CN1050817C

CN1050817C - Prepn of silicon dioxide powder with controllable nanon size

Info

Publication number: CN1050817C
Application number: CN95102373A
Authority: CN
Inventors: 张立德; 张彪
Original assignee: INST OF SOLID PHYSICS CHINESE
Current assignee: INST OF SOLID PHYSICS CHINESE; Institute of Solid State Physics ISSP of CAS
Priority date: 1995-03-14
Filing date: 1995-03-14
Publication date: 2000-03-29
Anticipated expiration: 2015-03-14
Also published as: CN1117022A

Abstract

The present invention relates to a preparation method of nanometer-sized silicon dioxide powder, which comprises the steps: silicic acid lipid as an original material is hydrolyzed under acid environment, the varieties and quantity of the added silicic acid lipid are adjusted in the hydrolytic process to prepare SiO2 gel, and the gel is dried and processed at a high temperature to prepare white amorphous nanometer SiO2 powder with controllable size and large quantity. The present invention has obvious advantage that the size of the SiO2 powder can be effectively controlled by the mixture ratio of reactant, the hydrolytic temperature and the annealing temperature. The SiO2 powder prepared with the method has the advantages of large quantity, high purity, uniform particle distribution, single particle size, no hard agglomeration and high practicability.

Description

A kind of preparation method of silicon dioxide powder with controllable nanon size

The present invention relates to the preparation method of nanometer grade silica powder.

Nano silicon (SiO ₂) material, because of its size during less than 100nm, the property that conventional silicon-dioxide powdery (size is greater than 1 μ m) do not had can occur and cause that people note widely, have to test to show: when the silica granules size was about 20nm, its resistance was dropped to about 10E5 by 10E11; When it was non-crystalline state, its uv-absorbing occurred unusual; The position of absorption peak presents regular corresponding variation with granularity, and under specific pressure, can present the character that ultraviolet sees through.Because nanometer grade silica powder has many unusual characteristics, so its preparation has caused that current material supply section educational circles notes widely.

Closely during the last ten years, states such as Europe, the United States, Japan have done a few thing in succession, but the part that also all comes with some shortcomings.For example: utilize silicon ester to add alcohol and under weak base (amine water) environment, prepare silicon-dioxide, and reach controllable size by control hydrolysis speed and silicon ester amount.But there is complex process in this method, and the production cycle is long, and the particle size of producing powder is big, by separating organic matters, is defectives such as non-pure silicon dioxide powder between particle.Utilize silane, water, alcohol under alkaline environment, to be prepared into silica dioxide gel in addition.But exist the bigger than normal and particle diameter particle of particle diameter to yield poorly, the removing of C atom is also lacked effective measures, shortcoming such as finished product silicon-dioxide purity is low.Utilize neutralization reaction to generate silicon-dioxide powdery in addition, but exist speed of response wayward, particle directly distributes wide, and size is greater than the shortcoming of 100nm.

In a word, the known method for preparing nanometer grade silica mostly adopts silicate or silicon ester, and hydrolysis generates siliceous organic poly-and body under alkaline environment, heat-treats then, obtains silicon-dioxide powdery.But these methods all exist manufacture craft loaded down with trivial details, the defective that resultant purity is not high.

The object of the invention is, overcomes the deficiency that existing preparation technology exists, and provides a kind of and can obtain nano level, narrow distribution, high purity, hard aggregation-free, controllable size, the preparation method of the silicon-dioxide powdery of high yield.

The present invention adopts silicon ester to add alcohol and is prepared, particularly get silicon ester 255ml, at normal temperatures and pressures with silicon ester, dehydrated alcohol, hydrochloric acid and deionized water by 8: 8～9: 1～1.67: 4～6 volume ratio, the control pH value is under 3～4 sour environment, splash into the cetylamine of 1ml, stir and even after leave standstill the reaction solution cooling and be transparence; Reaction solution in 80～90 ℃ of following water-baths 8～12 hours, is obtained transparent wet gel; Wet gel was dried by the fire 2～5 hours down in 200 ℃, and the gel that must dry burns them 2 hours down in 800～900 ℃ again, obtains the SiO that particle diameter is 20～50nm ₂Powder.

The advantage for preparing nano silica powder with the inventive method is:

One. nano silicon output height, purity height and even particle distribution, the material footpath is single;

Two. the inventive method can be controlled the silicon-dioxide powdery size effectively by proportioning, hydrolysis temperature, the annealing temperature of reactant;

Three. the silicon dioxide powder hard aggregation-free of the inventive method preparation.

The invention will be further described below in conjunction with embodiment.

Embodiment 1: get tetraethoxy, dehydrated alcohol, hydrochloric acid, deionized water, by 24: 27: 3: 30 volume ratio, splash into that the 1ml cetylamine stirs and even after leave standstill the reaction solution cooling, and be transparence, the sour environment of control ratio PH ≈ 3.5, again reaction solution is placed on 80 ℃ of following water-baths 12 hours, obtain transparent wet gel, remove free moisture content, the baking oven of gel being put into 200 ℃ dried by the fire 5 hours, and the gel after will drying is again put into and is preheating to 250 ℃ stove, burnt 2 hours down at 800 ℃, naturally promptly obtain pure white after lowering the temperature Deng body of heater, non-crystalline state, particle diameter is the silicon dioxide powder of 20～30nm.If prepare 1000ml solution according to the above ratio, can obtain 212 gram nano-silica powders, preparation 5000ml solution can obtain the 1Kg nano silica powder.

Embodiment 2. gets tetraethoxy, dehydrated alcohol, hydrochloric acid, deionized water, and by 24: 24: 5: 12 volume ratio was controlled at pH value the sour environment of 3＜PH＜4, add the 1ml cetylamine, remove free-water, 90 ℃ of following water-baths 8 hours, oven dry was about 2 hours in baking oven, put into stove again, burnt 2 hours down at 900 ℃,, promptly obtain pure white, non-crystalline state, particle diameter are the white silicon-dioxide powdery about 50nm.Dispose 5000ml solution according to the above ratio, can obtain 1.2Kg white silicon-dioxide powdery.

Embodiment 1,2 two kind of method, the controllable size that not only can accomplish the silicon-dioxide particle diameter, and can press solution ratio as required and amplify, all can obtain corresponding size, measure big silicon-dioxide powdery.

Claims

1. the preparation method of a silicon dioxide powder with controllable nanon size adopts silicon ester to add alcohol and is prepared, and it is characterized in that:

1.1 get silicon ester 255ml, at normal temperatures and pressures with silicon ester, dehydrated alcohol, hydrochloric acid and deionized water by 8: 8～9: 1～1.67: 4～6 volume ratio, the control pH value splashes into the cetylamine of 1ml under 3～4 sour environment, stir and even after leave standstill the reaction solution cooling and be transparence;

1.2 reaction solution in 80～90 ℃ of following water-baths 8～12 hours, is obtained transparent wet gel;

1.3 wet gel was dried by the fire 2～5 hours down in 200 ℃, and the gel that must dry burns them 2 hours down in 800～900 ℃ again, obtains the SiO that particle diameter is 20～50nm ₂Powder.