[0037] Example 1
[0038] The coal slime used in this embodiment is the coal slime produced in the coal washing and processing process of Huangling No. 1 Mine, and the method for preparing the 13X type molecular sieve by using the coal slime includes the following steps:
[0039] Step 1. Calcination and activation: grind the coal slime and pass it through a 200-mesh sieve, then place the sieved undersize in a ash pan and evenly spread it, calcined at 800°C for 2.5 hours, and cooled naturally to obtain coal slime ash; The chemical composition of the slime ash is shown in Table 1:
[0040] Table 1 Main chemical components of slime ash (wt%)
[0041]
[0042] Step 2, acid leaching to remove impurities: mix 30 mL of hydrochloric acid solution with a concentration of 6 mol/L and 10.00 g of the slime ash described in step 1, stir and react at 95 ° C for 4.5 h, after the reaction is completed, filter while hot to obtain filter residue, the filter residue is dried for later use; the dried filter residue is detected, and the SiO in the dried filter residue is 2 The content reaches 60.06wt%, Al 2 O 3 The content is 11.04wt%, Fe 2 O 3 The content is 0.85wt%;
[0043] Step 3, alkali melting: mix 10.00 g of solid NaOH with 5.00 g of the filter residue after drying in step 2, place it in a silver crucible, and perform alkali melting for 2 hours at a temperature of 400° C. to obtain molten slag;
[0044]Step 4, forming gel: add 1.16g sodium metaaluminate and 104g water to the slag described in step 3, stir to obtain a mixture, and the ratio of silicon to aluminum in the obtained mixture is 4:1, wherein the ratio of silicon to aluminum is SiO 2 and Al 2 O 3 molar ratio meter;
[0045] Step 5, aging and crystallization: aging the mixture described in step 4 at 40° C. for 14 hours, and then crystallizing the aged mixture at 100° C. for 9 hours to obtain a solid-liquid mixture;
[0046] Step 6, washing and drying: performing suction filtration on the solid-liquid mixture described in step 5 to obtain a filter cake, washing the filter cake with deionized water and drying to obtain a 13X molecular sieve; the drying temperature is 105° C., The drying time was 12h.
[0047] The molecular sieves prepared in this example were characterized by XRD and FTIR, and the results were shown in figure 1 and figure 2. figure 1 According to the XRD diffraction pattern of the molecular sieve prepared in this example, through the analysis of the diffraction peak position, the product phase is a single 13X type molecular sieve. Table 2 is a data comparison table of the standard spectrum (PDF38-0237) of the molecular sieve prepared in this example and the 13X type molecular sieve.
[0048] Table 2 Comparison of standard spectrum diffraction data of 13X type molecular sieve with XRD diffraction data of 13X type molecular sieve prepared in Example 1
[0049]
[0050] As can be seen from Table 2, the position of the diffraction peak of the molecular sieve prepared in this example is consistent with the standard spectrum, indicating that the product is a pure 13X type molecular sieve.
[0051] figure 2 Infrared spectrum (FTIR) figure of the molecular sieve prepared in this example, 984cm in the figure -1 T-O (T represents Si or Al) antisymmetric stretching vibration absorption peak; 668cm -1 is the symmetric stretching vibration absorption peak of T-O; 460cm -1 It is the T-O bending vibration absorption peak, and these groups of absorption peaks belong to the internal vibration of the tetrahedron. 1061cm -1 It is T-O-T opposing stretch vibration absorption peak; 748cm -1 It is the absorption peak of T-O-T symmetrical stretching vibration; 560cm -1 is the double six-membered ring vibration absorption peak. These three groups of absorption peaks are the tetrahedral external connection vibrations in the crystal. From the analysis of the figure, it can be seen that the product prepared in this example has a typical molecular structure of 13X type molecular sieve, which further proves that the product prepared in this example is a 13X type molecular sieve, which is similar to 13X type molecular sieve. figure 1 The XRD analysis results are in good agreement.
[0052] The molecular sieves prepared in this example were characterized by SEM, Figure 3 to Figure 6 All are the scanning electron microscope (SEM) images of the molecular sieve prepared in this example, and the magnifications are 1000, 3000, 5000 and 10000 in turn. It can be seen from the figure that the crystal form of the 13X type molecular sieve observed at 1000 times is spherical. The particle size is uniform. With the increase of the magnification, it can be seen that the 13X molecular sieve has a polyhedral shape. When the magnification is 10,000 times, it can be clearly seen that the surface of the grain is patterned, which is related to the crystallization habit of the 13X molecular sieve. The surface structure pattern of the 13X zeolite crystal is the superimposed track of the β-cage tetrahedron on each face group. The basic structural unit in the 13X molecular sieve crystal is [Al-O 4 ] 5- and [Si-O 4 ] 4- tetrahedron. The X-type zeolite grows in an unforced state under hydrothermal conditions, [Al-O 4 ] 5- and [Si-O 4 ] 4- The tetrahedrons are connected to each other to form four-membered rings and six-membered rings, and then the four-membered rings and six-membered rings are connected to each other to form large-dimensional growth unit hexagonal column cages and beta cages. The beta cages are connected to each other like diamond crystals. ; The carbon atoms in the diamond structure are replaced by β cages, and adjacent β cages are connected by hexagonal column cages, so that each β cage uses 4 six-membered rings to connect with other β cages in the tetrahedral direction, forming The crystal structure of 13X-type zeolite.
[0053] The 13X type molecular sieve prepared in this example was subjected to N 2 Sorption test, N 2 Adsorption isotherms see Figure 7. As can be seen from the figure, the 13X type molecular sieve prepared in this example has a low temperature N 2 The adsorption isotherm is type I, which indicates that the 13X type molecular sieve is dominated by micropores. When the relative pressure is low, there is already a large adsorption. With the increase of the relative pressure, the adsorption capacity increases sharply; there is a hysteresis in the desorption process. ring, which is due to the capillary condensation phenomenon during the desorption process, resulting in the adsorbed N 2 The molecule failed to desorb completely. This is normal for molecular sieve adsorption.
[0054] Figure 8 The pore size distribution diagram of the 13X type molecular sieve prepared in this example, the average BET adsorption pore size of the 13X type molecular sieve is 1.99nm, which belongs to micropores, and the BET adsorption surface area reaches 645.55m 2 /g, and the pore structure parameters are shown in Table 3.
[0055] Table 3 Pore structure parameters of the 13X type molecular sieve prepared in Example 1
[0056] sample
[0057] The indexes of the 13X type molecular sieve prepared in this example are compared with those in the chemical industry standard HG/T2690-2012 "13X molecular sieve", and the results are shown in Table 4.
[0058] The comparison of the 13X type molecular sieve prepared in the embodiment 1 of table 4 and each index in the chemical industry standard
[0059]
[0060] As can be seen from Table 4, the 13X type molecular sieves prepared in this example all meet the standard of 13X type molecular sieves.
