阅读说明：本技术 一种利用工程类弃土通过水热碱法合成方沸石的工艺 (Process for synthesizing analcite by using engineering waste soil through hydrothermal alkaline method ) 是由 陈洪 杨大仲 于 2019-12-03 设计创作，主要内容包括：本发明公开了一种利用工程类弃土合成方沸石的工艺方法,所述晶体类型为方沸石,形貌为球状。所述方沸石的合成方法为按照一定物料配比将含有铝源和部分硅源的弃土、无机碱、外加硅源和水混合均匀,经过陈化、晶化、洗涤、干燥后得到含有少量二氧化硅杂相的方沸石产品。本发明提供的方沸石晶型良好,制备方法简单易行。(The invention discloses a process method for synthesizing analcite by utilizing engineering waste soil, wherein the crystal type is analcite and the shape is spherical. The method for synthesizing the analcime comprises the steps of uniformly mixing waste soil containing an aluminum source and a part of silicon source, inorganic base, an additional silicon source and water according to a certain material ratio, and aging, crystallizing, washing and drying to obtain an analcime product containing a small amount of silicon dioxide impurity phase. The analcime provided by the invention has good crystal form, and the preparation method is simple and easy to implement.)

1. A method of synthesizing analcime using engineered waste soil, said analcime having the following characteristics: the crystal type of the zeolite is analcime, the particle size range is 10-20 mu m, and the synthesis method comprises the following steps:

(1) carrying out crushing, grinding, dewatering and screening operations on the engineering waste soil, wherein the water content of the dewatered waste soil material is less than or equal to 5%; the granularity is less than or equal to 0.60 mm.

(2) Uniformly stirring inorganic alkali, waste soil containing an aluminum source and part of a silicon source, an additional silicon source and water according to a certain material ratio, and aging to obtain silicon-aluminum gel;

(3) and (3) carrying out hydrothermal crystallization treatment on the silicon-aluminum gel obtained in the step (2), and washing and drying to obtain the analcime product.

2. The synthesis method according to claim 1, wherein the inorganic base in step (2) can be one or more of NaOH, KOH and LiOH; the aluminum source is all from engineering waste soil; the silicon source is selected from engineering waste soil and an additional silicon source, and the additional silicon source can be one or more of quartz, sand, white carbon black, silica gel, silica sol or water glass.

3. The synthesis method according to claim 1, wherein the molar ratio of the inorganic base (such as NaOH), the silicon source, the aluminum source and the water in the silica-alumina gel in step (2) is 2-20 NaOH: 1-15 SiO₂:A1₂O₃:30～200H₂O。

4. The synthesis method according to claim 3, wherein the preferable molar ratio of the inorganic base (such as NaOH), the silicon source, the aluminum source and the water in the silica-alumina gel in step (2) is 4-12 NaOH: 2-10 SiO₂:A1₂O₃:50～150H₂O。

5. The synthesis method according to claim 1, wherein the molar ratio of Si to Al in the silicon-aluminum gel in the step (2) is 1-10; the molar ratio of the addition of the inorganic base is 0.3-2.0 of NaOH/(Si + Al); the liquid-solid ratio L/S is 1-10. The stirring time is 2-36 h.

6. The synthesis method according to claim 5, wherein the molar ratio of Si to Al in the silicon-aluminum gel in the step (2) is Si: Al is 1-5; the molar ratio of the addition of the inorganic base is 0.5-1.5% of NaOH/(Si + Al); the liquid-solid ratio L/S is 1-6. The stirring time is 6-24 h.

7. The synthesis method according to claim 1, wherein the aging temperature in the step (2) is 20-70 ℃; the aging time is 2-48 h.

8. The synthesis method according to claim 7, wherein the aging temperature in the step (2) is 25-60 ℃; the aging time is 4-16 h.

9. The synthesis method according to claim 1, wherein the crystallization temperature in the step (3) is 140-260 ℃; the crystallization time is 3-48 h.

10. The synthesis method according to claim 9, wherein the crystallization temperature in the step (3) is 160-220 ℃; the crystallization time is 6-36 h.

11. The synthesis method according to claim 1, wherein in the washing process in the step (3), the product is washed 1-2 times by using acidic water with the pH value of 2; then washing the product with deionized water for 2-4 times until the product is neutral; and finally, carrying out ultrasonic cleaning treatment on the product turbid liquid according to the requirement.

12. The synthesis method according to claim 1, wherein the drying temperature in the step (3) is 60-140 ℃, and the drying time is 6-18 h.

13. A analcime synthesized using engineered waste soil, characterized by: the analcime is of a crystal type, has a particle size of 10-20 mu m, and has a small amount of silicon dioxide impurity phase, and is synthesized by the synthesis method of any one of claims 1-12.

Technical Field

The invention relates to the field of solid waste treatment and porous inorganic material synthesis, in particular to a process for synthesizing analcime by utilizing engineering waste soil and application thereof.

Background

The engineering waste soil is a component of construction waste and mainly comes from engineering projects such as real estate construction, underground pipe gallery laying, subway construction and the like. With the acceleration of the pace of urban construction in China and the large-scale rise of capital construction projects, the production amount of project waste soil is increased rapidly, but the waste soil is treated by a single means at present and is difficult to treat. And due to the fact thatThe spoil produced by the capital construction project has loose soil property, steep accumulation surface and serious soil erosion, which causes serious urban water and soil loss and spoil stockpiling management problems. At present, the amount of waste soil generated in China every year is billions of meters³The above; although governments at all levels actively build spoil disposal farms and dispose of spoil by land, sea, and the like, the above methods have high labor costs, transportation costs, and land occupation costs, and are not conducive to large-scale disposal of spoil. Moreover, the spoil disposal site can only temporarily store spoil, and as the amount of the spoil to be accumulated becomes larger and larger, if the spoil cannot be effectively utilized, great environmental and economic problems will be caused.

Analcime has the characteristics of no toxicity, no pollution, good acid-base stability and the like. By virtue of its effective metal cation exchange capacity and surface adsorption capacity, analcime is widely used in the fields of softening water quality, catalyzing, adsorbing, separating, trapping or solidifying toxic heavy metal ions in water and soil, etc.

At present, patent for preparing analcime such as CN 103046111A, a method for preparing nano analcime by using fly ash uses high-temperature roasting process, and has excessive energy consumption and higher cost. In addition, chinese patent No. CN 201310274337.7 discloses a method for preparing large-size analcite from geopolymer, but the raw material used in the method is expensive.

Disclosure of Invention

Aiming at the fact that the engineering waste soil in China has huge production amount and cannot be effectively treated and the defects of the conventional analcime synthesis technology, the invention provides analcime synthesized by utilizing the engineering waste soil and a process method thereof. The invention is technically characterized in that: under the premise of not introducing zeolite seed crystals, a template agent and an aluminum source, only adding a cheap silicon source without using a high-temperature calcination process, and directly converting silicon-aluminum components in the waste soil into analcite through normal-temperature alkaline activation and hydrothermal treatment. The process is simple and feasible, and has high synthesis speed and high efficiency. The analcime provided by the invention has uniform particle size, and the crystal type of the analcime is analcime; the shape is spherical, and the particle size range is 10-20 mu m.

The engineering waste soil is generally from building foundation excavation, tunnel excavation, building demolition waste soil and waste soil generated in foundation construction. The components are generally silicon-aluminum-calcium salt minerals, and the water content (2-20%) of soil particles has large span. The properties of the spoil are poor, such as mechanical property, mineral property and the like, and the spoil generally comprises fine soil, sandy soil, gravel or mixed soil of the fine soil, the sandy soil and the gravel. The engineering waste soil is difficult to meet the requirements of compaction, particle size, purity and the like of conventional soil, and can not be effectively used for roadbed compaction, brick burning and the like.

The invention provides a synthesis method of analcime, which comprises the following steps:

(1) carrying out crushing, grinding, dewatering and screening operations on the engineering waste soil, wherein the water content of the dewatered waste soil material is less than or equal to 5%; the granularity is less than or equal to 0.60 mm.

(2) Uniformly stirring inorganic alkali, waste soil containing an aluminum source and part of a silicon source, an additional silicon source and water according to a certain material ratio, and aging to obtain silicon-aluminum gel;

(3) and (3) carrying out hydrothermal crystallization treatment on the silicon-aluminum gel obtained in the step (2), and washing and drying to obtain the analcime product.

In the synthesis method of analcime of the present invention, the inorganic base in step (2) may be one or more of NaOH, KOH, LiOH; the aluminum source is all from engineering waste soil; part of the silicon source is from engineering waste soil, and the additional silicon source can be one or more of quartz, sand, white carbon black, silica gel, silica sol or water glass.

In the synthesis method of the analcime, the molar ratio of the inorganic base (taking NaOH as an example), the silicon source, the aluminum source and the water in the silicon-aluminum gel in the step (2) is 2-20 NaOH: 1-15 SiO₂:A1₂O₃:30～200H₂O, preferably 4 to 12NaOH:2 to 10SiO₂:A1₂O₃:50～150H₂O。

In the synthesis method of analcime, the molar ratio of Si to Al in the silicon-aluminum gel in the step (2) is 1-10, preferably 1-5. The molar ratio of the added inorganic base is 0.3-2.0, preferably 0.5-1.5. The liquid-solid ratio L/S is 1 to 10, preferably 1 to 6.

In the synthesis method of analcime, the stirring and aging process in the step (2) is carried out for 2-36 h, preferably 6-24 h; the aging time is 2-48 h, and the preferable time is 4-16 h; the aging temperature is 20-70 ℃, and the preferred temperature is 25-60 ℃.

In the synthesis method of the analcime, the crystallization temperature in the step (3) is 140-260 ℃, preferably 160-220 ℃, and the crystallization time is 3-48 hours, preferably 6-36 hours.

In the synthesis method of analcime, in the washing process in the step (3), acid water with the pH value of 2 is used for washing for 1-2 times, and deionized water is used for washing a product for 4 times until the pH value is neutral. And finally, carrying out ultrasonic cleaning treatment on the product turbid liquid according to the requirement. Drying the analcite at the temperature of 60-140 ℃; the drying time is 6-18 h. The final product analcite has a small amount of silica heterogenous phase.

In the aspect of treating heavy metal polluted water, the analcime provided by the invention can be used as an adsorbent or a purifying agent. The analcime product has excellent adsorptive separation properties, especially for solutions containing lithium and cesium ions. In the aspect of restoring saline-alkali soil and heavy metal contaminated soil, the analcime provided by the invention can be used as a curing agent. Meanwhile, the analcime product can also be used as a catalyst carrier and a chromatographic column filler.

Compared with the prior art, the analcime and the synthesis method thereof provided by the invention have the following advantages: the synthetic raw materials of the donor zeolite provided by the invention are waste engineering waste soil, inorganic base and cheap silicon source. The material cost is low, the synthetic method has simple process, convenient operation and mild reaction condition, and is very suitable for large-scale industrial production.

The invention has the beneficial effects that: the synthesis process of analcime provided by the invention fully utilizes silicon and aluminum components in engineering waste soil. The solid waste with large conservation quantity, namely the engineering waste soil, is successfully converted into the porous inorganic material analcite with economic value, has certain economic value, and provides a new resource approach for solving the problems of accumulation and reutilization of the waste soil in China.

Drawings

Figure 1 is the XRD spectrum of the analcime synthesized in example 1.

FIG. 2 is an SEM spectrum of the analcime synthesized in example 1.

Figure 3 is an XRD spectrum of the analcime synthesized in example 2.

Figure 4 is the XRD spectrum of the analcime synthesized in example 3.

Detailed Description

In order to make the technical scheme of the present invention better understood by those skilled in the art, the following detailed description of the synthesis method of analcime of the present invention is provided with reference to the accompanying drawings and specific examples, but not limited to the examples.

The engineering waste soil raw material is crushed, ground, dried and screened to obtain a powder raw material, and the chemical components are as follows (%):

TABLE 1 chemical composition analysis results (W) of the waste soil powder_B％)

Composition (I)

Al2O3

SiO2

Fe2O3

K2O

TiO2

CaO

other

The content is [ wt%]

39.6

38.7

10.0

4.7

2.9

2.5

<2

The main composition of the waste soil powder is as follows: quartz, dickite, and ferrierite.