RU2734574C1 - Method of charge preparation for colorless glass melting in glass containers production - Google Patents

Abstract

FIELD: technological processes.

SUBSTANCE: invention relates to methods of making charge in glass industry. Charge is obtained by dosing, mixing and moistening in a mixer of quartz sand, soda ash and other glass-forming components, as well as additives in form of a premix of selenium and cobalt oxide with filler. In the process of mixing, in amount of 3-4 % of the weight of the prepared charge portion, sodium silicate block with a silica modulus of 2.6-3.0 is pre-ground and classified into granulometric composition to 0-10 mm. Part of granules classified by granulometric composition of sodium silicate with fraction from 0 mm to 2 mm, which is part of fraction 0-10 mm, prior to loading charge is mixed in amount of 0.6-1.2 % of weight of prepared portion of charge with specified portion of additive in form of premix of selenium and cobalt oxide with filler and loaded into mixer of charge upon completion of supply to it of 40-50 % of calcined soda. Other part of granular blocks-lumps classified as granulometric composition with fraction from 2 mm to 10 mm, which is part of fraction 0-10 mm, in amount of 2.1-3.2 % of weight of the prepared portion of charge is supplied to mixer of charge for 20-30 seconds prior to unloading the prepared portion of charge therefrom. Amount of quartz sand and calcined soda in the mixture is reduced by 2.15-2.95 % and 0.77-1.13 % of the weight of the prepared portion of the charge, respectively.

EFFECT: intensified process of glass making and reduced degree of volatilation.

1 cl, 1 dwg

Description

The technical solution relates to the glass industry and can be used for melting colorless glass in the production of glass containers.

Usually, for melting colorless glass, a charge is prepared consisting of quartz sand, soda ash, dolomite, limestone, feldspar, sodium sulfate and, in some cases, nitrate, as well as physical and chemical bleaching additives based on selenium, cobalt and cerium oxides and other raw materials. ... At the same time, to increase the intensification of the glass-making process and increase the productivity of the glass-melting furnace, various methods are used, associated with grinding and mechanical activation of individual components of the charge, compaction and granulation of the raw mixture, replacement of one of the components of the charge with a chemically more active material, increasing the percentage of cullet, electric heating of the glass melt and etc. However, in industrial glass making, most of these methods are not used due to their laboriousness and high price of the equipment required for this (except for electric heating and increased glass cullet content).

Replacement of a part of sodium carbonates in the charge with sodium hydroxide (NaOH) solution is also practically not used, which significantly accelerates the process of silicate formation in glass, but is not used because of the high (compared to soda ash) price and significant complication of the technology for preparing the charge and glass melting. For the same reason, the use of liquid soluble glass (sodium silicate) is limited [1].

As a rule, the productivity of a glass-melting furnace is set when designing a heating unit and is determined by its design parameters. An additional increase in this productivity can be achieved during the operation of the furnace or by increasing the amount of cullet used, which (especially imported) for the production of colorless glass containers is almost always not enough, either by installing additional electric heating in the melting basin, or by increasing the temperature in the furnace. But imported cullet used for melting colorless glass often does not correspond in its chemical composition to the given glass composition. Moreover, there are situations when in the glassmaking process only its own technological cullet is used, the content of which does not exceed 10-12% during stable operation of the furnace. In these cases (especially if the furnace is already equipped with electric heating) there are no reserves for increasing the furnace productivity, and an increase of 10-15% is necessary, for example, when modernizing glass-forming machines, the previous productivity of which corresponded to the lower design capacity of the glass-melting furnace, taking into account electric heating.

It should be noted that during the approach of a cold repair, the cooking capacity of the furnace decreases. At the same time, if electric heating of molten glass was initially used in the design of the furnace, there is no reserve for increasing productivity to the nominal value during this period of operation. The use for these purposes of a higher temperature in the gas-flame space of the glass-melting furnace can restore the required productivity of the glass melting process, but will lead to a significant reduction in the service life of the refractory masonry and the furnace campaign.

An important technological aspect in the melting of colorless glass in the production of glass containers is the discoloration of the molten glass. The most common physical bleaching agents used for these purposes are cobalt oxide and expensive selenium, a significant part of which volatilizes during glass melting, which initially requires an overestimated (in excess of the required) dose of this component to be fed into the charge.

There are various ways to reduce such losses of selenium [2,3] associated with its volatilization. In accordance with some of these methods, selenium is pre-mixed with liquid glass, and the viscous mixture is either calcined in a microwave oven to obtain a frit, or made from non-granules, which are then dried in special ovens. It is obvious that all these operations, associated with the use of liquid glass, which is a viscous liquid, significantly complicate the process of dosing and preparation of the charge and require special, not commercially available equipment.

In this regard, of interest are methods for preparing a charge and melting glass, taking into account not only the possibility of intensifying the glass-making process, but also saving such an expensive raw material as selenium.

A known method of preparing a charge used for cooking colorless and colored iron-containing glasses [4]. In this method, the charge is prepared only from cullet containing mainly two fractions of glass particles 15 - 75 mm and 0.5 - 5 mm. Moreover, the fine fraction of cullet in the amount of 5 - 40% of the total mass of the prepared mixture is pre-moistened with water and corrective and modifying additives are introduced into it, for example, glass melt decolorizers. Coarse fraction and a mixture of fine fraction with additives are loaded into the hopper of a glass-making furnace in layers. The disadvantage of this method is its limited use for melting colorless glass in large-capacity (up to 300 tons of molten glass per day) furnaces, which is due to the complexity of collecting the required amount of high-quality colorless cullet. It is also difficult to determine the amount of decolorizing additives introduced into cullet, which has a heterogeneous chemical composition. And given the fact that additives are introduced into the cullet layer by layer and are unevenly distributed in the mixture of dissimilar cullet, it is almost impossible to weld chemically homogeneous colorless glass mass from such a mixture. In this regard, this method can only be used for cooking green glass. There are no reserves in this method for increasing the productivity of a glass-melting furnace using only a glass-breaking mixture for glass melting.

A more uniform distribution of bleaching additives is achieved in the method of preparing a glass batch [5], which includes a metered supply of free-flowing components to the mixer and their moistening, alternate feeding of clumping components into the mixer, and after reaching the nominal value of the mixture, the bleaching additives are introduced into it. This method of preparing the charge allows you to improve the quality of mixing the mixture and obtain a more uniform distribution of additives throughout the volume of the mixture. But in the mixture prepared at the same time, volatilization of selenium during its cooking in a glass furnace is not excluded. Also, this method of preparing the charge does not allow to intensify the glass-making process with the required increase in the furnace productivity.

As already noted, the glassmaking process can be significantly intensified by introducing either sodium hydroxide or liquid glass into the charge, but the first of these materials is chemically aggressive, and the second requires a more complex technology for dosing and preparing the charge, the adhesion properties of which increase. The charge prepared using liquid glass adheres more actively to the walls of mixers and hoppers, which makes it difficult to use it in traditional batching and mixing lines. Therefore, it is of interest to use, for the preparation of a glass batch, not liquid glass produced from a silicate lump, but directly the silicate lump itself, which is a lump material.

The closest technical solution using lump silicate in the process of preparing a glass batch is a method for preparing a glass batch [6], which includes dosed supply and mixing of glass-forming components, lump silicate and additives in a mixer. The use of lump silicate in the charge prepared by this method allows intensifying the glass-making process. However, a significant disadvantage of this method is the use of expensive sodium hydroxide used for the preparation of lump silicate and the complexity of the technological process, the implementation of which was carried out only in laboratory conditions. This method also lacks a technique for the optimal introduction of additives into the composition of the charge.

The problem being solved is to increase the intensification of the glass-making process and reduce the degree of volatilization of selenium during the melting of colorless glass in the production of glass containers.

This technical result is achieved by the fact that in the method for preparing a charge for melting colorless glass in the production of glass containers, including the dosed supply of quartz sand, soda ash and other glass-forming components, as well as lump silicate and additives in the form of a premix of selenium and cobalt oxide with filler, and subsequent mixing and moistening of the materials loaded into the mixer, in the process of mixing the loaded materials into the mixer, add in an amount of 3-4% of the mass of the prepared portion of the charge, preliminarily crushed and classified according to the particle size distribution to a fraction of 0-10 mm, sodium silicate - a lump with silicate module 2.6 - 3.0. Moreover, a part of a sodium silicate lump classified by particle size distribution with a fraction from 0 mm to 2 mm, which is part of a fraction of 0 - 10 mm, is mixed in an amount of 0.6 - 1.2% of the mass of the prepared batch of the charge with with a predetermined portion of the additive in the form of a premix of selenium and cobalt oxide with a filler and loaded into the batch mixer at the end of feeding 40-50% of soda ash into it. And the other part of the silicate-lumps classified according to the granulometric composition with a fraction from 2 mm to 10 mm, included in the fraction 0 - 10 mm, in an amount of 2.1 - 3.2% of the mass of the prepared batch of the charge is fed into the charge mixer for 20 30 seconds before unloading the prepared portion of the charge from it, while the amount of quartz sand and soda ash in the charge is reduced by 2.15-2.95% and 0.77-1.13%, respectively, of the mass of the prepared portion of the charge.

The advantage of the proposed method for preparing a charge for melting colorless glass in the production of glass containers is the use of lumpy lump silicate, which is preliminarily crushed and classified according to the granulometric composition, in an amount of 3-4% of the weight of the batch of the charge being prepared. The use of such a quantity of lump silicate in the composition of the glass batch allows to intensify the glass-making process and increase the capacity of the glass-melting furnace, and, consequently, the productivity of the glass container production lines by 8-10%. When this batch is boiled in a glass-making furnace with a capacity of 240-300 tons of glass melt per day, it really becomes possible to increase the daily glass removal by 19.2-30.0 tons, which in terms of a glass bottle in a 0.5-liter version (the average weight of a bottle is taken 330 grams) is 58 - 91 thousand bottles per day or 21 - 33 million units of glass containers per year. Also, if an increase in the nominal (design) power of the glass-making furnace is not required, as is required when using modernized and more efficient glass-forming machines, it is possible to maintain the power of the furnace (without an inevitable decrease) at the end of its campaign without increasing the glass melting temperature and increasing fuel consumption. At the same time, an increase in the power of a glass-making furnace due to the introduction of lump silicate into the charge composition in both cases in excess of 8-10% is economically impractical, since the cost of this additive in terms of the cost of the equivalent mass of soda exceeds it by about 3 times.

Another advantage is that preliminary (before loading into the mixer) mixing of a part of a lump silicate lump crushed to a fraction of 0 mm to 2 mm with an additive in the form of a premix based on selenium, cobalt oxide and a filler allows for a more even distribution of the additive in the volume of the prepared mixture ... This is due to the fact that the mass of the mixture of crushed lump silicate of the fraction from 0 mm to 2 mm with a premix of selenium, cobalt oxide and filler is approximately 0.6 - 1.2% of the mass of the prepared batch of the charge, which is 12-18 times more the mass of only one premix, the mass of which usually does not exceed 300-500 grams.

Another advantage of the proposed method for preparing a glass batch is that selenium particles in a mixture with lump silicate particles fall into the mixer during feeding to soda, which is a more low-melting component, which to a certain extent promotes faster melting of selenium and reduces its percentage volatilization. The volatilization of selenium is also reduced due to the fact that of all the components of the charge, including cullet, the lump silicate melts at a temperature of about 600 ° C, which is about 100 ° C below the melting point of the cullet. Therefore, at lower temperatures, selenium particles are enveloped by the primary melt of lump silicate and soda, which reduces the percentage of volatilization of selenium in the silicate formation zone of the glass furnace by about 10-12%.

An important technological aspect is the fact that, unlike the prototype, in which a lump silicate prepared using a complex technology has the consistency of a suspension sifted through a 0.04 sieve, 70 - 80% of the crushed lump silicate used in the proposed method has a particle size of 2 mm up to 10 mm. Small particles of lump silicate, as well as small particles of cullet melt faster than other components in the charge and interact with soda. If, in this case, the entire volume of the silicate lump, fed together with the charge into the furnace, is crushed to a fraction from 0 mm to 2 mm or less, as in the prototype, the fast melting rate of fine particles will interfere with the normal process of silicate formation and clarification of the molten glass. Larger fragments of silicate lumps melt gradually, forming centers of formation of primary melts around themselves in the furnace cooking zone (by analogy with the formation of such centers around cullet particles having a size of 20-30 mm), which is more favorable for the entire glassmaking process.

Since in this method a not very coarse fraction from 2 mm to 10 mm of crushed and classified lump silicate is introduced into the mixture, it can be fed directly into the mixer at the end of mixing the entire mixture, which will undoubtedly increase the uniformity of its distribution over the mixture. Since lump silicate particles ranging in size from 2 mm to 10 mm will be in the mixer for only 20 - 30 seconds, their abrasive effect on the working bodies and walls of the mixing apparatus is minimized. In turn, a more uniform distribution of the crushed lump silicate throughout the volume of the mixture, along with other noted factors, also contributes to the production of a more homogeneous glass melt and intensifies the glass-making process.

Obviously, when used as an intensifying additive, lump silicate with a silicate module of 2.6 - 3.0, consisting of 71.7 - 73.8% of silicon dioxide (quartz sand) and 25.5 - 28.2% from sodium oxide (soda ash) [7], the amount of the corresponding components in the charge can be reduced.

The process of preparing a charge for melting colorless glass in the production of glass containers is implemented using a dosing and mixing line (figure 1), which includes: a supply bin 1 of quartz sand; supply hopper 2 soda ash; supply bins for 3 other glass-forming components; the corresponding strain gauge weighing batchers 4, 5, 6; assembly conveyor 7; mixer 8 of the charge with a system 9 for wetting the charge; receiving hopper 10 of the batch mixer, equipped with a vibrating feeder 11 unloading; line 12 for transporting the charge to the glass furnace.

Big-bags 13 with a lump silicate having a small-sized (50 - 100 mm) fractional composition are fed by means of a crane-beam 14 to the unloading position in an intermediate hopper 15. From this silo, the lump silicate is loaded by a vibrating feeder 16 into a hammer crusher 17, where is crushed. Further, the crushed lump silicate is transported by a belt bucket elevator 18 and sent to a screen 19, where it is divided into three fractions with the help of two nets having a corresponding mesh size. Lump silicate particles with a size of more than 10 mm (oversize product of the upper mesh) are thrown into a hammer mill 17 for additional crushing. The undersize product of the upper mesh having a fractional composition of 0-10 mm is fed to the lower mesh and is divided into two working fractions on it. The oversize product of the lower mesh, having a particle size of 2 mm to 10 mm, is discharged into the feed hopper 20, equipped with a strain gauge weighing meter 21, and the undersize product with a particle size of silicate lumps from 0 mm to 2 mm is sent to the feed hopper 22, equipped with a strain gauge weighing machine 23.

The premix (premix) of selenium, cobalt oxide and filler, which can be soda ash or quartz sand, is stored in the feed hopper 24, equipped with a corresponding strain gauge weighing meter 25. Since the consumption of the premix is small (200-300 g per 1 - 1.5 tons of charge), it is often prepared in a separate area either manually or using an automated dosing and mixing complex [8] (not shown in the diagram). The premix from the outlet of the strain gauge weighing batcher 25 is fed into the intermediate mixer 26, where it is mixed with a silicate lump with a particle fraction from 0 mm to 2 mm, which is loaded into this mixer from the strain gauge weight batcher 23. The volume of the intermediate mixer 26 depends on the mass of the batch of charge prepared (varies from 750 kg to 4500 kg) and can be 10-100 liters.

The line works as follows. Quartz sand, soda ash, and other glass-forming components, as well as a premix of selenium and cobalt oxide with a filler, crushed lump silicate with a particle fraction from 0 mm to 2 are preliminarily loaded into feed bins 1, 2, 3, 24, 22, 20. mm and crushed lump silicate with a particle fraction from 2 mm to 10 mm. At the command of the control system (not shown), strain gauge weighing 4, 5, 6, 25, 23, 21, located under these bins, weigh the prescribed dose of the above materials.

The choice of the value of the weight doses of crushed lump silicate of both fractions is determined based on the total amount of lump silicate (3-4% of the mass of the prepared batch of the charge) and the number of fractions with a particle size from 0 mm to 2 mm and from 2 mm to 10 mm. Usually, when crushing small-sized silicate - lumps in a hammer crusher and subsequent classification on a two-sieve screen with a maximum hole size on the upper mesh of 10-11 mm, approximately 20-30% of the fine fraction (from 0 mm to 2 mm) and 70-80% of the coarse fraction are obtained. fractions (from 2 mm to 10 mm). Moreover, the percentage of both fractions can vary within the specified limits, depending on the regulation in the crusher of the gaps between the hammers and the baffle plate (grate).

The choice of the total amount of lump silicate introduced into the charge is determined, firstly, from the economic feasibility (with a larger (more than 3-4%) percentage, the cost of the charge and the welded glass melt increases), and secondly, a larger amount of lump silicate introduced for due to its rapid melting, as practice has shown, it complicates the process of clarifying the molten glass. In addition, with an increased (more than 3-4%) content of lump silicate in the charge, it leads to an increased content of iron oxides in the glass, and therefore requires a larger amount of physical decolorizers of the glass melt based on selenium and cobalt oxide. This, in turn, minimizes the effect of reducing the volatilization of selenium when enveloping its particles with a melt formed from small particles of silicate lumps. At the same time, the increased content of iron oxides in the lump silicate is due to the fact that it is usually boiled from quartz sand containing 0.1 - 0.15% iron oxides, while for melting high-quality colorless glass, a higher quality quartz sand with an iron content of not more than 0.03-0.04%.

After a set of predetermined doses of these materials, which are part of the prepared charge, and the preparation of a mixture of the premix with a fraction of silicate lumps of 0 - 2 mm in the intermediate mixer 26, the control system (not shown) generates a signal to turn on the mixer 8 of the charge and the assembly conveyor 7, as well as gives permission for unloading strain gauge weighing batchers. The unloaded raw materials are transported by an assembly conveyor 7, from the outlet of which they enter the batch mixer 8. Strain gauge weighing batcher 4 of quartz sand is unloaded first. After 10-15 seconds on quartz sand in the mixer 8 of the charge is sprayed with water coming from the system 9 for wetting the charge. At the end of the unloading and moistening of quartz sand, a command is formed to unload and feed the soda ash charge into the mixer 8 (this generally accepted unloading procedure eliminates soda clumping).

As 40 - 50% of soda ash entering the batch mixer from the strain gauge weighing meter 5 is unloaded, a mixture of selenium premix and cobalt oxide is fed from the intermediate mixer 26 to the batch mixer 8 with a given dose of lump silicate, having a particle size distribution from 0 mm to 2 mm. The mixture of the premix and lump silicate with the specified particle size begins to be evenly distributed throughout the mixer during the mixing process of the moist quartz sand and soda ash. At the same time, selenium particles are evenly distributed among small particles of lump silicate and soda ash, which during subsequent glass melting from such a mixture leads to enveloping of selenium particles (usually metal selenium with a particle size of no more than 2 mm is used) with a melt of lump silicate and soda, which slows down the process of volatilization of this expensive material. This is also facilitated by the onset of solid-phase reactions of a fine fraction (from 0 to 2 mm) of silicate lumps with moistened soda, in which selenium is evenly distributed, which is a consequence of the partial surface dissolution of crushed silicate lumps by water due to the high hygroscopicity of this material.

Upon completion of the unloading of soda ash and other glass-forming components of the charge from the strain gauge weighing feeders 6 in the control system of the dosing and mixing line, the time for mixing the charge begins (usually this time is 2-3 minutes). And 20-30 seconds before the completion of this operation, a command is formed to unload the strain gauge weighing meter 21, from which a lump silicate with a particle fraction of 2 mm to 10 mm is sent to the batch mixer 8. At the end of this time, during which 70 - 80% of the crushed silicate lumps with particles of 2 - 10 mm are evenly distributed in the raw mixture, the prepared mixture is discharged from the mixer into the receiving hopper 10. Then the mixture is poured onto the belt using a vibrating feeder 11. conveyor line 12 for transporting it to a glass furnace (not shown).

Let us calculate the percentage of each fraction of lump silicate in a portion of the prepared charge, taking into account that the total optimal amount of lump silicate loaded into the mixer is 3-4%. The calculation will be carried out for a portion of the charge, the mass of which is 1000 kg (with a greater or lesser mass of the prepared portion of the charge, the calculated data are multiplied by proportional decreasing or increasing factors). As already noted, when crushing a lumpy silicate lump in a hammer mill, 20 - 30% of a fraction with a particle size of 0 mm to 2 mm and 70 - 80% of a fraction with a particle size of 2 mm to 10 mm are formed.

3-4% (the total mass of the lump silicate added to the composition) for a batch of 1000 kg is 30-40 kg. Of these, 20-30% or (6-8 kg) - (9-12) kg is a lump silicate with a particle size of 0 mm to 2 mm. The overall mass range for this fraction is 6-12 kg or 0.6-1.2%.

70 - 80% in the composition of 30 - 40 kg, or (21-28 kg) - (24-32 kg) - this is a part of the silicate lump introduced into the charge with a particle size of 2 mm to 10 mm. Accordingly, the total mass range for this fraction is 21-32 kg or 2.1-3.2%.

According to GOST R 50418 - 92 soluble sodium silicate with a silicate modulus 2.6 - 3.0 (the ratio of the mass fraction of silicon dioxide in% to the mass fraction of sodium oxide in%, multiplied by the coefficient k = 1.023) contains 71.7 - 73.8% silicon dioxide (quartz sand) and 25.5 - 28.2% sodium oxide (soda ash). Therefore, 30 kg of lump silicate contains 30 kg (71.7 - 73.8)% = 21.51 - 22.14 kg, and 40 kg of lump silicate contains 40 kg (71.7 - 73.8) % = 28.68 - 29.52 kg of silicon dioxide. That is, the total range of silicon dioxide content in a portion of lump silicate weighing 30 - 40 kg is 21.51 - 29.52 kg or 2.15 - 2.95% of the total mass (1000 kg in this example) of the prepared mixture. By this amount, with the appropriate introduction of lump silicate into the mixture, it is necessary to reduce the content of quartz sand in order to preserve the original recipe and the chemical composition of the glass.

30 kg of lump silicate contains 30 kg (25.5 - 28.2)% = 7.65 - 8.46 kg, and 40 kg of lump silicate contains 40 kg (25.5 - 28.2)% = 10.2 - 11.3 kg sodium oxide. The total range of change in the amount of sodium oxide in a portion of lump silicate weighing 30-40 kg is in the range of 7.65 - 11.3 kg or 0.77-1.13% of the total mass of the prepared mixture. Obviously, it is necessary to reduce the content of soda ash in the charge by the same amount in order to maintain the given recipe for the raw material mixture and the chemical composition of the glass.

Let us consider several examples of the implementation of this method of preparing a charge for melting colorless glass in glass furnaces with a capacity of 240 - 300 tons of glass per day for the production of glass containers.

Example 1.

The initial charge for melting colorless glass contains the following components:

Quartz sand - 55%;

Soda ash - 19.3%;

Dolomite - 14.1%;

Limestone - 5.5%;

Feldspar - 5.3%;

Sodium sulfate - 0.57%;

Coal - 0.04%;

Premix (selenium, cobalt oxide, filler) - 0.02 ÷ 0.025%

Total - 100%.

The batch is cooked in a glass furnace with a capacity of 240 tons of glass per day. To increase the intensification of the glass-making process and increase the removal of molten glass, 3% (of the mass of the prepared batch of the charge) of a crushed and granulometric-graded silicate lump with a silicate modulus 2.6, containing 20% of the fraction from 0 mm to 2 mm and 80% fractions from 2 mm to 10 mm. With a silicate module of 2.6, the silicate lump contains 28.2% sodium oxide (soda ash) and 71.7% silicon dioxide (quartz sand), which of the total mass of the prepared batch of charge is 3% × 28.2% = 0.85% sodium oxide and 3% × 71.7% = 2.15% silicon dioxide. Accordingly, the charge recipe is adjusted to these values after adding lump silicate to it:

Quartz sand - (55% - 2.15%) = 52.85%;

Soda ash - (19.3% - 0.85%) = 18.45%;

Dolomite - 14.1%;

Limestone - 5.5%;

Feldspar - 5.3%;

Sodium sulfate - 0.57%;

Coal - 0.04%;

Premix (selenium, cobalt oxide, filler) - 0.02 ÷ 0.025%

Lump silicate with fraction from 0 mm to 2 mm - (3% × 20%) = 0.6%;

Lump silicate with a fraction of 2 mm to 10 mm - (3% × 80%) = 2.4%.

Total - 100%.

The charge is prepared in a mixer with a capacity of 1500 liters (the volume of the mixer, depending on the required performance, can vary from 750 l to 4500 l). The mass of the prepared batch of the charge is 1200 kg. For this value, the amount of lump-silicate introduced into the raw mixture is 1200 kg × 3% = 36 kg. Of these 36 kg, 7.2 kg (20% is a silicate lump with a fraction from 0 mm to 2 mm, which is mixed in an intermediate mixer with a premix of selenium and cobalt oxide with a filler before being loaded into the batch mixer. The weight of the premix is 1200 kg × 0.02% = 0.24 kg. To mix this amount of premix with 7.2 kg of crushed lump silicate, an intermediate mixer with a volume of 10 liters is required. 28.8 kg (80% of 36 kg) lump silicate with a fraction of 2 mm or more up to 10 mm is loaded directly into the batch mixer.

The amount of quartz sand loaded into the mixer is reduced by 1200 kg × 2.15% = 25.8 kg, and soda by 1200 kg × 0.85% = 10.2 kg.

When a batch is cooked with the addition of 3% (based on the mass of the batch of batch being prepared) of crushed and granulometric lumped silicate, the removal of molten glass increases by 8% (19.2 tons) and, by about 10%, the consumption of selenium is reduced by reducing its volatilization from the zone of silicate formation (practically this is the zone of loading the charge) of the glass-making furnace.

If the total mass of the silicate lump is increased to 48 kg (4% of the mass of the prepared batch of 1200 kg), then the amount of quartz sand included in the batch of the batch loaded into the furnace decreases by 4% × 71.73% = 2 , 86% or 1200 kg × 2.86% = 34.3 kg. The amount of soda ash in the charge is also reduced by 4% × 28.2% = 1.13% or, in terms of kilograms, 1200 kg × 1.13% = 13.56 kg.

The productivity of the glass-melting furnace (removal of molten glass) increases by about 10%, which is 24 tons of glass per day. Selenium volatilization is reduced by 11-12%. This is the maximum possible increase in the removal of molten glass, which does not lead to an increase in the cost of both the charge and the glass. With a higher percentage of lump silicate, this condition (increase in cost) is not met.

It should be noted that the maximum effect of the introduction of lump silicate into the charge is achieved when its silicate modulus is 2.6, which is due to the maximum content of sodium oxide in the material used. But, naturally, the comparative price of such material will be maximum. Therefore, it is of interest to use lump silicate with a silicate modulus 2.9 - 3.0, which is also due to the fact that the largest Russian manufacturer of this product, the Salavatsteklo glass plant in Bashkiria, mainly produces lump silicate with a modulus of 2.9 ...

Example # 2.

The initial charge for melting colorless glass contains the same components as in example No. 1:

Quartz sand - 55%;

Soda ash - 19.3%;

Dolomite - 14.1%;

Limestone - 5.5%;

Feldspar - 5.3%;

Sodium sulfate - 0.57%;

Coal - 0.04%;

Premix (selenium, cobalt oxide, filler) - 0.02 ÷ 0.025%

Total - 100%.

The batch is cooked in a glass furnace with a capacity of 300 tons of glass per day. To increase the intensification of the glass-making process and increase the removal of molten glass, 4% (of the mass of the prepared batch of the charge) of crushed and granulometric-classified silicate lumps with a silicate modulus 2.9 containing 30% of the fraction from 0 mm to 2 mm and 70% is introduced into the charge fractions from 2 mm to 10 mm. With a silicate module of 2.9, the lump silicate contains approximately 26.4% sodium oxide (soda ash) and 73.2% silicon dioxide (quartz sand), which of the total mass of the prepared batch of the charge is 4% × 26.4% = 1.06% sodium oxide and 4% × 73.2% = 2.92% silicon dioxide. Accordingly, the charge recipe is adjusted to these values after adding lump silicate to it:

Quartz sand - (55% - 2.92%) = 52.08%;

Soda ash - (19.3% -1.06%) = 18.24%;

Dolomite - 14.1%;

Limestone - 5.5%;

Feldspar - 5.3%;

Sodium sulfate - 0.57%;

Coal - 0.04%;

Premix (selenium, cobalt oxide, filler) - 0.02 ÷ 0.025%

Lump silicate with a fraction of 0 mm to 2 mm - (4% × 30%) = 1.2%;

Lump silicate with a fraction of 2 mm to 10 mm - (4% × 70%) = 2.8%.

Total - 100%.

The charge is prepared in a mixer with a capacity of 2250 liters (the volume of the mixer, depending on the required performance, can vary from 750 l to 4500 l). The mass of the batch to be prepared is 2250 kg. For this value, the amount of lump-silicate introduced into the raw mixture is 2250 kg × 4% = 90 kg. Of these 90 kg, 27 kg (30% is a silicate lump with a fraction from 0 mm to 2 mm, which is mixed in an intermediate mixer with a premix of selenium and cobalt oxide with a filler before being loaded into the batch mixer. The weight of the premix is 2250 kg × 0, 02% = 0.45 kg. To mix this amount of premix with 27 kg of crushed lump silicate, an intermediate mixer with a volume of 30 liters is required. 63 kg (70% of 90 kg) lump silicate with a fraction of 2 mm to 10 mm is loaded directly into batch mixer 20-30 seconds before the end of the mixing cycle.

The amount of quartz sand loaded into the mixer is reduced by 2250 kg × 2.92% = 65.7 kg, and soda by 2250 kg × 1.06% = 23.9 kg.

When a batch is cooked with the addition of 4% (of the mass of the batch of batch being prepared) of crushed and classified according to the granulometric composition of silicate lumps, the removal of molten glass increases by 9% (27 tons) and, by about 10%, the consumption of selenium is reduced by reducing its volatilization from the zone silicate formation.

With a silicate modulus equal to 3.0, the indicators of increasing the efficiency of glass making are approximately the same. The amount of quartz sand in the prepared batch of the charge decreases by 2250 kg × 2.95% = 66.4 kg (2.95% = 4% × 73.8%, where 73.8% is the content of silicon dioxide in a silicate lump with a modulus = 3), and soda by 2250 kg × 1.02% = 22.95 kg (1.02% = 4% × 25.5%, where 25.5% is the content of sodium oxide in a silicate lump with modulus = 3 , 0).

Thus, the use of 3-4% crushed and classified by granulometric composition silicate lumps with a silicate modulus of 2.6 - 3.0 in the glass batch for melting colorless glass in the production of glass containers can increase the productivity of the glass furnace by 8-10% and reduce loss of selenium due to its volatilization by 10 - 12%. All the above indicators of increasing the efficiency of glass making were obtained in the process of real glass melting at operating glass container plants.

Sources of information that you should pay attention to during the examination:

1. Glass technology. Ed. I.I. Kitaygorodsky. Stroyizdat. M. 1961.S. 334, 336-351.

2. Polkan G.A., Pentko V.L., Yanakidi E.V. and others. Development of effective methods for the preparation and introduction of dyes into the charge // "Stekloprogress - XXI" Coll. scientific reports. - Saratov, LLC "Bukva". 2013.S. 31-35.

3. RF patent for invention №2551540. A method of preparing a glass batch for melting heat-absorbing bronze glass. V.V. Efremenkov. Publ. 05/27/2015. Bull. No. 15.

4. RF patent for invention №2250879. A method of melting colorless and colored iron-containing glasses from broken glass. D.V. Kondrashev. Publ. 27.04.2005. Bull. No. 12.

5. RF patent for invention №2115632. A method for preparing a glass batch. V.V. Efremenkov, B.C. Rozhkov, V.N. Berezin, et al. Publ. 20.07.1998. Bull. No. 20.

6. RF patent for invention No. 2053970. A method for preparing a glass batch. A.I. Vezentsev. Publ. 02/10/1996. Bull. No. 4.

7. GOST R 50418 - 92. Soluble sodium silicate. Technical conditions.

8. V.E. Manevich, K. Yu. Subbotin, V.V. Efremenkov. Raw materials, charge and glass making. M. RIF "BUILDING MATERIALS". 2008.224 p.

Claims (1)

A method of preparing a charge for melting colorless glass in the production of glass containers, including dosed feeding into a mixer of quartz sand, soda ash and other glass-forming components, as well as lump silicate and additives in the form of a premix of selenium and cobalt oxide with a filler and subsequent mixing and moistening loaded into mixer of materials, characterized in that during the mixing of the loaded materials, a sodium silicate lump with a silicate modulus of 2,6 is added to the mixer in an amount of 3-4% of the mass of the prepared portion of the charge, which is preliminarily crushed and classified according to the granulometric composition to a fraction of 0-10 mm. 3.0, moreover, a part of a sodium silicate lump classified by particle size distribution with a fraction from 0 mm to 2 mm, included in the fraction 0-10 mm, is mixed in an amount of 0.6-1.2% by weight before loading into the mixer the prepared portion of the charge with a given portion of the additive in the form of a premix of selenium and cobalt oxide with a filler and loaded into a batch mixer at the end of feeding 40-50% of soda ash into it, and a part of silicate-lumps classified according to the granulometric composition with a fraction from 2 mm to 10 mm, included in the fraction 0-10 mm, in the amount of 2, 1-3.2% of the mass of the prepared batch of the charge is fed into the batch mixer 20-30 seconds before unloading the prepared batch of the batch from it, while the amount of quartz sand and soda ash in the batch is reduced by 2.15-2.95%, respectively, and 0.77-1.13% of the mass of the prepared batch of the charge.

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