阅读说明：本技术 一种纳米棒状霞石及其制备方法 (Nano rod-shaped nepheline and preparation method thereof ) 是由 李瑞丰 滑夏 高志虹 于 2020-05-07 设计创作，主要内容包括：本发明涉及一种利用赤泥对废FCC催化剂进行结构转变得到的纳米棒状霞石,是以碱活化处理的废FCC催化剂和酸活化处理的赤泥为原料,经水热合成反应得到的长度500～600nm、直径约50nm的纳米棒状霞石,其霞石尺寸大小均一、分散均匀,原废FCC催化剂中的重金属氧化物被完全转变,霞石中只有NiT<Sub>x</Sub>O<Sub>y</Sub>尖晶石相存在,NiO态逐渐消失。本发明在制备霞石的同时实现了重金属化合形式的原位无排放转变,转变过程没有二次排放,解决了重金属污染问题。(The invention relates to a nano rodlike nepheline obtained by converting the structure of a waste FCC catalyst by utilizing red mud, which is a nano rodlike nepheline with the length of 500-600 nm and the diameter of about 50nm, is obtained by taking the waste FCC catalyst subjected to alkali activation treatment and the red mud subjected to acid activation treatment as raw materials through hydrothermal synthesis reaction, the dimension and the size of the nepheline are uniform, the dispersion is uniform, the heavy metal oxide in the original waste FCC catalyst is completely converted, and only NiT in the nepheline x O y The spinel phase exists, and the NiO state gradually disappears. The invention realizes the in-situ emission-free transformation of the heavy metal combination form while preparing nepheline, has no secondary emission in the transformation process, and solves the problem of heavy metal pollution.)

1. A nano rod-shaped nepheline is a rod-shaped product obtained by taking an alkali activated waste FCC catalyst and an acid activated red mud as raw materials and performing hydrothermal synthesis reaction, wherein the length of the nano rod-shaped nepheline is 500-600 nm, and the diameter of the nano rod-shaped nepheline is about 50 nm.

2. The method of making nano rod-shaped nepheline of claim 1, the method comprising:

1) mixing the waste FCC catalyst with NaOH by using water according to the mass ratio of the NaOH to the waste FCC catalyst not less than 0.8, heating to the temperature of not less than 500 ℃ for high-temperature alkali activation to obtain a NaOH activated waste FCC catalyst;

2) according to the mass ratio of the red mud to the pure nitric acid (1-5): 1, based on the pure nitric acid in the dilute nitric acid solution, placing the red mud in the dilute nitric acid solution for soaking and activating to obtain nitric acid activated red mud;

3) and mixing the NaOH activated waste FCC catalyst and the nitric acid activated red mud with water to obtain slurry, heating in a closed state to perform hydrothermal crystallization reaction, and preparing the nano rod-shaped nepheline.

3. The method of claim 2, further comprising calcining the feedstock spent FCC catalyst to remove carbon deposits.

4. The method of claim 3, wherein the spent FCC catalyst is calcined by heating to 500-800 ℃.

5. The method for preparing nano rod-shaped nepheline according to claim 3 or 4, characterized in that the waste FCC catalyst is heated and roasted for 4 to 10 hours.

6. The method for preparing nano rodlike nepheline according to claim 2 or 3, characterized in that the mass ratio of the NaOH activated waste FCC catalyst to the nitric acid activated red mud is (5-10): 1.

7. The method for producing nano rod-shaped nepheline according to claim 2 or 3, characterized in that NaOH is added into the waste FCC catalyst, and then water is added and mixed according to the mass ratio of the water to the waste FCC catalyst of (0.5-1): 1.

8. The method for preparing nano rod-like nepheline according to claim 2 or 3, characterized in that the high temperature alkali activation treatment time is 2 to 6 hours.

9. The method for preparing nano rod-like nepheline according to claim 2 or 3, characterized in that the concentration of the dilute nitric acid solution used for activating red mud is 5-20 wt%.

10. The method for preparing nano rod-shaped nepheline according to claim 2 or 3, characterized in that the hydrothermal crystallization reaction is carried out at 120-180 ℃ for 12-24 h.

Technical Field

The invention belongs to the technical field of industrial waste recycling, and particularly relates to nano rod-shaped nepheline prepared by utilizing chemical production waste, in particular to two industrial solid wastes of waste FCC catalyst and red mud, and a preparation method of the nano rod-shaped nepheline.

Background

As the tendency of heavy and inferior crude oil increases, the content of toxic metals in crude oil increases significantly. Conventional crude oil refining technologies are primarily Fluid Catalytic Cracking (FCC) processes that can efficiently convert heavy crude oil into light oils, including gasoline, diesel, kerosene, and the like (FCC)Fuel Process Technol.2011,92, 2235-2240.). However, excessive toxic metals such as vanadium (V), nickel (Ni), iron (Fe), etc. in heavy crude oil can cause the FCC catalyst to be seriousInactivating (Energ. Fuel2016,3010371-10382.), resulting in a collapse of the zeolite active component framework on the catalyst, a sharp reduction of available acid sites and more coke formation (Miner. Eng.2018,127, 1-5.）。

In the process of FCC refining in oil refineries, the FCC catalyst typically resides in a catalytic cracking unit for several minutes and is then transferred to a regenerator where it is rapidly warmed to about 750 ℃ to burn off most of the carbon deposits on the catalyst and maintain the activity of the FCC catalyst (b)Chem. Soc. Rev.2015,44, 7342-7370.). In addition, partially deactivated FCC catalyst may be discharged and replaced with fresh FCC catalyst.

Due to the huge number and production of refineries, over ten thousand tons of spent FCC catalyst are produced each year in our country and continue to increase at an acceleration rate of over 5: (Hydrometallurgy2017,171, 312-319.). However, industrially, most of the spent FCC catalyst is directly dumped into landfills. This results in a large amount of land being occupied and toxic metals, particularly metal oxides, therein can penetrate into the soil, causing groundwater and soil pollution. For example, the state of nickel in the waste FCC catalyst is nickel oxide and spinel, the nickel in spinel state is non-toxic, and the nickel in oxide state can invade organs such as respiratory tract and lung of human body, and poses serious threat to human life safety: (Appl. Catal. A-Gen.2014,486, 176-186.）。

In the national hazardous waste record newly issued by the environmental protection department in 2016, the solid hazardous waste with the dangerous characteristic of T is specifically listed as 251-017-50 of the waste FCC catalyst. Therefore, the spent FCC catalyst is prohibited from direct landfilling and must be disposed of after harmless treatment in accordance with hazardous solid waste disposal requirements.

The composition of the waste FCC catalyst mainly comprises a carrier and heavy metal loaded on the carrier, wherein the carrier contains silicon and aluminum. Therefore, the heavy metals in the waste FCC catalyst can be removed and reused as silicon source and aluminum source (Sep. Purif. Technl.2019,30, 251-257.）。

Literature on removal of heavy metals on spent FCC catalystsMany methods are reported, mainly comprising elution of chemical agents, degradation of biomass and magnetic separation, but the methods are generally complex to operate and expensive, the treatment effect is still to be verified deeply, and the problems of secondary pollution caused by treatment exist (the method is used for treating various kinds of biomass, and the like)Appl. Catal. B-Environ.2001,33, 249-261.）。

The red mud is polluting waste slag discharged in the process of producing aluminum in an aluminum plant. China is the main country for producing and consuming alumina, and the red mud generated by producing alumina is up to millions of tons every year. The red mud is often directly stacked or buried without any treatment, which causes great harm to the environment and the human life safety. The main components of the red mud are alumina and part of ferric oxide. The prior literature reports the treatment of red mud, mainly as building material to make bricks, and also as adsorbent for water treatment: (Conserv. Recy.2019,141, 483-498. )。

Nepheline (CAN) is produced by TO₄A three-dimensional network structure formed by connecting tetrahedra (T = Si, Al) mutually, which is similar to feldspar and belongs to zeolite (C: (C) (C))Micropor. Mesopor. Mat.2019,27494-101.). nepheline has a channel with a pore diameter of 6.21 Å and contains a small cage consisting of six-membered rings belonging to P6₃The space group has good passability. Various cage structures and channels in nepheline can carry multiple cations (mainly Na)⁺，Ca²⁺，K⁺) And anions (CO)₃ ^2-，SO₄ ^2-，PO₄ ^3-，OH^-，Cl^-) And H₂O and CO₂A molecule.

Nepheline has a similar chemical composition to sodalite, but crystallographically nepheline belongs to the hexagonal system and sodalite belongs to the cubic system, the sodalite has β cages with a diameter of 6.26 Å and a pore size of 2.47 Ų⁺、Pb²⁺And Ni²⁺。

The method for preparing nepheline reported in the literature at present mainly utilizes alumina-containing carriers such as clay to prepare nepheline (A), (B), (C), (Micropor. Mesopor. Mat.2011,137, 32-35.). However, these methods generally have the disadvantages of high preparation cost, complex operation flow, long synthesis time, high treatment temperature, and the like. Meanwhile, as the chemical compositions of nepheline and sodalite are similar, sodalite often appears in the process of preparing nepheline, and the nepheline can be obtained only by finely modulating the preparation conditions.

Disclosure of Invention

The invention aims to provide nano rodlike nepheline obtained by converting the structure of a waste FCC catalyst by utilizing red mud, and convert heavy metal nickel oxide in the waste FCC catalyst into a combined state.

The invention provides a preparation method for preparing the nano rod-shaped nepheline by utilizing the waste FCC catalyst and the red mud, which is another object of the invention.

The nano rod-shaped nepheline is a rod-shaped product obtained by taking an alkali activated waste FCC catalyst and an acid activated red mud as raw materials and performing hydrothermal synthesis reaction, and the length of the nano rod-shaped nepheline is 500-600 nm, and the diameter of the nano rod-shaped nepheline is about 50 nm.

Furthermore, the invention also provides a preparation method of the nano rod-shaped nepheline, which comprises the following steps.

1) And mixing the waste FCC catalyst with NaOH by using water according to the mass ratio of the NaOH to the waste FCC catalyst not less than 0.8, and heating to the temperature of not less than 500 ℃ for high-temperature alkali activation to obtain the NaOH activated waste FCC catalyst.

2) And (3) taking the pure nitric acid in the dilute nitric acid solution, and placing the red mud into the dilute nitric acid solution for soaking and activating according to the mass ratio of the red mud to the pure nitric acid (1-5): 1 to obtain the nitric acid activated red mud.

3) And mixing the NaOH activated waste FCC catalyst and the nitric acid activated red mud with water to obtain slurry, heating in a closed state to perform hydrothermal crystallization reaction, and preparing the nano rod-shaped nepheline.

The mass ratio of the NaOH activated waste FCC catalyst to the nitric acid activated red mud is preferably (5-10): 1.

Furthermore, the raw material waste FCC catalyst needs to be calcined to remove carbon deposit and then subjected to high-temperature alkali activation by NaOH. Specifically, the waste FCC catalyst is heated to 500-800 ℃ for roasting.

More preferably, the waste FCC catalyst is heated and roasted for 4-10 hours.

Further, NaOH is added into the waste FCC catalyst, and then water is added and mixed according to the mass ratio of (0.5-1) to 1 of the water and the waste FCC catalyst.

Furthermore, the treatment time of the high-temperature alkali activation is preferably 2-6 h.

Preferably, the concentration of the dilute nitric acid solution for activating the red mud is 5-20 wt%.

In the preparation method of the nano rodlike nepheline, the hydrothermal crystallization reaction is preferably carried out at 120-180 ℃, and the hydrothermal crystallization reaction time is 12-24 hours.

The invention uses waste FCC catalyst activated by high temperature alkali and red mud activated by dilute nitric acid as raw materials to prepare nano rod-shaped nepheline with uniform size and uniform dispersion. Importantly, the heavy metal oxide in the original waste FCC catalyst is completely converted, and only NiT in the nano rod-shaped nepheline_xO_yThe spinel phase exists, and the NiO state gradually disappears.

The treatment of industrial solid waste has the problems of complex flow, high operation and maintenance cost, easy generation of secondary pollution and the like. The invention utilizes the characteristic that nepheline can fix metal ions, takes two industrial solid wastes as raw materials, and realizes the in-situ emission-free conversion of a heavy metal combination form through simple activation treatment of alkali and acid. And the whole conversion process has no secondary discharge, thereby reducing the cost and solving the problem of heavy metal pollution. The invention not only achieves the purpose of 'making waste by waste', but also realizes the vision of 'changing waste into valuable'.

Drawings

Figure 1 is the XRD pattern of the spent FCC catalyst of the example 1 feedstock.

Figure 2 is an SEM image of the spent FCC catalyst of the feed of example 1.

Figure 3 is an XPS plot of Ni in the spent FCC catalyst of the feed of example 1.

FIG. 4 is an XRD pattern of the nano-rod nepheline prepared in example 1.

FIG. 5 is an SEM image of the nano rod-shaped nepheline prepared in example 1.

FIG. 6 is an XPS plot of Ni in the preparation of nano-rodlike nepheline from example 1.

Fig. 7 is an XRD pattern of the sodalite prepared in comparative example 1.

Fig. 8 is an SEM image of the sodalite prepared in comparative example 1.

Fig. 9 is an XPS chart of Ni in the sodalite prepared in comparative example 1.

Detailed Description

The following examples are only preferred embodiments of the present invention and are not intended to limit the present invention in any way. Various modifications and alterations to this invention will become apparent to those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.