 35.3% flyash 100 g, add 50 g NaOH and 50 g Na ₂CO ₃, stir, in 700 ^oC calcines 2 h, and chilling makes sintered clinker;

2) aluminium is carried in acidleach: hydrochloric acid 900 mL of adding 20% in sintered clinker are warming up to 105 ^oC reacts 2 h, and the stripping reactant removes by filter residue, obtains AlCl ₃Aluminum salt solution.

After testing, the dissolution rate of aluminium oxide is 96.5%.

Embodiment 3

1) flyash activating: get alumina content and be 35.3% flyash 100 g, add 40 g NaOH and 30 g Na ₂CO ₃, stir, in 750 ^oC calcines 1 h, and chilling makes sintered clinker;

2) aluminium is carried in acidleach: hydrochloric acid 600 mL of adding 20% in sintered clinker are warming up to 95 ^oC reacts 2 h, and the stripping reactant removes by filter residue, obtains AlCl ₃Aluminum salt solution.

After testing, the dissolution rate of aluminium oxide is 95.3%.

Claims (4)

1. the method for an activating fly ash at low temperature is characterized in that step is:

Flyash and mixed aid are pressed mass ratio 1:0.6-1 uniform mixing, in 600 ^oC-750 ^oC calcining 1-3 h, chilling makes sintered clinker; Described mixed aid is Na ₂CO ₃Press mass ratio 1:0.3-4 preparation with NaOH.

2. the method for a kind of activating fly ash at low temperature as claimed in claim 1 is characterized in that, said incinerating temperature is 650 ^oC-750 ^oC.

3. the application of the method for an activating fly ash at low temperature in the alumina extraction process is characterized in that step is:

1) flyash and mixed aid are pressed mass ratio 1:0.6-1 uniform mixing, in 600 ^oC-750 ^oC calcining 1-3 h, chilling makes sintered clinker; Described mixed aid is Na ₂CO ₃Press mass ratio 1:0.3-4 preparation with NaOH;

2) sintered clinker is mixed according to mass ratio 1:3 ~ 6 with the hydrochloric acid of 15-25%, 80 ~ 120 ^oC reacts 2 h, and the stripping reactant removes by filter residue, obtains containing AlCl ₃Aluminum salt solution.

4. the application of the method for a kind of activating fly ash at low temperature as claimed in claim 3 in the alumina extraction process is characterized in that, said incinerating temperature is 650 ^oC-750 ^oC.