RU2156222C1 - Method of manufacturing agglomerated silicate - Google Patents

Abstract

FIELD: glassmaking. SUBSTANCE: agglomerated silicate is prepared by crushing silicon- containing material, in particular glass scrap, followed by melting it with soda under ore-thermal conditions at glass scrap-to-soda weight ratio (10- 15):1. Glass melt is then granulated to give desired product. EFFECT: simplified technology.

Description

 The invention relates to chemical technology, in particular to the production of "silicate blocks" used in the production of liquid glass.

A known method of preparing a "silicate block" for a glass mixture, characterized in that the "silicate block" is obtained by grinding quartz sand in a 45% aqueous NaOH solution before passing the suspension through a 0.04 sieve, followed by autoclaving the resulting suspension 120-250 ^o C and an excess pressure of 2-80 atm and drying at 300-400 ^o C [1].

 The disadvantages of this method are the high consumption of sodium alkali (up to 40% wt.), High energy consumption and technical complexity of the process.

 There is a method adopted for the prototype of obtaining a "silicate block" by cooking a mixture consisting of quartz sand and soda (sodium carbonate) in a glass melting furnace [2].

In the known method, the interaction of silicon dioxide (silica) with sodium oxide is carried out at a temperature of 1450-1500 ^o C for 6-8 hours

 The disadvantages of this method are the high consumption of soda (up to 50% wt.), High energy consumption for the reaction of interaction of silicon dioxide with sodium oxide and a significant yield of carbon dioxide.

 It is known that in household and industrial waste there is a huge amount of non-standard glass scrap (cullet) containing oxide impurities that do not allow its use in glass melting, which leads to the need for careful sorting of cullet by chemical composition (color).

 It is also known that the chemical composition of glass (cullet) includes silicon dioxide (silica) and sodium oxide, and the amount of sodium oxide in the glass is only slightly less than it should be in the "silicate block".

 The objective of the invention is technically simple and inexpensive to obtain a "silicate block".

 The specified technical result is achieved by the fact that in the method of producing a "silicate block", including crushing and smelting silica-containing material with soda, according to the invention, cullet is used as a silica-containing material, smelting is carried out in an ore-thermal mode with a ratio of cullet mass and soda mass (10-15 ): 1, after which the melt is granulated to obtain a "silicate block".

 The method is as follows.

Sodium carbonate (technical soda) is melted into the ore-thermal furnace equipped with graphite electrodes, which has a bathtub, which is a water-cooled metal casing with the possibility of a skull on the inner walls of the bathtub, equipped with a tap hole that allows periodically draining the melt with a cut-off in the furnace of its part. the arc mode and in the ore-thermal mode is brought to a liquid state with a melt temperature of 950-1150 ^o C.

A portion of crushed glass scrap, comprising not more than 1/3 of the mass of the initial sodium carbonate, is loaded into the melt and boiled until a melt of uniform consistency is obtained. This increases the viscosity of the melt and its resistance. To maintain the fluidity of the melt, its temperature is increased by increasing the voltage at the electrodes. The operation of loading glass scrap is repeated until the desired sodium silicate melt module is reached. The temperature of the melt at the end of the cycle reaches 1300-1400 ^o C. Then the resulting melt is discharged through the outlet with the leaving in the furnace part of the melt into which a new portion of sodium carbonate is loaded and the whole cycle is repeated.

 An example implementation of the proposed method.

 Obtaining silicate blocks with a module of 2.45-2.55.

Processing was subjected to cullet of the following chemical composition,%: SiO ₂ -74.4; Na ₂ O-24.4; CaO-4.2. To obtain a silicate block with a given module (calcium oxide is taken as a neutral component), it was necessary to increase the Na ₂ O content in the initial glass scrap by 4.25%, which in terms of sodium carbonate is 7.22% Na ₂ CO ₃ relative to the mass initial cullet.

In a two-electrode ore-thermal furnace with a capacity of 75 kVA, which allows loading up to 100 kg of charge materials, 7.5 kg of sodium carbonate were loaded, it was melted and the melt was heated to a temperature of 1100-1150 ^o C. Then 2.5 kg of glass scrap with a processing size of less than 20 mm and the resulting mixture was cooked for 15 minutes until a melt of uniform consistency was obtained. After that, the voltage at the electrodes was increased by 20% and 3.5 kg of cullet were loaded. The loading of cullet, its boiling until a homogeneous mixture is obtained, and the subsequent increase in voltage at the electrodes was repeated until 100 kg of cullet were boiled. The bulk of the obtained melt in an amount of 100 kg was poured through the outlet of the furnace, 7.5 kg of sodium carbonate was charged into the remaining melt in the furnace, and the whole cycle was repeated again.

The resulting silicate block had the following chemical composition%: SiO ₂ -68.7; Na ₂ O-27.3; CaO-4.0, which corresponds to a module of 2.52. The time taken to prepare 100 kg of “silicate block” was 3.5 hours.

 Thus, according to the proposed method, it is possible to carry out quick, inexpensive and technically uncomplicated production of a "silicate block", while utilizing any required amount of non-standard cullet.

Sources of information taken into account during the examination:
1. Pat. RF N 2053970 by application N 92014433/33 of 12/23/92, publ. Bull. fig. N 4, 02/10/96. MKI C 03 C 6/02, C 03 V 1/02.

 2. Ed. I.I. Kitaygorodsky. "Technology of glass", M.: Stroyizdat, 1961. S. 324.336-351 (Prototype).

Claims (1)

 A method of producing a "silicate block", including crushing and smelting silica-containing material with soda, characterized in that cullet is used as silica-containing material, smelting is carried out in the ore-thermal mode with a ratio of cullet mass to soda mass (10 - 15): 1, after which the melt is granulated to obtain a "silicate block".