CN1113216A

CN1113216A - Production process for extracting silicon dioxide

Info

Publication number: CN1113216A
Application number: CN 95114827
Authority: CN
Inventors: 吴国华
Original assignee: Individual
Current assignee: Individual
Priority date: 1995-03-28
Filing date: 1995-03-28
Publication date: 1995-12-13
Anticipated expiration: 2015-03-28
Also published as: CN1039898C

Abstract

The present invention relates to a production process for extracting silicon dioxide. Under the condition of heating and pressurizing the rice husk ashes, boiler ashes and calcined soda solution are chemically reacted in an agitating reactor, and then the above-mentioned materials are passed through such processes of filtering, cooling, filtering, beating and neutralizing, filtering, drying and high-temp. drying. This method can directly extract silicon dioxide by using the reduction reaction characteristics of sodium carbonate and silicon dioxide, so that it can take the place of gas-phase method, and can be substituted for oxistent miscellaneous process which uses the carbonized rice husks to produce silicon dioxide. It can reduce cost, make product have activity, colour pure, and can meet the requirements for various purposes.

Description

Production process for extracting silicon dioxide

The present invention relates to extract in the chemical process producing and manufacturing technique of silicon-dioxide.

At present, the traditional method of producing silicon-dioxide both at home and abroad is the vapor phase process and the precipitator method, though the silicon-dioxide quality that vapor phase process is produced is good, the widespread use of various industries is not satisfied in the processing requirement strictness.The precipitator method are the main method of producing silicon-dioxide at present, but because the extensive application of sodium hydroxide, not only cost is higher, and the purity of silicon-dioxide does not reach specification of quality when reaction.The prior art approaching with the present invention, as the patent No.: 881054291, by name: " rice hull ash coproduction water glass and activated carbon ", a kind of water glass and activated carbon production technology are disclosed, be with rice hull ash under the condition of pressurization of heating with caustic soda soln water generation reaction glass, salt and reaction generates silicon-dioxide again.Because the condition restriction of this technology is produced indirectly rather than directly, thereby the purity of silicon-dioxide is subjected to certain restriction, leads a series of problems such as having made the product performance difference.

The objective of the invention is to utilize the common rice hull ash, the Boiler Ash that are easy to get, a kind of similar precipitator method are proposed, but from having changed the original production process method in fact, and can substitute the silicon-dioxide that vapor phase process is produced in a large number in some place, make product cost low, have activity, color pure, satisfied multi-purpose needs.

Technical scheme of the present invention is achieved in that

A. utilize rice hull ash, Boiler Ash to be 140-170 ℃ in temperature, reaction pressure is 5-7MPa, and the reaction times is under 4-5 hour the condition, to carry out chemical reaction in stirred autoclave, reaction equation with soda ash solution:

B. behind the chemical reaction liquid is carried out the first time with chamber filter press and filter, to 20-22 ℃, filtrate has a large amount of Sio to filtrate in process of cooling through the water cooler fast cooling ₂Gelatinous precipitate is separated out: following chemical reaction takes place when separating out:

C. yellow soda ash that decomposites and the silicon-dioxide of separating out are carried out the filtration second time, and then the silicon-dioxide in the chamber filter press is washed to neutrality with filtering clear water;

D. with the silicon-dioxide in the chamber filter press, after defibrination making beating acid neutralization, precipitate 8 hours, filter with chamber filter press for the third time, remove salt solution, in the hot-air flow drying system more than 300 ℃, dry, can obtain more than 325 orders, the senior superfine active silicon-dioxide of following two kinds of 325 orders.

E. again this product is dried at 800-1000 ℃ sintering oven, can obtain the silica product that replaces vapor phase process to produce.

The silicon-dioxide that adopts this processing method to produce, product colour is pure, purity is high, and this feature of reduction reaction takes place in this technology utilization yellow soda ash and silicon-dioxide under differing temps, participate in chemical reaction directly, has therefore improved purity, output; Reduced cost, raw material is easy to get simultaneously, realized without strong acid, highly basic, the safe and reliable free of contamination advantage of Working environment, because product has characteristics such as good insulation preformance, wear-resisting, high reactivity, be industry good additive such as silicon rubber, military project, space flight, medicine, food, makeup, paint, can satisfy the needs of different purposes.

Accompanying drawing is a process flow sheet of the present invention;

Be a most preferred embodiment of the present invention below; As figure: in the sodium carbonate solution 8000kg adding stirred autoclave with rice hull ash, Boiler Ash (over dry calculations) 500kg and 8%, temperature is 140-170 ℃, and reaction pressure is 5-7MPa, and the reaction times is to carry out chemical reaction under 4-5 hour the condition.Behind the chemical reaction, immediately liquid being carried out the first time with chamber filter press filters, filtrate is through cooling off fast cooling to 20-22 ℃, then there is silicon-dioxide to separate out, with decomposite yellow soda ash, carrying out the second time again filters, silicon-dioxide in the chamber filter press is extremely neutral with filtering the clear water washing, silicon-dioxide in the chamber filter press is taken away, after defibrination making beating acid neutralization, precipitate 8 hours, filter with chamber filter press for the third time, remove salt solution, in the hot-air flow drying system more than 300 ℃, dry, can obtain more than 325 orders, the senior superfine active silicon-dioxide of following two kinds of 325 orders, again the product that obtains is dried in 800-1000 ℃ hyperthermia drying stove, promptly obtain highly purified silica product.

The performance of silica product:

Dioxide-containing silica % 98.75

The appearance white powder

Weight loss on heating % 0.61

Burning decrement % 0.74

PH??7.5

Screenings 0.45

Total copper content (mg/kg) 10

Total iron-holder (mg/kg) 600

Total manganese content (mg/kg) 20

OBP absorption value 2.04

Claims

1, a kind of producing and manufacturing technique that extracts silicon-dioxide is with rice hull ash, and Boiler Ash is a raw material, the invention is characterized in:

A. utilize rice hull ash, Boiler Ash is 140-170 ℃ in temperature, and reaction pressure is 5-7MPa, and the reaction times is under 4-5 hour the condition, to carry out chemical reaction with soda ash solution in stirred autoclave;

B. liquid is carried out the first time with chamber filter press and filter, to 20-22 ℃, filtrate has the gluey precipitation of a large amount of silicon-dioxide to separate out in process of cooling and yellow soda ash decomposes out through the water cooler fast cooling for filtrate;

C. yellow soda ash that decomposites and the silicon-dioxide of separating out are carried out the filtration second time, and then the silicon-dioxide in the chamber filter press is filtered, the clear water washing is to neutral;

D. the silicon-dioxide in the chamber filter press is taken out, pull an oar through defibrination, after the acid neutralization, precipitate 8 hours, filter with chamber filter press for the third time, remove salt solution, in the hot-air flow drying system more than 300 ℃, dry, can obtain more than 325 orders senior superfine active silicon-dioxide of following two kinds of 325 orders;

E. with above-mentioned D or the senior superfine active silicon-dioxide of two kinds of kinds, can obtain the silica product that replaces vapor phase process to produce 800-1000 ℃ of sintering oven oven dry.