CN105271313A - Novel method for comprehensively utilizing potassium feldspar - Google Patents

Abstract

The invention discloses a new method for comprehensive utilization of potassium feldspar, which uses _NaOH - _Na2CO3 mixed sub-molten salt to decompose potassium feldspar to obtain potassium feldspar decomposition mother liquor and cancryptite. Potassium feldspar decomposition mother liquor is carbonated, filtered to obtain potassium bicarbonate filtrate and silica-alumina filter residue, and the filtrate is evaporated, crystallized and dried to obtain potassium carbonate; at the same time, the silica-alumina filter residue is obtained by adding KOH, Al(OH ) ₃ and H ₂ O, adjusting the ratio of K ₂ O/SiO ₂ , Al ₂ O ₃ /SiO ₂ and H ₂ O/SiO ₂ in the system, aging and crystallizing at a certain temperature for a period of time to synthesize W molecular sieve. This method has the characteristics of low decomposition temperature, high potassium ion dissolution rate, easy acidification of the decomposition mother liquor, high added value of products, high utilization rate of raw materials, and no waste liquid and residue generation. It conforms to the principle of green production and has good potential economic benefits.

Description

A New Method of Comprehensive Utilization of Potassium Feldspar

technical field

The invention belongs to the technical field of mineral resource processing, preparation of inorganic metal compounds and aluminosilicate compound preparation technology, and specifically relates to the utilization of potassium feldspar and the preparation of potassium carbonate, cancryptite and W molecular sieve.

Background technique

my country's soluble potassium resources are poor, accounting for only about 0.4% of the world's total reserves. With the steady improvement of economic development, the country's demand for water-soluble potassium salts is increasing year by year, and the production capacity and demand are far apart. my country is rich in non-water-soluble potassium resources, among which potassium feldspar mines are widely distributed in 23 provinces and regions, and the proven reserves reach tens of billions of tons.

Potassium feldspar (KAlSi ₃ O ₈ ) theoretically contains 16.9% of K ₂ O, 64.7% of SiO ₂ and 18.4% of Al ₂ O ₃ . Potassium, silicon and aluminum resources. In view of the potassium resources contained in potassium feldspar, water-soluble potassium salt can be produced through deep processing of potassium feldspar, and it is a research trend in recent years to make silicon and aluminum in potassium feldspar into high value-added molecular sieves.

The methods for preparing potassium salt by decomposition of potassium feldspar can be roughly divided into the following categories: limestone roasting method, medium temperature decomposition method, high temperature alkali fusion method, sintering method, low temperature decomposition method, microbial method, etc. Among them, sintering method and low temperature decomposition method are two more commonly used methods. The sintering method mainly uses composite additives and potassium feldspar to calcine, which can reduce the reaction temperature to a certain extent, but the reaction still needs to be carried out in a reaction furnace at 600-850°C, which consumes a lot of energy. The low-temperature decomposition method mainly uses sulfuric acid and fluorine-containing additives to react with potassium feldspar at low temperature (90~150°C). This method is characterized by the comprehensive utilization of potassium feldspar, but the dissolution rate of potassium is low, and the residue will pollute the environment. Seriously, it is not conducive to the industrialization of production. Other methods have disadvantages such as high energy consumption, high cost, complicated process and many tailings residues in technology and economy. The sub-molten salt method proposed by Academician Zhang Yi (ZhangY, LiZH , QiT. Green Chemistry of Chromate Cleaner Production [J]. Chinese Journal of Chemistry . 1999, 17 (3): 258-266.) of the Process Institute of the Chinese Academy of Sciences has been successfully applied to the extraction of chromium, vanadium, and Insoluble minerals such as titanium and aluminum are characterized by low energy consumption at low temperature and high metal dissolution rate, which can exactly solve the above problems.

On the other hand, in the method for preparing molecular sieve by potassium feldspar reported at present, most adopt roasting method to decompose potassium feldspar, such as Du Cuihua etc. (Du Cuihua, Zhao Bin, Guo Hongfei etc.. W-type molecular sieve [J]. Acta Synthetic Crystal, 2014, 43(1): 1-10.) W molecular sieve was synthesized by KOH alkali fusion activation of potassium feldspar at 500°C; Zhang Jieqing et al. (Zhang Jieqing, Cao Jilin, Liu Xiuwu et al. Synthesis of 4A zeolite by alkali fusion activation of potassium feldspar[J]. Journal of Synthetic Crystallography, 2013, 42(5):953-958.) 4A molecular sieve was synthesized by roasting and decomposing potassium feldspar with Na ₂ CO ₃ at 780°C ; ZSM-5 molecular sieve[J]. Chinese Journal of Silicates, 2014,42(3):340-348.) and Li Xianzhou et al. ].World Geology, 2008,27( ₄ ):454-458.) Mesoporous silica-alumina molecular sieves, K _- ZSM-5 molecular sieves and mesoporous X type molecular sieve. Generally speaking, the above method has two disadvantages: first, the reaction temperature of roasting and decomposing potassium feldspar is above 500°C, and the energy consumption of the process is relatively large; second, the method reported above is mainly aimed at synthesizing molecular sieves, and the The requirement of potassium dissolution rate is not high, which causes waste of potassium resources to a certain extent.

Therefore, in order to solve the problems in the process of extracting potassium from potassium feldspar and preparing molecular sieve simultaneously, the present invention proposes to decompose potassium feldspar and synthesize cancryptite and W molecular sieve with NaOH-Na _{CO The} mixed sub-molten salt is the medium, and obtains in addition K ₂ CO ₃ , by-product Na ₂ CO ₃ , explores a new technological route for the comprehensive utilization of potassium feldspar. In addition to maintaining the advantages of low decomposition temperature and high metal dissolution rate of the sub-molten salt method, this scheme can also reduce the difficulty of subsequent acidification. The by-produced Na ₂ CO ₃ can be recycled, which improves the utilization rate of raw materials and has good potential economic benefits.

Contents of the invention

The purpose of the present invention is to utilize _NaOH - _Na2CO3 mixed sub-molten salt to decompose potassium feldspar, utilize the potassium, silicon, aluminum source contained in potassium feldspar to prepare potassium carbonate, cancryptite and W molecular sieve, realize potassium feldspar resource comprehensive utilization.

To achieve the above object, the present invention adopts the following technical solutions:

A kind of new method of comprehensive utilization of potassium feldspar of the present invention, comprises the steps:

(1) Mix potassium feldspar powder and NaOH-Na ₂ CO ₃ mixed sub-molten salt solution according to the ratio, put it into the polytetrafluoroethylene lining, and then put the polytetrafluoroethylene lining into the autoclave, and fixed in a homogeneous stirring reactor, heated to the decomposition temperature of potassium feldspar ore powder, and reacted for a period of time; the clinker after the reaction was filtered and washed, and the filter residue was dried to be cancryptite, and the filtrate was the decomposition of potassium feldspar Mother liquor;

(2) Introduce _CO2 into the potassium feldspar decomposition mother liquor for carbonation, and adjust the pH to 8~10, so that silicon and aluminum are precipitated to form a silicon-aluminum filter residue, and the filtrate is obtained by filtration and separation, and the filtrate is recycled to the Step (1) is used for the decomposition of potassium feldspar;

(3) After at least two cycles from step (1) to step (2), adjust the pH of the obtained potassium feldspar decomposition mother liquor to 5~8 to ensure that the sodium and potassium in the potassium feldspar decomposition mother liquor are converted to NaHCO ₃ and KHCO ₃ , then filter potassium feldspar to decompose the mother liquor to obtain the filtrate, and then filter and separate the obtained filtrate through at least three evaporations, crystallization and separation to obtain NaHCO ₃ and KHCO ₃ , and dry and decompose at 200°C to obtain Na ₂ CO ₃ and K ₂ CO ₃ , Na ₂ CO ₃ solids can be recycled for the decomposition of potassium feldspar in step (1);

(4) For the silica-alumina filter residue precipitated in step (2), adjust the system K ₂ O/SiO ₂ , Al ₂ O ₃ /SiO ₂ and H ₂ O by adding KOH, Al(OH) ₃ and H ₂ O / _SiO2 ratio, aging and crystallization at a certain temperature for a period of time, the product is filtered and washed, the filter cake is W molecular sieve, and the filtrate is W molecular sieve mother liquor, which can be recycled for the synthesis of W molecular sieve.

The concentration of the NaOH-Na ₂ CO ₃ mixed sub-molten salt solution in the step (1) is 50wt%-80wt%.

In the step (1), Na ₂ CO ₃ accounts for 30-50% of the total alkali content of the NaOH-Na ₂ CO ₃ mixed sub-molten salt.

In the step (1), the weight ratio of potassium feldspar ore to NaOH-Na ₂ CO ₃ mixed sub-molten salt is 1:3.0-6.0.

In the step (1), the decomposition temperature of the potassium feldspar is 190-210° C., and the decomposition time is 2-5 hours.

In the step (2), when the potassium feldspar decomposition mother liquor is passed into CO ₂ for carbonation, the SiO ₃ ^2- concentration in the potassium feldspar decomposition mother liquor is controlled to be 0.3~0.6mol/L, and the flow rate of CO ₂ is 0.2~0.4 L/min, mechanical stirring is used during the carbonation process, and the speed is 400~600r/min.

The W molecular sieve synthesis system material weight ratio in the step (4) is preferably K ₂ O/SiO ₂ =0.5~1.5, Al ₂ O ₃ /SiO ₂ =0.02~0.15, H ₂ O/SiO ₂ =35~55 .

The synthesis of W molecular sieves in the step (4) requires aging at 25-50°C for 2-5 hours, and crystallization at 140-170°C for 12-48 hours.

Specifically, the above-mentioned potassium feldspar used in the present invention is a potassium-containing aluminosilicate mineral with a stable silicon-aluminum and silicon-oxygen tetrahedral structure. Potassium feldspar ore usually starts to melt above 1150°C and completely melts near 1400°C. Therefore, in order to reduce energy consumption, the method of adding additives is generally used to decompose potassium feldspar, such as the commonly used alkali fusion method and sintering method. Taking potassium feldspar-sodium carbonate system as an example, the decomposition temperature of potassium feldspar can be reduced to 750~850℃. On the one hand, the addition of sodium carbonate to form a eutectic can reduce the melting temperature of the system. On the other hand, sodium carbonate participates in the reaction, that is, the solid phase decomposition reaction of potassium feldspar and sodium carbonate causes the stable silicon (aluminum) oxygen structure to be destroyed. Previously, we used sodium hydroxide sub-molten salt system to decompose potassium feldspar, which can be carried out at low temperature (below 200°C) and normal pressure. Alkali solution produces highly active oxygen anions and hydroxide ions in the sub-molten salt region, and O ^2- interaction occurs at the interface with the potassium feldspar lattice, resulting in lattice distortion. At the same time, as an unconventional medium between the aqueous solution and the molten salt, the sub-molten salt provides a good flow environment for the entire reaction, has a certain solubility for the reactants and products, and plays a good role in dispersing and transferring the reaction system. Increased reaction rate. In a good flow environment, the K ⁺ in the potassium feldspar lattice structure rapidly diffuses to the outside of the lattice, thereby decomposing the potassium feldspar ore to achieve the purpose of potassium extraction. However, sodium hydroxide sub-molten salt also has limitations, such as the high concentration of NaOH, the subsequent acidification process requires a large amount of acid and a long acidification time, NaOH cannot be recycled, and the economic cost is high; and the residue generated by the reaction is sodalite , very stable, difficult to use, resulting in a waste of resources. The present invention uses NaOH-Na ₂ CO ₃ mixed sub-molten salt system to decompose potassium feldspar, and replaces part of NaOH with Na ₂ CO ₃ , but still ensures that the whole reaction system has the characteristics of sub-molten salt medium. Since the introduction of Na ₂ CO ₃ does not reduce the total salt concentration, sodium hydroxide can still produce highly active oxygen anions O ^2- to interact with O ^2- in the potassium feldspar crystal lattice, and CO ₃ ^2- can also participate in the reaction, and the simultaneous action of the two causes the three-dimensional framework structure of potassium feldspar to be destroyed, and the decomposition of potassium feldspar is realized. Since the alkalinity of Na ₂ CO ₃ is weaker than that of NaOH, it is beneficial to reduce the total alkalinity of the reaction. At the same time, the Na ₂ CO ₃ produced in the process of carbonation and evaporative crystallization can be recycled as a raw material for the reaction, improving the economy of the entire production process benefit. Secondly, because the introduced new anion CO ₃ ^2- can participate in the reaction, the reaction residue is changed from sodalite (molecular formula Na ₈ Si ₆ Al ₆ O ₂₄ (OH) ₂ (H ₂ O) ₂ ) to cancryptite (molecular formula Na ₈ (Si6Al ₆ O ₂₄ )(H _0.88 (CO ₃ ) _1.44 )(H ₂ O) ₂ ). Cancryptite is a kind of aluminosilicate crystal with one-dimensional channels of twelve-membered rings, which exists in a small amount in nature. During the synthesis process of cancryptite, due to stacking faults, it will cause defects and block the pore channels of ions, which makes it different from ordinary molecular sieves, and basically does not have ion exchange capacity. However, this structure enables it to be used as the host material of the host-guest structure, and has applications in the one-dimensional directional growth of guest molecules. At the same time, due to the special structure of cancryptite, it can fix anion groups, unstable molecules and atomic groups with optical and electrical properties in their channels to meet the requirements of optical, electrical and other applications.

The research of the present invention shows that the total alkali concentration, the percentage of Na ₂ CO ₃ in the total alkali amount, the ratio of alkali ore, reaction temperature and reaction time have great influence on the decomposition of potash feldspar ore and the formation of cancryptite. In the present invention, the total alkali concentration is preferably 50-80wt% NaOH-Na ₂ CO ₃ mixed solution, and its concentration is the conventional concentration in the sub-molten salt field. When Na ₂ CO ₃ accounts for 30-50% of the total alkali content of the NaOH-Na ₂ CO ₃ mixed sub-molten salt, the reaction system has the characteristics of a sub-molten salt medium, the reaction activity is large, and the decomposition effect of potassium feldspar is good, and it can Ensure that the filter residue generated by the reaction is cancryptite. When the weight ratio of potassium feldspar ore and NaOH-Na ₂ CO ₃ mixed sub-molten salt is 1:3.0~6.0, the fluidity of the whole reaction system is good; when the weight ratio is lower than 1:3.0, the fluidity of the reaction system is poor, and the reaction medium and Potassium feldspar cannot be fully contacted, and the efficiency of the decomposition process is low; when the weight ratio is higher than 1:6.0, the dissolution rate of potassium ions is close to the limit, and the dissolution rate of potassium ions does not change much when the weight ratio continues to increase. The reaction temperature is preferably 190-210°C. When the reaction temperature rises, the viscosity of the sub-molten salt medium decreases and the fluidity increases, which increases the activity of the sub-molten salt medium, increases the active oxygen negative ions, and accelerates the decomposition of potassium feldspar; The temperature range is also suitable for the formation of cancryptite. When the reaction temperature is lower than 190°C, the decomposition effect of potassium feldspar is general, and at the same time, the filter residue of cancryptite contains more impurities; when the reaction temperature is higher than 210°C, the decomposition of potassium feldspar and cancryptite generation has almost no effect. The reaction time is preferably 2~5h, because the sub-molten salt needs to fully contact with potassium feldspar, gradually destroy the structure of potassium feldspar and dissolve potassium ions. Of course, potassium feldspar can also be decomposed when the reaction time is less than 2h, but The decomposition effect is not good; when the reaction time is 2~5h, not only the decomposition effect of potassium feldspar is significantly improved, but also relatively pure cancryptite can be produced.

In addition, the study also found that the pH value of the acidification of the potassium feldspar decomposition mother liquor is preferably 8-10. At this time, most of the silicon and aluminum in the decomposition mother liquor will exist in the form of precipitates. The concentration of SiO ₃ ^2- in the decomposition mother liquor is 0.3~0.6mol/L, the flow rate of CO ₂ is 0.2~0.4L/min, mechanical stirring is used in the acidification process, and the rotation speed is 400~600r/min. The filter residue is granular with uniform size and high reactivity, and is suitable as a silicon-aluminum source for synthesizing W molecular sieves. If the concentration of SiO ₃ ^2- in the decomposed mother liquor is too high, the flow rate of CO ₂ is too high, the number of revolutions is too low or magnetic stirring is used, the silicon-aluminum filter residue obtained at this time will be gelatinous, difficult to dry, and easy to produce hard agglomerations. Grinding and re-drying are still required to prepare molecular sieves, and the overall operation is relatively complicated.

At the same time, the study also found that in the process of preparing W molecular sieves, the system composition is required to be K ₂ O/SiO ₂ =0.5~1.5, Al ₂ O ₃ /SiO ₂ =0.02~0.15, H ₂ O/SiO ₂ =35~ 55, then aged at 25~50℃ for 2~5h, and crystallized at 140~170℃ for 12~48h. At this time, the synthesized W molecular sieve has the best performance. Due to its high potassium content, W molecular sieve has good selectivity to potassium ^ions . In addition to being directly applied as a slow-release potassium fertilizer, it can also be used to extract potassium from seawater. .

The beneficial effects of the present invention are reflected in:

1. Using cheap and easy-to-obtain potassium feldspar as raw material can make full use of potassium, silicon and aluminum resources in potassium feldspar, and avoid resource waste.

2. Potassium feldspar can be decomposed by using NaOH-Na ₂ CO ₃ mixed sub-molten salt at about 200°C, and the dissolution rate of potassium ions is as high as 98.96wt%. High, simple operation, and low requirements for equipment; at the same time, compared with other hydrothermal decomposition of potassium feldspar, the alkalinity of the entire reaction system is lower, which reduces the use of acidifiers and saves costs.

3. The filter residue generated after the decomposition of potassium feldspar is cancryptite, which has certain applications in the aspects of object molecules, light and electricity.

4. Using _CO2 as the acidifying agent for the mother liquor of potassium feldspar decomposition has the advantages of relatively simple process and easy recycling. After acidification, a mixed solution containing NaHCO ₃ and KHCO ₃ is obtained, evaporated and crystallized, NaHCO ₃ and KHCO ₃ are separated, and then dried and decomposed to obtain Na ₂ CO ₃ and K ₂ CO ₃ , realizing the conversion of insoluble potassium resources in potassium feldspar to soluble potassium resource shift. At the same time, the acidified filtrate can be recycled for the decomposition of potassium feldspar, which not only saves energy and reduces emissions, but also can increase the potassium content in the filtrate, and obtain more and purer K ₂ CO ₃ at one time, which has good potential economic benefits.

5. It is a research trend in recent years to use the silica-alumina filter residue obtained after the decomposition of potassium feldspar for the preparation of molecular sieves, and W molecular sieves can be used to extract potassium from seawater because of their good selectivity to potassium ions, and the potassium ion exchange capacity of seawater It is 50-60mgK ⁺ /g, which can further alleviate the shortage of soluble potassium resources in China. At the same time, it can also be directly applied as a slow-release potassium fertilizer, and the added value of the product is high.

6. The mother liquor after preparing W molecular sieve can be recycled by adding KOH, silica-alumina filter residue and Al(OH) ₃ to avoid discharge of waste liquid and waste residue.

Description of drawings

Fig. 1 is a process flow diagram of the present invention.

Fig. 2 is the XRD control spectrum of the filter residue cancryptite obtained from the decomposition of potassium feldspar ore in examples 1, 3, 5 and 6.

Fig. 3 is the SEM control spectrogram of the filter residue cancryptite obtained by the decomposition of potassium feldspar ore in examples 1, 3, 5 and 6.

Fig. 4 is the XRD control spectrum of the W molecular sieve prepared by using the silica-alumina filter residue in Examples 1, 10, 11, 12 and 16.

Fig. 5 is the SEM control spectrogram of the W molecular sieve prepared by using the silica-alumina filter residue in Examples 1, 10, 11, 12 and 16.

Fig. 6 is the XRD pattern of the silica-alumina filter residue obtained after the acidification of the potassium feldspar ore decomposition mother liquor in Example 1.

Fig. 7 is the SEM spectrogram of the silica-alumina filter residue obtained after acidifying the potassium feldspar ore decomposition mother liquor in Example 1.

Fig. 8 is the XRD comparison spectrum of the filter residue cancryptite obtained by decomposing potassium feldspar with different cycles of acidification mother liquor in Example 1.

Fig. 9 is a comparison spectrum of W molecular sieves synthesized before and after circulation of the W molecular sieve mother liquor in Example 1.

detailed description

As shown in Figure 1, the present invention discloses a new method for comprehensive utilization of potassium feldspar, using NaOH-Na ₂ CO ₃ mixed sub-molten salt to decompose potassium feldspar to obtain potassium feldspar decomposition mother liquor and cancryptite. Potassium feldspar decomposition mother liquor is carbonated, filtered to obtain potassium bicarbonate filtrate and silica-alumina filter residue, and the filtrate is evaporated, crystallized and dried to obtain potassium carbonate; at the same time, the silica-alumina filter residue is obtained by adding KOH, Al(OH ) ₃ and H ₂ O, adjusting the ratio of K ₂ O/SiO ₂ , Al ₂ O ₃ /SiO ₂ and H ₂ O/SiO ₂ in the system, aging and crystallizing at a certain temperature for a period of time to synthesize W molecular sieve.

Example 1

(1) Mix 7.50gNaOH and 7.50gNa ₂ CO ₃ with 15.00gH ₂ O and add to 100ml polytetrafluoroethylene lining, then add 10.00g K ₂ O content of 8.61% potassium long through 150 mesh sieve Stone ore powder, after stirring evenly, put it into the autoclave, and fix it in the homogeneous stirring reactor (HZ-6), raise the temperature of the reactor to 200°C, start timing, stop heating after 4 hours of reaction, and wait for the reactor to cool Finally, take out the inner liner, filter and wash the sample until the filter cake is free of CO ₃ ^2- , and then dry it at 105°C for 2 hours. The obtained filtrate is a potassium-containing filtrate, that is, the potassium feldspar decomposition mother liquor, and the dissolution rate of potassium ions in the potassium feldspar is measured to be 95.33wt%.

(2) Pass CO ₂ into the potassium-containing filtrate in step (1) for acidification, control the concentration of SiO ₃ ^2- in the filtrate to be about 0.5mol/L, and the flow rate of CO ₂ to be 0.3L/min. During the acidification process While stirring, the rotating speed is 500r/min. After 2 hours of reaction, the pH value of the solution was adjusted to 10, so that silicon and aluminum were precipitated. After filtration and separation, the filtrate contained a large amount of CO ₃ ^2- and HCO ₃ ^- . The filtrate was divided into two parts by volume, and each part was evaporated to volume When it is about 20ml, add 7.50g NaOH, evaporate to a volume of 20ml, and recycle to step (1) to decompose potassium feldspar respectively.

(3) After repeating the above steps (1) and (2) 4 times, acidify the finally obtained filtrate to pH = 8, and obtain NaHCO ₃ and KHCO ₃ through 4 times of evaporation, crystallization and separation, and dry at 200°C Decompose to get Na ₂ CO ₃ and K ₂ CO ₃ , Na ₂ CO ₃ solid can still be used for potassium feldspar decomposition.

(4) According to the molar ratio K ₂ O/SiO ₂ =1.0, Al ₂ O ₃ /SiO ₂ =0.067, H ₂ O/SiO ₂ =45, take 2.83g of the silica-alumina filter residue obtained in step (2), pass Add KOH (85% purity) 6.23g, Al(OH) ₃ 0.44g and H ₂ O 37.2ml, age at 30°C for 2h, then transfer to a stainless steel crystallization kettle, and crystallize at 150°C for 24h. After the product is filtered, washed with water and dried, W molecular sieve is obtained. By supplementing 0.42g of KOH, 1.14g of silica-alumina filter residue and 0.46g of Al(OH) ₃ to the mother liquid of molecular sieve, it can be recycled for the preparation of W molecular sieve.

Example 2~6:

The change of each condition in the step (1) of example 2～6 is as shown in table 1, and the dissolution rate of potassium ions in the potassium feldspar is different under different conditions, and the XRD and SEM spectrograms of the potassium feldspar decomposition filter residue are shown in the figure respectively; Example Steps (2), (3) and (4) of 2~6 are the same as Example 1.

Table 1

Examples 7~9:

Steps (1), (3) and (4) of examples 7 to 9 are the same as example 1, and each condition change in step (2) is as shown in table 2, and the time required for the acidification of potassium feldspar decomposition mother liquor is different under different conditions , The morphology of the silica-alumina filter residue obtained by filtration and separation after acidification is also different.

Table 2

Examples 10~16:

Steps (1), (2) and (3) of examples 10 to 16 are the same as in example 1, and the changes of conditions in step (4) are as shown in Table 3. The XRD and SEM spectra of the W molecular sieve obtained under different conditions are respectively as the picture shows.

table 3

Claims (8)

1. a novel method for potassium felspar sand comprehensive utilization, is characterized in that, comprise the steps:

(1) by potassium felspar sand breeze and NaOH-Na ₂cO ₃mixing sub-molten salt solution, by proportioning mixing, is put in polytetrafluoroethyllining lining, then polytetrafluoroethyllining lining is put into autoclave, and be fixed in homogeneous phase stirred reactor, is heated to potassium felspar sand breeze decomposition temperature, reaction for some time; Filtered by reacted grog, wash, filter residue is dried and is cancrinite, and filtrate is potassium feldspar decomposition mother liquor;

(2) in potassium feldspar decomposition mother liquor, CO is passed into ₂carry out carbonating, regulate pH to be 8 ~ 10, make silicon and aluminum precipitation get off to be formed sal filter residue, filtering separation acquisition filtrate, filtrate is by adding NaOH Posterior circle to the decomposition of step (1) for potassium felspar sand;

(3) when after the circulation at least twice from step (1) to step (2), by the pH regulator of the potassium feldspar decomposition mother liquor of acquisition to 5 ~ 8, the sodium in guarantee potassium feldspar decomposition mother liquor and potassium are with NaHCO ₃and KHCO ₃form exist, then filters potassium feldspar decomposition mother liquor and obtain filtrate, then filtrate filtering separation obtained is by least three evaporations, crystallizations be separated, and obtains NaHCO ₃and KHCO ₃, at 200 DEG C, dry decomposition obtains Na ₂cO ₃and K ₂cO ₃, Na ₂cO ₃solid can be cycled to used in the potassium feldspar decomposition of step (1);

(4) the sal filter residue that precipitates of step (2), by adding KOH, Al (OH) ₃and H ₂o, regulation system K ₂o/SiO ₂, Al ₂o ₃/ SiO ₂and H ₂o/SiO ₂proportioning, at a certain temperature aging and crystallization for some time, filtered by product, wash, filter cake is W molecular sieve, and filtrate is W molecular sieve mother liquor, can be cycled to used in the synthesis of W molecular sieve.

2. the novel method of a kind of potassium felspar sand comprehensive utilization according to claim 1, is characterized in that: NaOH-Na in described step (1) ₂cO ₃the concentration of mixing sub-molten salt solution is 50wt% ~ 80wt%.

3. the novel method of a kind of potassium felspar sand comprehensive utilization according to claim 1, is characterized in that: Na in described step (1) ₂cO ₃account for NaOH-Na ₂cO ₃mix 30 ~ 50% of the total alkali content of sub-molten salt.

4. the novel method of a kind of potassium felspar sand comprehensive utilization according to claim 1, is characterized in that: described step (1) potash feldspar ore and NaOH-Na ₂cO ₃mixing sub-molten salt weight ratio is 1:3.0 ~ 6.0.

5. the novel method of a kind of potassium felspar sand comprehensive utilization according to claim 1, is characterized in that: in described step (1), potassium feldspar decomposition temperature is 190 ~ 210 DEG C, and the resolving time is 2 ~ 5h.

6. the novel method of a kind of potassium felspar sand comprehensive utilization according to claim 1, is characterized in that: in described step (2), potassium feldspar decomposition mother liquor passes into CO ₂when carrying out carbonating, the SiO in potassium feldspar decomposition mother liquor ₃ ^2-it is 0.3 ~ 0.6mol/L, CO that concentration controls ₂flow velocity be 0.2 ~ 0.4L/min, adopt mechanical stirring in carbonation, rotating speed is 400 ~ 600r/min.

7. the novel method of a kind of potassium felspar sand comprehensive utilization according to claim 1 or 2 or 3 or 4 or 5 or 6, is characterized in that: in described step (4), W Zeolite synthesis system weight of material proportion optimization is K ₂o/SiO ₂=0.5 ~ 1.5, Al ₂o ₃/ SiO ₂=0.02 ~ 0.15, H ₂o/SiO ₂=35 ~ 55.

8. the novel method of a kind of potassium felspar sand comprehensive utilization according to claim 7, is characterized in that: in described step (4) synthesis W molecular sieve need at 25 ~ 50 DEG C aging 2 ~ 5h, crystallization 12 ~ 48h at 140 ~ 170 DEG C.