CN105621429A - Fly ash pressurized alkali-dissolution desilication treatment method - Google Patents

Abstract

The invention discloses a fly ash pressurized alkali-dissolution desilication treatment method which is characterized by comprising the following steps: drying fly ash in a drying oven, cooling, screening, and taking the fly ash with a certain particle size; preparing a NaOH solution with a certain concentration; adding a certain amount of the fly ash into the NaOH solution to prepare a reaction solution with a certain solid-to-liquid ratio, and uniformly mixing with a magnetic stirrer; adding the mixed solution into a high-pressure reaction kettle, and carrying out desilication reaction at a certain temperature; and after the reaction finishes, cooling to room temperature, and carrying out solid-liquid separation by high-speed centrifugation, thereby obtaining desilication slag and a sodium silicate solution. The method is scientific and reasonable, is simple and easy to implement, has the characteristics of low production cost, high desilication efficiency and the like, and has favorable application prospects for industrialized large-scale production.

Description

The treatment process of a kind of flyash pressurization alkali-soluble desiliconization

Technical field

The invention belongs to total utilization of PCA field, the treatment process of alkali-soluble desiliconization of pressurizeing in particular to a kind of flyash.

Background technology

Flyash is a kind of solid waste that coal firing boiler produces. It forms primarily of the char particle of sial glass, crystallite mineral grain and non-after-flame. The stacking mode not only land occupation resource that flyash is outdoor, but also cause the severe contamination of air, peripheral ground water source or underground water. Therefore, more and more in recent years people start to pay close attention to process and the cycling and reutilization of flyash. At present, the recycling of flyash mainly contains two aspects, and one is utilize for making the low big ash quantity of the added values such as cement, concrete, solidification of waste and structure filling thing; Two it is for reclaiming useful metal, prepares zeolite and mullite, further utilization as high added values such as refuse sorbing materials. Wherein because flyash is rich in Silicified breccias element, therefore how from flyash, effectively to extract one of Silicified breccias resource main research focus having become total utilization of PCA.

Flyash is the product that coal is formed after high-temp combustion, generally containing the amorphous Si O that the activity dissolving in NaOH solution is higher₂. Therefore, alkali-soluble process not only can realize selective extraction and the utilization of silicon resource, it is also possible to effectively reduces the growing amount of silicon calcium slag in subsequent oxidation aluminium leaching process. " mineral journal " (2007,27(2): the 137-142 sponsored by geochemical investigation institute of the Chinese Academy of Sciences, mineral rocks geonomy association of China) disclose the people such as Zhang Zhanjun and " from aluminous fly-ash, extract amorphous Si O₂Experimental study " one literary composition, literary composition in report the chemistry according to aluminous fly-ash and thing phase compositing characteristic, establish utilize NaOH extraction amorphous Si O₂Basic line, and by optimization of orthogonal test alkali-soluble technique. Result of study shows: after top condition is reacted, SiO₂Extraction rate reached 41.8%. The process engineering journal (2011 that Chinese Academy Of Sciences Process Engineering Research Institute sponsors, scientific publication society publishes, 11(3): 442-447) disclose people's " aluminous fly-ash alkali-soluble desiliconization process reaction mechanism " literary compositions such as Du Zichuan, literary composition reports and adopts multiple detection technique to analyze essential mineral composition and content in aluminous fly-ash, and in conjunction with thermodynamic stability analysis, investigated reaction times, temperature of reaction to the impact of the flyash thing phase before and after alkali-soluble desilication reaction, shape looks and surface chemistry composition. Result shows: amorphous Si O in aluminous fly-ash₂Account for total SiO₂More than half, adopt alkali-soluble desiliconization to be conducive to extracting amorphous SiO₂, but the impact of temperature of reaction is relatively big, 130 DEG C, reaction 2h when, SiO₂Solubility rate reaches 42.5%. By open source literature it will be seen that existing alkali solution technique extracts SiO₂Efficiency is general lower, the enforcement of the operations such as subsequent extracted aluminum oxide can be produced certain influence.

Summary of the invention

Technical problem to be solved by this invention is to provide a kind of scientific and reasonable, simple, and cost is low, desilication efficiency height, has the treatment process of the flyash pressurization alkali-soluble desiliconization of good industrialization large-scale production and application prospect.

The technical scheme solving the employing of its technical problem is, the treatment process of a kind of flyash pressurization alkali-soluble desiliconization, is characterized in that, it comprises the following steps:

(1) flyash being placed in baking oven, drying temperature is 105-120 DEG C, and time of drying is 10-12h, after dry, through cooling screening, obtains>0-<300 object flyash;

(2) compound concentration is the NaOH solution of 180-240g/L;

(3) flyash step (1) obtained and the NaOH solution of step (2), be 1:2-4 by solid-to-liquid ratio, flyash be placed in NaOH solution, mix with magnetic stirring apparatus, and preparation obtains mixed solution;

(4) joining in autoclave by mixed solution, temperature of reaction is 100-120 DEG C, and the reaction times is that 1-2h carries out desilication reaction;

(5) by the mixed solution of step (4) desilication reaction, it is cooled to room temperature, adopts supercentrifuge 3500-6000rpm to carry out solid-liquid separation, obtain desiliconization slag and sodium silicate solution.

The profitable fruit of the treatment process of flyash of the present invention pressurization alkali-soluble desiliconization is embodied in:

1) adopting taking flyash is reaction raw materials, and to pressurize, alkali-soluble mode carries out desiliconization process, and pressure treatment can contribute to promoting amorphous Si O₂Dissolving in alkali lye, thus be conducive to improving desiliconization rate, obtain the raw material of lime-ash for subsequent extracted aluminum oxide of high aluminium/silicon ratio;

2) by the silicon resource in pressurization alkali-soluble extract powder coal ash, its methodological science is reasonable, and simple, cost is low, and desiliconization rate height, is suitable for industrialization scale operation.

Embodiment

Below in conjunction with specific embodiment, set forth the present invention further. Limit the scope of the invention it will be understood that these embodiments are only not used in for illustration of the present invention. In addition it will be understood that after the content having read the present invention, the present invention can be made various change or amendment by those skilled in the art, and these equivalent form of values fall within the protection domain that the application's claim book limits equally.

The treatment process of a kind of flyash pressurization alkali-soluble desiliconization of embodiment 1, concrete steps are:

(1) flyash is placed in baking oven, through 120 DEG C of dry 10h, takes out dry flyash, then through cooling screening, obtain 0-< 200 object flyash;

(2) compound concentration is the NaOH solution of 220g/L;

(3) it is 1:4 according to the solid-to-liquid ratio of flyash and NaOH, the flyash that step (1) obtains is joined in the NaOH solution of step (2), and use magnetic stirrer 20min, obtain mixed solution;

(4) mixed solution that step (3) obtains is joined in autoclave, react 2h through 120 DEG C and carry out desiliconization;

(5) after question response terminates to be cooled to room temperature, the mixed solution of step (4) desilication reaction is cooled to room temperature, adopts supercentrifuge 3500-6000rpm to carry out solid-liquid separation, obtain desiliconization slag and sodium silicate solution.

The treatment process of a kind of flyash pressurization alkali-soluble desiliconization of embodiment 2, concrete steps are:

After (1) flyash is placed in baking oven 110 DEG C of dry 10h, takes out dry flyash, then through cooling screening, obtain 0-< 250 object flyash;

(2) compound concentration is the NaOH solution of 200g/L;

(3) it is 1:3 according to the solid-to-liquid ratio of flyash and NaOH, the flyash that step (1) obtains is joined in the NaOH solution of step (2), and use magnetic stirrer 20min, obtain mixed solution;

(4) mixed solution that step (3) obtains is joined in autoclave, react 2h through 110 DEG C and carry out desiliconization;

(5) after question response terminates to be cooled to room temperature, the mixed solution of step (4) desilication reaction is cooled to room temperature, adopts supercentrifuge 3500-6000rpm to carry out solid-liquid separation, obtain desiliconization slag and sodium silicate solution.

The treatment process of a kind of flyash pressurization alkali-soluble desiliconization of embodiment 3, concrete steps are:

After (1) flyash is placed in baking oven 105 DEG C of dry 12h, takes out dry flyash, then through cooling screening, obtain 0-< 300 object flyash;

(2) compound concentration is the NaOH solution of 180g/L;

(3) it is 1:2 according to the solid-to-liquid ratio of flyash and NaOH, the flyash that step (1) obtains is joined in NaOH solution, and uses magnetic stirrer 20min;

(4) mixed solution that step (3) obtains is joined in autoclave, 100 DEG C of reaction 1h;

(5) after question response terminates to be cooled to room temperature, the mixed solution of step (4) desilication reaction is cooled to room temperature, adopts supercentrifuge 3500-6000rpm to carry out solid-liquid separation, obtain desiliconization slag and sodium silicate solution.

The raw material realizing the present invention used is easy to get, and is commercially available prod, and equipment used is the commercially available prod of prior art, it is easy to implement.

Claims (1)

1. a treatment process for flyash pressurization alkali-soluble desiliconization, is characterized in that, it comprises the following steps:

(1) flyash being placed in baking oven, drying temperature is 105-120 DEG C, and time of drying is 10-12h, after dry, through cooling screening, obtains>0-<300 object flyash;

(2) compound concentration is the NaOH solution of 180-240g/L;

(3) flyash step (1) obtained and the NaOH solution of step (2), be 1:2-4 by solid-to-liquid ratio, flyash be placed in NaOH solution, mix with magnetic stirring apparatus, and preparation obtains mixed solution;

(4) joining in autoclave by mixed solution, temperature of reaction is 100-120 DEG C, and the reaction times is that 1-2h carries out desilication reaction;

(5) by the mixed solution of step (4) desilication reaction, it is cooled to room temperature, adopts supercentrifuge 3500-6000rpm to carry out solid-liquid separation, obtain desiliconization slag and sodium silicate solution.