Method for firing porous cristobalite at low temperature by adopting diatomite as raw material

A technology of diatomite and cristobalite is applied in the field of low temperature firing of porous cristobalite, which can solve the problems of limited industrial application of products, various kinds of additives, complicated processes, etc., and achieve the effects of abundant reserves, low price and simple process

Active Publication Date: 2014-05-07
GUANGZHOU INST OF GEOCHEMISTRY - CHINESE ACAD OF SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] The purpose of the present invention is to overcome the deficiencies of high energy consumption, complex process, various additives and limited industrial application of products in the existing cristobalite preparatio

Method used

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  • Method for firing porous cristobalite at low temperature by adopting diatomite as raw material
  • Method for firing porous cristobalite at low temperature by adopting diatomite as raw material
  • Method for firing porous cristobalite at low temperature by adopting diatomite as raw material

Examples

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Embodiment 1

[0027] Weigh 0.8g of sodium metasilicate nonahydrate, dissolve it in 10ml of ultra-pure water, add 5g of diatomaceous earth powder, stir the suspension thoroughly, put it in an oven for 5 hours at 80°C, and dry it. The dried solid is placed in In a muffle furnace, the temperature was raised to 600° C. at a rate of 5° C. / min, and kept at 600° C. for 24 hours to obtain porous cristobalite.

[0028] In this example, the mass fraction of sodium metasilicate in the additive solution is 7.20%, and diatomaceous earth is calcined at 600°C for 24 hours and all of them are converted into cristobalite. For specific diffraction results, refer to figure 1 . The generated cristobalite material has a porous structure with a pore size between 200-500nm, and the microscopic morphology of the material refers to figure 2 . Mercury intrusion experiment measured that the pore diameter of porous cristobalite material is mainly distributed between 250-300nm, belonging to nanoscale pores, and 2.5-...

Embodiment 2

[0030] Weigh 2.1g of sodium metasilicate nonahydrate, dissolve it in 10ml of ultra-pure water, add 2g of diatomaceous earth powder, stir the suspension thoroughly, put it in an oven at 80°C for 2 hours, and dry the dried solid in In a muffle furnace, the temperature was raised to 600° C. at a rate of 5° C. / min, and kept at 600° C. for 24 hours to obtain porous cristobalite.

[0031] In this example, the mass fraction of sodium metasilicate in the additive solution is 17.33%, and diatomaceous earth is calcined at 600°C for 24 hours to form cristobalite. For specific diffraction results, refer to Figure 4 . The thermal conductivity of the material at room temperature is 0.16W / m K, and the thermal diffusivity is 0.23mm 2 / s, good thermal insulation performance.

Embodiment 3

[0033] Weigh 0.8g of sodium metasilicate nonahydrate, dissolve it in 10ml of ultra-pure water, add 5g of diatomaceous earth powder, stir the suspension thoroughly, put it in an oven for 5 hours at 80°C, and dry it. The dried solid is placed in In a muffle furnace, the temperature was raised to 700° C. at a rate of 5° C. / min, and kept at 700° C. for 24 hours to obtain porous cristobalite.

[0034] In this example, the mass fraction of sodium metasilicate in the additive solution is 7.2%, and diatomaceous earth is calcined at 700°C for 24 hours to form cristobalite. For specific diffraction results, refer to Figure 5 . The thermal conductivity of the material at room temperature is 0.078W / m K, and the thermal diffusivity is 0.29mm 2 / s, in line with the requirements of thermal insulation materials, good thermal insulation performance.

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Abstract

The invention discloses a method for firing porous cristobalite at low temperature by adopting diatomite as a raw material. The method comprises the following steps of: adding diatomite powder into an additive solution, wherein the addition amount of diatomite is 1g/2-5ml according to the ratio of the mass of the diatomite/the volume of the additive solution; fully stirring, and then drying, wherein the additive solution is sodium metasilicate or alkali-metal silicate solution with the mass fraction being 7.20-17.33%; heating the dried solids to 600-800 DEG C, and calcining for 12-24 hours to obtain the porous cristobalite. The method disclosed by the invention has the beneficial effects that since the calcining temperature is low, the cristobalite product retains the morphology of the cristobalite and has abundant pore-channel structures so as to achieve unique and good heat retaining property. The prepared cristobalite has the intrinsic property of other synthesized cristobalites, also retains the morphology of the cristobalite and has abundant pore-channel structures so as to achieve good heat retaining property. The method disclosed by the invention has the advantages of low energy consumption, simple process and low cost and the product has high potential industrial value.

Description

Technical field: [0001] The invention specifically relates to a method for firing porous cristobalite at a low temperature using diatomite as a raw material. Background technique: [0002] Cristobalite, also known as cristobalite, white silica, tetragonal crystal phase, is a kind of quartz. Cristobalite is widely used in rubber, plastics, coatings, ceramics and other industrial fields due to its excellent properties such as thermal stability, thermal shock resistance, insulation and acid resistance (Lei Yun et al., Silicate Bulletin, 2011; Chen Meiyi et al., Foundry, 1993). Cristobalite has a non-porous structure, dense silicon skeleton, and high thermal conductivity, which is 2.5W / m·K at room temperature (translated by Guo Jingrong, 1995). It does not have thermal insulation performance and is difficult to be used as thermal insulation material. [0003] The content of cristobalite in nature is very small, and only a small amount of output exists in volcanic rocks. There...

Claims

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Application Information

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IPC IPC(8): C01B33/12
Inventor 袁巍巍刘冬谭道永于文彬袁鹏
Owner GUANGZHOU INST OF GEOCHEMISTRY - CHINESE ACAD OF SCI
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