A method for preparing high-purity mullite powder with high yield by modified fly ash

A technology for mullite powder and fly ash is applied in the field of high-yield preparation of high-purity mullite powder by alumina sol-modified fly ash, and the preparation of high-purity mullite from fly ash, which can solve the problem of high cost of raw materials and high process technology. Complex, low utilization rate of fly ash and other problems, to achieve the effect of increasing mullite content and high yield

Inactive Publication Date: 2019-07-23
NANCHANG HANGKONG UNIVERSITY
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The current purification process can only remove some impurities, and the mullite content in the obtained mullite ceramics is generally less than 70%
In addition, the existing research work adds a large amount of auxiliary raw materials, resulting in low actual utilization rate of fly ash (< 60%), high raw material cost, complex process and other problems. Therefore, research on the preparation of mullite ceramics from fly ash focuses on Explore high-yield, high-purity mullite powder production technology

Method used

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  • A method for preparing high-purity mullite powder with high yield by modified fly ash
  • A method for preparing high-purity mullite powder with high yield by modified fly ash
  • A method for preparing high-purity mullite powder with high yield by modified fly ash

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Experimental program
Comparison scheme
Effect test

Embodiment 1

[0028] Take 50g of fly ash passed through a 120-mesh sieve, add 15 g of 20% aluminum sol aqueous solution, ball mill and mix for 1 hour to modify the surface of fly ash, dry in a drying oven at 110°C for 2 hours after ball milling, and pass through 120 mesh screen, and the obtained powder is modified fly ash. The modified fly ash was calcined in a muffle furnace at 1100 °C for 2 h, then crushed with a ceramic mortar, and prepared into a suspension with a solid content of 20%, adding ZrO 2 Grinding balls, ball milling for 4 hours, washing with distilled water, suction filtration, and drying to obtain calcined fly ash powder. Utilize X-ray powder diffractometer to test XRD spectrogram, as attached figure 1 As shown, it can be seen that in addition to the mullite phase, the calcined fly ash also contains a glass phase and a quartz phase. Use Jade 6.0 software to fit the full spectrum of the XRD pattern, and analyze the relative content of mullite, which accounts for about 62% ...

Embodiment 2

[0030] Take 30 g of calcined fly ash in Example 1, add 270 ml of NaOH aqueous solution with a concentration of 2 mol / L, ultrasonically disperse it, put it into a hydrothermal reaction kettle with a capacity of 500 ml, keep the temperature at 120 ° C for 1 hour, and then use the concentration Wash with 1 mol / L HCl aqueous solution, and obtain mullite powder after drying. Use an X-ray diffractometer to test the powder XRD spectrum, as attached figure 2 As shown, it can be seen that the glass phase in the mullite powder is completely eliminated, and the powder is composed of a mullite phase and a small amount of quartz phase. Use Jade6.0 software to fit the full spectrum of the XRD spectrum, and analyze the relative content of mullite in the powder, which accounts for about 82% of the powder mass.

Embodiment 3

[0032] Take 10 g of mullite powder in Example 2, add 100 ml of distilled water, use NaOH to adjust the pH value to 11, after mechanical stirring for 10 min, according to the concentration of flotation agent 1 × 10 -3 mol / L, add flotation agent sodium dodecylsulfonate, stir for 2 minutes, flotation and scrape foam for 6 minutes, after the flotation is completed, the foam product and the product in the tank are cleaned, filtered, and dried to obtain the quartz separated by flotation. High-purity mullite powder. Utilize X-ray diffractometer to test powder XRD spectrogram, as attached image 3 As shown, it shows that basically only the mullite phase remains in the powder. Use Jade 6.0 software to fit the full spectrum of the XRD pattern, and analyze the relative content of mullite in the powder, which accounts for about 98.2% of the powder mass. The morphology of the high-purity mullite powder is observed by scanning electron microscopy, as shown in attached Figure 4 As shown...

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Abstract

The invention discloses a method for preparing high-purity mullite powder with high yield by modified fly ash, which belongs to the technical field of fine ceramics. The invention includes the following process steps: (1) adding 2‑8% aluminum sol to the fly ash powder, and mixing by ball milling to realize the coating modification of the surface of the fly ash powder particles; (2) modifying the powdered coal The ash is calcined at a certain temperature, so that the mullite content in the fly ash reaches 60-70%, and the mullitization of the fly ash powder is realized; (3) The calcined fly ash is hydrothermally treated in an alkaline aqueous solution , and use an acidic aqueous solution to remove the glass phase and other impurity oxides (such as CaO, MgO, Na 2 O, K 2 O, Fe 2 o 3 ) to obtain mullite powder; (4) adopt reverse flotation technology to remove quartz impurities in mullite powder, and prepare high-purity mullite powder with a purity greater than 98%.

Description

technical field [0001] The invention relates to a method for preparing high-purity mullite from fly ash, in particular to a method for preparing high-purity mullite powder with aluminum sol modified fly ash with high yield, and belongs to the field of fine ceramics. Background technique [0002] Fly ash, also known as fly ash, is the fine ash in the flue gas after coal combustion, the main solid waste of thermal power plants, and its SiO 2 and Al 2 o 3 The total content is higher than 60%. As early as the beginning of the 20th century, some developed countries have begun to study fly ash, and attach great importance to the resource utilization of fly ash. Therefore, the comprehensive utilization rate of fly ash is very high, and it has been widely used in building materials, construction, transportation, etc. , chemical industry, agriculture and other fields ( Z.T. Yao et al. A comprehensive review on the applications of coal fly ash[J]. Earth-Science Reviews, 141 (201...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C04B35/185C04B35/626
CPCC04B35/185C04B35/62605C04B35/62645
Inventor 卢金山丛欣泉曾佑鹏李晨嵘
Owner NANCHANG HANGKONG UNIVERSITY
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