CN105800615B - A kind of method that porous elemental silicon powder is prepared using natural silicon aluminium acid salt mineral - Google Patents

Abstract

The invention discloses a method for preparing porous elemental silicon powder by using natural aluminosilicate minerals, which comprises the following steps: fully pulverizing the natural aluminosilicate ores, soaking in dilute hydrochloric acid solution to remove impurities, and obtaining _SiO2 as the main component and Al ₂ O ₃ powders. The powder is fully mixed with the metal reducing agent powder, placed in an atmosphere tube furnace, isolated from air or calcined under the protection of an inert gas for reaction. After the reaction is completed, the product is repeatedly washed, filtered and dried to obtain porous elemental silicon powder. The present invention can reduce the reaction temperature to a large extent, and expand the silicon source material used in the reaction from _SiO2 -based raw materials to natural aluminosilicate minerals, effectively improving the diversity of the microstructure of the products obtained, and at the same time the reduction in the method Metals are not limited to magnesium either, sodium metal is also suitable.

Description

A method for preparing porous elemental silicon powder using natural aluminosilicate minerals

technical field

The invention relates to a method for preparing elemental silicon powder, in particular to a method for preparing porous elemental silicon powder by using natural aluminosilicate minerals as raw materials and utilizing metal thermal reduction.

Background technique

With its unique sponge-like pore structure, special electrical conductivity, large specific surface area, high piezoresistive coefficient, and special photoluminescence phenomenon, elemental silicon material makes it widely used in sensing, microelectronics, micro-optics, Fuel cells and optoelectronic materials applications have their own place. At the same time, porous silicon materials have good biodegradability and biocompatibility, making them unique contributions to pharmaceutical materials such as drug sustained-release agents and biosensors. These advantages make elemental silicon become the object of research by many researchers. The main method for the preparation of elemental silicon has always been the electrochemical corrosion method. However, due to the cumbersome preparation process, high cost, and serious environmental pollution of by-products, the obtained products mostly exist in the form of thin films and the uniformity of the pore structure is poor. Therefore, The development of a new, simple and easy-to-operate method for preparing porous silicon powder has become one of the problems to be solved urgently.

The metal thermal reduction method represented by the magnesia thermal method is a new method for preparing porous silicon materials that has emerged in recent years. Due to its simple process flow, low cost, easy handling of by-products, and good uniformity of the obtained porous silicon materials, etc. advantages, and thus has received widespread attention. The preparation of porous silicon by the magnesia method mostly uses _SiO2 -based natural minerals, such as diatomaceous earth and opal, or artificially synthesized _SiO2 molecular sieves as templates. Silicate minerals are widely distributed in nature. It is known that there are more than 600 kinds of silicate minerals, which constitute about 85% of the total weight of the crustal lithosphere. Among them, aluminosilicate natural ore is an important part of silicate minerals, and its main components are SiO ₂ and Al ₂ O ₃ , containing a small amount of metal cations such as sodium ions and iron ions, and impurities such as sulfides. Natural aluminosilicate minerals are abundant and various in variety, common ones include dickite, illite, kaolinite, anorthite, potassium mica, potassium feldspar and so on. Different types of aluminosilicate minerals have different internal molecular structures, so a variety of porous elemental silicon powders with different pore structures can be obtained using them as raw materials. In addition, unlike the preparation of elemental silicon from silicon dioxide, the removal of SiO ₂ from aluminosilicate minerals also contains a large amount of Al ₂ O ₃ , and these Al ₂ O ₃ will also be removed during the process of preparing elemental silicon , thus creating an elemental silicon powder with a large specific surface area and a more porous structure.

Contents of the invention

In order to overcome the deficiencies in the prior art, the present invention provides a method for preparing porous elemental silicon powder using natural aluminosilicate minerals, which can reduce the cost, effectively improve the microstructure of the product obtained, and convert the silicon source material used in the reaction from _SiO2 -based raw materials are expanded to natural aluminosilicate minerals, and the reduced metal in this method is not limited to magnesium, and metal sodium is also applicable.

The purpose of the present invention is achieved by the following scheme:

A method for preparing porous elemental silicon powder using natural aluminosilicate minerals is provided, comprising the following steps:

1) Fully pulverize aluminosilicate ore, soak in 0.1-1mol/L dilute hydrochloric acid solution to remove impurities, and obtain powder whose main components are SiO ₂ and Al ₂ O ₃ ;

2) Dry the product of step 1) and grind it together with the metal reducing agent powder at a molar ratio of 1:1 to 1:10 to make it fully mixed, put it into an atmosphere tube furnace, isolate the air or under the protection of an inert gas Calcined at 300-800°C for 0.5-12 hours, cooled and taken out;

3) Soak the product after the reaction in step 2) in 0.1-1mol/L dilute hydrochloric acid solution or ethanol solution for 1-24 hours and perform ultrasonic cleaning for 5-60 minutes; immerse the black solid after ultrasonic cleaning in distilled water, dilute HCl solution, HF solution, repeated pickling, filtration, and drying to obtain porous elemental silicon. The purpose of washing with distilled water is to remove by-products such as sodium silicate and sodium aluminate in the reaction; the purpose of acid washing is to remove by-products such as MgO and Mg ₂ Si in the reaction.

In the method for preparing porous elemental silicon powder using natural aluminosilicate minerals, the aluminosilicate ore used in step 1) is a naturally occurring siliceous rock whose main components are SiO ₂ and Al ₂ O ₃ .

A method for preparing porous elemental silicon powder using natural aluminosilicate minerals, the aluminosilicate ores are dickite, illite, kaolinite, anorthite, potassium mica, potassium feldspar, topaz, One of kyanite or sillimanite.

In the method for preparing porous elemental silicon powder using natural aluminosilicate minerals, the metal reducing agent used in step 2) is elemental magnesium powder or sodium metal particles with a certain diameter after wiping the surface with liquid paraffin.

In the method for preparing porous elemental silicon powder using natural aluminosilicate minerals, the inert gas used in step 2) is high-purity nitrogen or high-purity argon.

In the method for preparing porous elemental silicon powder using natural aluminosilicate minerals, the ultrasonic cleaning in step 3) refers to cleaning in ultrasonic waves above 20,000 Hz.

The method for preparing elemental silicon powder by using natural aluminosilicate proposed by the present invention has low cost of raw materials, extremely wide sources and simple preparation method. Due to the loose structure of aluminosilicate ore, the impurities contained in it are easy to remove, which is beneficial for direct application or further processing. The global demand for elemental silicon is extremely large and its application is extremely wide, so the present invention has extremely strong economic value and application prospect.

Description of drawings

Fig. 1 is the X-ray diffraction spectrogram of the porous silicon powder of embodiment 1;

Fig. 2 is the nitrogen adsorption-desorption curve spectrogram of the porous silicon powder of embodiment 1;

Fig. 3 is the scanning electron microscope spectrogram of the porous silicon powder of embodiment 1;

Fig. 4 is the infrared vibration spectrogram of the porous silicon powder of embodiment 1;

detailed description

The steps of the preparation method for preparing porous elemental silicon by using aluminosilicate natural ore are as follows:

1) Remove impurities in aluminosilicate ore, such as MgO, CaO, etc.: fully crush aluminosilicate ore to 1000-10000 mesh, soak in 0.1-1mol/L dilute hydrochloric acid solution for 1-24h. Due to its loose structure and porous shape, aluminosilicate ores are easy to remove because the oxide impurities do not enter the interior of the mineral lattice. Therefore, fully immersing the ore in dilute hydrochloric acid can remove the oxide impurities and obtain a powder whose main components are SiO ₂ and Al ₂ O ₃ .

Aluminosilicate ores are naturally occurring siliceous rocks, including but not limited to dickite, illite, kaolinite, anorthite, potassium mica, potassium feldspar, topaz, kyanite, sillimanite, etc. , whose main components are SiO ₂ and Al ₂ O ₃ .

2) Reaction between ore and metal reducing agent: After drying the ore purified in step 1), fully grind and mix it with a certain amount of metal reducing agent powder (such as metal magnesium powder, metal sodium powder, etc.), and isolate the air (referring to vacuum The permissible range of temperature is 0.1-1MPa) or placed in an atmosphere tube furnace under the protection of inert gas (high-purity nitrogen or high-purity argon), calcined at 300-800°C for 0.5-12h, and the product is cooled take out.

Wherein, the metal reducing agent is one of magnesium powder of 100-300 meshes or sodium metal particles with a certain diameter after wiping off the surface liquid paraffin.

3) Preparation of elemental silicon: soak the product after the reaction in step 2) in 0.1-1 mol/L dilute hydrochloric acid solution or ethanol solution for 1-24 hours, and perform ultrasonic cleaning for 5-60 minutes in an ultrasonic wave above 20,000 Hz. Immerse the black solid after ultrasonic cleaning in distilled water, dilute HCl solution, and HF solution for repeated pickling, centrifugation, and filtration. Seal the centrifuge tube with filter paper and keep it warm at 50-150°C for 8-12 hours. After drying, it will be porous. Elemental silicon.

The dilute hydrochloric acid used is obtained by mixing commercially available concentrated hydrochloric acid and absolute ethanol in a certain volume ratio.

The purpose of washing with distilled water in the preparation process is to remove by-products such as sodium silicate and sodium aluminate in the reaction; the purpose of acid washing is to remove by-products such as MgO and Mg ₂ Si in the reaction.

The porous elemental silicon prepared by the method can be widely used in sensing, microelectronics, micro-optics, fuel cells, photoelectric materials and the like.

Below in conjunction with embodiment further illustrate the present invention.

Embodiment one: take dickite as raw material

1) Take dickite and pulverize it, soak it in 1mol/L dilute hydrochloric acid solution for 1 hour to obtain a powder whose main components are SiO ₂ and Al ₂ O ₃ ;

2) Dried the dickite powder produced in step 1) and mixed it with magnesium powder at a molar ratio of 1:6, put it into a 650°C atmosphere tube furnace, fully calcined it for 4 hours in a vacuum environment, and took it out after cooling.

3) Immerse the product obtained in step 2) in 0.5 mol/L dilute hydrochloric acid solution for 10 h with magnetic force stirring, pour off the supernatant and centrifuge. Pour in distilled water and ultrasonically clean for 10 minutes, then centrifuge and wash repeatedly. Seal the centrifuge tube with filter paper and dry it at 100° C. for 10 h to obtain porous elemental silicon.

Embodiment two: take dickite as raw material

1) Take dickite and pulverize it, soak it in 1mol/L dilute hydrochloric acid solution for 1 hour to obtain a powder whose main components are SiO ₂ and Al ₂ O ₃ ;

2) Dried the dickite powder produced in step 1) and mixed it with magnesium powder at a molar ratio of 1:10, put it into an atmosphere tube furnace at 650°C, fully calcined it for 4 hours in a vacuum environment, and took it out after cooling.

3) Immerse the product obtained in step 2) in 0.1 mol/L dilute hydrochloric acid solution for 24 hours with magnetic force stirring, pour off the supernatant and centrifuge. Pour in distilled water and ultrasonically clean for 5 minutes, then centrifuge and wash repeatedly. Seal the centrifuge tube with filter paper and dry it at 100° C. for 10 h to obtain porous elemental silicon.

Embodiment three: take illite as raw material

1) Take illite and pulverize it, and soak the obtained powder in 0.1mol/L dilute hydrochloric acid solution for 24 hours to remove impurities therein.

2) Dry the illite powder produced in step 1) and mix it with magnesium powder at a molar ratio of 1:1, put it into an atmosphere tube furnace at 800°C for calcination for 0.5h under the protection of argon, and take it out after cooling.

3) The product of step 2) was taken out after cooling, soaked in 1 mol/L dilute hydrochloric acid solution for 1 hour, ultrasonically cleaned for 15 minutes, then centrifuged, washed with distilled water and centrifuged 3 times. Seal the centrifuge tube with filter paper and dry it at 80° C. for 12 hours to obtain porous elemental silicon.

Embodiment four: take illite as raw material

1) Take illite and pulverize it, and soak the obtained powder in 0.1mol/L dilute hydrochloric acid solution for 24 hours to remove impurities therein.

2) Dry the illite powder produced in step 1) and mix it with magnesium powder at a molar ratio of 1:1, put it into an atmosphere tube furnace at 800°C for calcination for 0.5h under the protection of argon, and take it out after cooling.

3) The product of step 2) was taken out after cooling, soaked in 1 mol/L dilute hydrochloric acid solution for 1 hour, ultrasonically cleaned for 15 minutes, then centrifuged, washed with distilled water and centrifuged 3 times. Seal the centrifuge tube with filter paper and dry it at 80° C. for 12 hours to obtain porous elemental silicon.

Embodiment five: take potassium mica as raw material

1) Take potassium mica and pulverize it, and soak the obtained powder in 0.1mol/L dilute hydrochloric acid solution for 16 hours to remove impurities therein.

2) Weigh the metal sodium block, wipe off the surface liquid paraffin, cut it into granules with a diameter of about 3mm with scissors, mix step 1) and metal sodium particles into the porcelain boat at a molar ratio of 1:4, and Put it into an atmosphere tube furnace. Use a vacuum pump to extract to 0.85MPa. The system was put into a furnace at 300°C and fully calcined for 12 hours in a vacuum environment.

3) After cooling the product obtained in step 2), soak it in ethanol solution for 1 hour, ultrasonically clean it for 15 minutes, and then centrifuge. Soak the centrifuged product in 1mol/L dilute hydrochloric acid solution for 1 hour, ultrasonically clean it for 10 minutes, and then centrifuge. Finally, soak the product in HF acid for 30 minutes, and ultrasonically clean it for 20 minutes, then centrifuge it, and dry it at 150°C for 8 hours to obtain porous elemental silicon. .

Claims (6)

1. A method utilizing natural aluminosilicate minerals to prepare porous elemental silicon powder, is characterized in that, comprises the following steps: 1) Fully pulverize aluminosilicate ore, soak in 0.1-1mol/L dilute hydrochloric acid solution to remove impurities, and obtain powder whose main components are SiO ₂ and Al ₂ O ₃ ; 2) Dry the product of step 1) and grind it together with the metal reducing agent powder at a molar ratio of 1:1 to 1:10 to make it fully mixed, put it into an atmosphere tube furnace, isolate the air or under the protection of an inert gas Calcined at 300-800°C for 0.5-12 hours, cooled and taken out; 3) Soak the product after the reaction in step 2) in 0.1-1mol/L dilute hydrochloric acid solution or ethanol solution for 1-24 hours and perform ultrasonic cleaning for 5-60 minutes; immerse the black solid after ultrasonic cleaning in distilled water, dilute HCl solution, HF solution, repeated pickling, filtration, and drying to obtain porous elemental silicon. 2. a kind of method utilizing natural aluminosilicate mineral to prepare porous elemental silicon powder as claimed in claim 1, is characterized in that, the aluminosilicate ore used in described step 1) is the siliceous quality of natural output Rock, whose main components are SiO ₂ and Al ₂ O ₃ . 3. a kind of method utilizing natural aluminosilicate mineral to prepare porous elemental silicon powder as claimed in claim 2, is characterized in that, described aluminosilicate ore is dickite, illite, kaolinite, calcium One of feldspar, potassium mica, potassium feldspar, topaz, kyanite or sillimanite. 4. a kind of method utilizing natural aluminosilicate mineral to prepare porous elemental silicon powder as claimed in claim 1, is characterized in that, described step 2) in the metal reducing agent used is elemental magnesium powder or surface liquid paraffin Sodium metal particles that are wiped clean and have a certain diameter. 5. A method for preparing porous elemental silicon powder using natural aluminosilicate minerals as claimed in claim 1, wherein the inert gas used in step 2) is high-purity nitrogen or high-purity argon. 6. A method for preparing porous elemental silicon powder using natural aluminosilicate minerals as claimed in claim 1, characterized in that the ultrasonic cleaning in step 3) refers to cleaning in ultrasonic waves above 20,000 Hz.