DE2040385C3 - Process for the production of glass raw material batches in the form of small squares - Google Patents

Description

ioden granulated and the biscuits obtained dry at temperatures of 50 to 200 C and jhHeßlich bti temperatures below 500 C.

When using the manufactured according to the invention raw material pellets for glass production is the Gc-, chwindigkek of the ablating and Läuierungsvorlanges increased significantly, this results in a longer melting time, so that the amount of gas that can be worked out in a given time. is increased. The pellets range in size from 4 to TO mm (coarsest diameter), their breaking strength s> i very high and they are easy to handle.

Preferably, in the process of the invention, glass raw materials with an average grain size of less than ASTM No. 60 (0.250 mm) are used, of which at least 70% of the grains are smaller than ASTM No. 100 (0.149 mm) and 70% of the quartz sand grains are smaller to ASTM No. JiXl Kino more. Crushing de glass raw materials offers; o no more significant advantages to justify the additional costs. The granulation of the raw glass materials, which are mainly made of Quar / .sanii. (- "on ash and limestone, is carried out in the usual orrichhingen. The dried products are then thoroughly mixed, preferably by a dry mixing process. The homogeneous mixture obtained is granulated the powdered glass raw materials in (currently from 12 to 20 percent by weight, preferably about 1 5 percent by weight water (IS parts water per IfK) parts glass raw materials) in a conventional device, e.g. a roller or tumble mixer, granulated and agglomerated. Within this critical moisture range enoigi the agglomeration of the particles with the formation of rounded, compact and well-adhering pellets in the specified size range of about 4 to 20 mm and good handling properties. This result is practically impossible to achieve with a lower or higher water content.

The drying of the pellets obtained for Abi toning moisture must initially be moderate, i.e. above 50 C and less than half 200 C, preferably by means of 130 to 300 C hot gases, such as air. After this initial Drying, the cookies are dried further at temperatures below about 500 ° C. Drying temperatures Above about 500 C, the pellets will soften and stick to one another and are unsuitable for rapid glass production.

In the process of the invention, some or all of the sodium carbonate can be replaced with sodium hydroxide. Sodium hydroxide is preferred. calculated as Na ₂ O. in an amount of at least 20 percent by weight, based on the total mass, used. The sodium hydroxide can be used as a powder or as an aqueous solution. Part of the sodium hydroxide reacts with the limestone or calcium carbonate in the production of the pellets to form calcium hydroxide, while another part reacts with the quartz sand or the feldspar present as an impurity to form sodium silicate or sodium aluminate. Excess sodium hydroxide is carbonized during the production of the pellets, and no free sodium hydroxide remains. Preferably, the sodium hydroxide is added to the powdery glass raw material in the form of a 30 to 0 ^7% sodium hydroxide solution, and the granulation is preferably carried out at temperatures of at least H) OC. In this way it is possible to increase the proportion of sodium silicate formed. This has a favorable effect on the breaking strength and handling properties of the pellets obtained. The dried biscuits obtained are preferably sieved and the fraction with a diameter of 4 to 20 mm. especially 4 to 15mm. is used for glass production. The oversized pellets and the smaller pellets are reused in the process.

The following tests show the advantages associated with those produced according to the invention Pellets are obtained. The composition of the glass raw materials and the melting conditions are identical. A glass raw material mixture of the following composition was used for the experiments :

tieM; <ndicu J parts

Quartz sand! HX '

Sodium ; W.

Sodium hydroxide! P.5

Limestone i ~ 1

Sodium carbonate and limestone were ground much finer than usual and differently with quartz sand Mixed grain sizes. In experiment 1, powders of the usual grain size were mixed with one another and used and investigated in this form for glass production, since the mixture does not granulate well and let it deform into cookies. In Experiments 2 to 6, the mixture was in the presence of 12 to 20 parts of water per 100 parts of the mixture are granulated and shaped into cookies. In experiment 1 and 2 200 g of the powdery mixture and in experiments 3 to 6 200 g of the cookies were each in filled a crucible and gradually over 2 hours heated up to 500 C. The crucibles were then placed in an electric furnace at 14 (X) C and the time was determined until the mass was completely melted and no quartz sand residue was left more could be determined. The tests for the results are compiled in Table 1.

label!. · I

\ Cl Midi

nIW HeMui

1st, under 2.3X mm: about 15 ".
j below 0.144 now

isiehnl'f'mini ;. ιη: ιυ

1111L ν; ■ '\ Μ'ι nmr. about ^l ) "» under U. 14 ¹ J mm Ix-1 14m (". Muuik-n

l.rhcbbche Mertuen on the remaining quarter / saml
No remainder .i ^ Quur / .sanil

attempt
2
3.

Continued / unu grain size (sieve diameter. Mm)

all components

below 0.841 mm: et Aa 30%

below 0.149 mm below 0.42 mm: approx. 40%

under 0.149 mm under 0.42 mm: approx. 66%

below 0.149 mm below 0.42 mm: about 80%

below 0.149 mm below 0.42 mm: about 92%

less than 0.149 mm

Quar / sLind

below 0.841 mm: about 9%

below 0.149 mm below 0.42 mm: approx. 30%

below 0.149 mm below 0.250 mm; about 60%

below 0.149 mm and 0.177 mm: about 80%

below 0.149 mm below 0.14V mm

j Duration of exposure at 14 (H) C. minutes j 15 I 25 J 35 I 4i j -5 j 105 J 135 J 1 (ι5

y! ο

ο I ο

O! O

ο] ο

O: O

O! O

O 1

ο j t>

χ = Considerable amounts of remaining ljuarz sand \ = Small amounts of remaining quartz sand ο = no residue of quartz sand.

The exact sieve analysis is given in Tables II to VIl of the glass raw materials used in experiments 1 to 6. Sodium sulfate was in the form of common commercial product used.

Table 11 Experiment 1 grain sizes
ASTM No.

80 to 100

KX) up to 120

to 120

Quartz sand

I % I

8.0
4.9
4.0

sodium

17.2
54.8

Lime

Mitlloii-Komgrölx

13.2 j 9.9 10.4 j 7.5 67.7 22.0

Grain sizes
ASTM No.

Quartz sand

8 to

16 to

20 to

40 to

60 to

80 to 100

to 120

to 120

16
20th
40
60
80

0.2

38.8

32.8

11.3

8.0

4.9

4.0

83.1 I

sodium

... Jl ⁰ L-

1.4 40.9 27.3 13.7

5.8

3.6

7.3

limestone

("i.l

Middle grain

(•! ■ II I «' _

4.2

9.4

25.0

13.6

2.6

5.3

5.0

I 34.9

0.8

1.9

36.6

28.6

10.1

7.2

4.8

10.0

78

Remarks

The glass raw materials used in experiment 1 had the usual grain size distribution. The grain size was smaller than ASTM # 16 and 78% of the grains were larger than ASTM # 80, while 83.1% of the grains were Quartz sand grains were larger than ASTM No. 80. The mixture could not be granulated and turned into Peilets be deformed.

Table III Experiment 2

Remarks

In experiment 2 the sodium carbonate uiu the limestone further pulverized and with Qim> / sand of normal grain size mixed. The grain size. '^ were smaller than ASTM # 20 and 60.6% of the,:. All grains were larger than ASTM No. 80, but slightly smaller than the PuKer used in Experiment 1 This mixture could not be granulated either; and shape them into pellets.

Table IV Experiment 3

Q) uarzsand

Grain coarse
ASTM No.

16
20th
40
60

8 to

16 to

20 to

40 to

60 to 80

80 to 1 (X)

100 to 120

until ! 20th

0
0
0.6)

39.51

17.6)

12.7

11.8

17.8

57.7

sodium

0
0

0.4

3.8

8.6

15.2

17.2

54.8

limestone

0 0

0.3

14th

6.0

13.2

10.4

67.7

Medium

KomgroUi

I ¹ Oi

0 0

0.6 28.0 14.5 13.2 12.2 31.5

Grain sizes
ASTM No.

I quartz sand

("oil

8 to 16

16 to 20

20 to 40

40 to 60

60 to 80

0.2
38.8
32.8
11.3

83.1

Sodium carbonate

1 H ⁰ '

I ο

0.4 3.8 8.6

_; Kalk-I -.tem

i ί

! 0.3 i

i - ⁴

ί

Medium grain size

I)

0.1 27.1 23.5 10.0

60.6 Notes

In experiment 3, the quartz sand was somewhat pulverized. The quartz sand grains were smaller than AS O No. 40. and 43.1% of the total grains were larger than ASTM No. 80 The grain size of the quartz. Sent was smaller than runs 1 and 2. 57.7% of the quartz sand grains were larger than ASTM No. 8i The mixture could be granulated and shaped into pellets. The strength of the pellets was however A technical process is inadequate.

No. 7th J2..3 uarhcmal lime Mutate • 17.8 16.9] ■ 82.2 .. ".. Table V l "cil stone KcM ημιοΒο 1 5.3 16 Attempt 4 0 I hurry I "» 50.0 20th . i sodium 0 0 0 40 Quar / sand 0.4 (I. 0 60 _. j. 3.S 0.3 0.2 Grain sizes 80 0 8.6 2.4 1.0 ASlM 100 0 15.2 6.0 16.6 120 0 17.2 13.2 N to 120 0.4 54, n 10.4 i 6 to 20.9 Remarks 67.7 20 to 18.3 40 to 15.9 60 to 44.5 80 to KM) to until

Grain sizes
ASlM No.

80 to 100

100 to 120

to 120

... j nairium lime

(Juai'zsaiiu,

stone

0.5

8.9

90.5

Γ'-οΙ 13.2 Po 15.2 10.4 4.4 17.2 67.7 10.1 54.8 82.2

Medium
Grain size

Remarks

15th

20th

In Experiment 4, the quartz / sand was pulverized to a grain size smaller than ASTM No. 60 S:% of the total granules were larger than ASTM No. 80. The batch granulated better as the mixture of Versu.h 1 There were pellets echoing form.

Table Vl

Attempt 5

^ in sizes 1
\ STM No. I ^Quar

0
0
0
0
0.6

17.3
16.2
65.9

S to
6 to
until
until
until
SO to 100
to 120
until 20

16
20th
40
60
80

0.6

lime c.irbunat stone I c ' 1".., - Il 0 0 0 0.4 0.3 3.8 2.4 8.6 6.0 15.2 13.2 ! 7.2 10.4 54.8 67.7

("oil

ü.2 |

0.9-3.7

2.6

16.3] "\ 15.4 96.3 64.6

In experiment 6 the quartz sand was ground so strongly that that almost all of the grains were smaller than ASTM No. 100 and the proportion of grains with a Grain size smaller than ASTM No. 120 was larger than in Experiment 5. The mixture could be granulated excellently and the pellets obtained had a very smooth surface.

From the above experiments it can be seen that when using GlasrohstofT mixtures Granules or pellets with the special grain size can be produced by the method of the invention from which glass can be fused in a much shorter time than from the usual mixtures This can be seen from experiments 4, 5 and 6.

In a second series of experiments, mixtures of the same grain sizes as in experiment 4 were granulated and shaped into pellets. 200 g of the obtained pellets were heated and then dried for 2 hours by gradually heating to 500 ⁰ C in the electric furnace to the temperatures shown in Table VHL a certain time. The test conditions and the results are summarized in the table.

Table VIII

Melting temperature

1250

1300

1350

"1400

Melting time, minutes 35 45 25th X y X X y O X O O > " O O O O

O O O O

Remarks

In experiment 5 the quartz sand was placed on a kef * ' size smaller than ASTM No. 80. Just 3.7% of all grains were larger than ASTM No. 80. The device granulated excellently, the obtained pellets had a smooth surface and sufficient breaking strength.

Table VI
Trial 6

Grain sizes No. quartz ASTM 16 0 8 to 20th 0 16 to 40 0 20 to 60 0 40 to 80 0.1 60 to

sodium lime carbonate stone 0 0 0 0 0.4 0.3 3.8 2.4 8.6 6.0

Medium grain size

I% |

0
0
0.2 3.3

0.9

■> 1

55

60

e> 5 \ = Considerable amounts of remaining quartz sand,
y = Small amounts of remaining Quurzsand.
ο = no residue of quartz sand.

In these experiments there was faster melting and faster refining itself lower temperatures than usual with batches for grain sizes. He has also learned from the experiments give that the result of the granulation and deformation into pellets, especially through the grain size of the quartz sand in the Gemengi is predominantly present. It gets better «: Results from quartz sand with a smaller grain size obtained, but no significantly better results are obtained if the grain size is above one If a certain value is reduced even further look for the specified grain size for the quartz / sand

An important advantage of the method of the invention is then to see that it succeeds. Ctiasrohsuiife ir to be obtained in a form in which the formation before ¹ St- _U (- and the separation of the components is avoided, and which are easy to store and transport

309 638'37ό

leave. For the production of glass raw material mixtures in cookie form according to the method of the invention, Kaliiimc.ubon.il or dolomite can be used in place of Sodium carbonate and limestone can be used. Mixtures with customary additives can also be used be like borax. Phosphoric acid. Barium oxide and red lead

In Table IX, a glass raw material T genius is shown with a particularly preferred grain size distribution given for the method of the invention.

Table IX sodium ■ "" " Medium • 27 ν- Grain sizes carbonate lime Grain size ASTM No. Quar / sitnd | "· Ο) stone .. < ⁰ '°' ... η (%)
■ 0) 14.4 \ ₇ , 4. 20 0 0.1 ο 0 57.8 20 to 40 0 3.6 0 1.2 40 to 60 0.3 7.0 2.5 13.4 60 to 80 17.4 14.3 6, i 13.1 80 to 100 12.3 16.2 14.3 00 to 120 14.6 58.8 12.1 to 120 55.4 65.0

The glass raw materials were mixed with small amounts of coloring additives and other additives. After thorough dry mixing, the blend was in the presence of 12 to 20 percent by weight Granulated water. The resulting rounded pellets with a diameter of 4 to 20 mm were at An initial temperature of 110 to 130 ° C dried and then further heated to temperatures below 500 C.

As mentioned above, various reaction products are used when drying the pellets arise as a binder. Sodium silica is particularly beneficial in terms of the strength of the pellets important influence. It was previously believed that quartz and sodium hydroxide were at low levels Do not implement temperatures with one another, or only to an insignificant extent. When using powdery However, glass raw materials of the critical grain size described above take place when the pellets are dried Above 100 C formation of sodium silicate. The formation of sodium silicate increases with increasing temperature to. The drying time must be such that the pellets do not crack. in the otherwise the tendency to form dust also depends on the amount of sodium acid formed away. The smaller this amount, the greater the tendency to form dust. A typical composition for a glass raw material mixture which can be used in the method of the invention is in Table X given.

Table X Components

Quartz sand

Sodium.
Sodium hydroxide.

limestone

Glauber's salt

Parts

100
19th

8.5

2 ?

1.0

Components

Potassium dichromate

Cobalt oxide

carbon

Parts
0.0. '

0.005
0.0K

The invention is based on the drawings

ίο further explained.

Fig. 1 shows a flow diagram with the essentials Procedural stages;

F i g. 2 shows .schematically a device for Carrying out the method of the invention.

According to the flow diagram of FIG. 1, the ingredients listed in Table X are weighed out on automatic scales and mixed thoroughly with one another. The mixture is then comminuted in a hammer mill, mixed with 30 to 70% sodium hydroxide solution and granulated in a granulating device with the addition of water and shaped into pellets. The pellets come from the granulating device into a drum, in which they are brought to their desired size. From the drum, the pellets go into a dryer, in which they z. B. be dried at an initial temperature of 130 to 180 C. The pellets are then mixed with 40 parts of ground broken glass and placed in a tub. An excellent glass of blue color is obtained. The glass yield is; 50% more than when using a conventional p.:iver-shaped glass raw material mixture.

In Fig. 2, the method of the invention is Ni> ematic explained. Quartz sand. Sodium carbon. :: and Limestone, each to the desired grain size pulverized, are stored in bunkers 1. Sodium sulfate. Potassium dichromate. KobaltOAi! and Carbon in weighed amounts are thoroughly mixed together in a mixer; and kept in bunker 2.

As the process for the production of the Gla.sroh-.toff mixture is carried out in the form of biscuits in 24-hour operation, the glass raw materials are on automatic scales continuously weighed and

transported in the desired Mensienverhälinissen in the drum mixer 3, where they are thoroughly mixed with one another. The mixture then passes into the kneading unit 4. The knife, which is arranged in the form of a screw, contains. In this kneading unit, the mixture is moistened with 30 to 70% sodium hydroxide solution. The mass agglomerates and is dispersed and evenly distributed by means of the rotating knives of the kneading machine. Thereafter, the wet mass is fed into a "Granuliervorrichtung5. Preferably this Granuliervornchtung a disc granulator. Erfordcrlichenfallseine further quantity is fed to water in the Granuliervorvorrichtung. Volume taking into account dei added during the addition of sodium hydroxide solution Wasserte is the Wassergehalt'auf \ 2 to 20 weight parts per 100 parts by weight of solids. The pellets formed are kept in motion in the disk granulator, similar to dragees in a drainage pan. The granulator is equipped with guide rods, a floor scraper and a wall scraper with the help of which the mass is pelletized The preformed pellets come from the granulating device into a feeder

mel 6. in which they are deformed to the required size by rolling. From the drum 6 the pellets passed through a chute into the dryer 7. Her dryer 7 is an inclined roasting oven in which the hot I.lift is circulated. The temperature at the furnace inlet is kept at 110 to 130 ° C. This temperature is required to evaporate the water from the pellets. If the temperatures are initially higher, the pellets can crack as a result of thermal shock and thereby lose their breaking strength The maximum temperature in the roasting oven should not exceed ^{5 (KV 1 C.}

The dried pellets come from the roasting furnace onto the sieve 8. Pellets that are too large are produced by a Retained sieve with a mesh size of 15 mm and

arrive in a crusher 9, from which they are returned to the granulating device 5. Pellets less than about 4 mm in diameter are similarly screened out and also returned to the granulating device 5. Pellets with a diameter of 4 to 15 mm, possibly together with broken glass, fed into the permanent tub 10.

When using the pellets produced according to the invention as a charge for a permanent tub the amount of glass that can be processed per 24 hours from 130 tons to 170 tons, d. H. by about 30%. increase. In addition, the heating oil consumption could go from 210 to 230 1 to 170 to 1801 Ton of glass to be diminished.

1 sheet of drawings

Claims (6)

Patent claims: 1. A process for the production of glass raw material mixtures in cookie form by granulating the powdery glass raw materials in the presence of sodium hydroxide and water and heating the granules, characterized in that a homogeneous mixture of the powdery glass raw materials, of which m ^; nde>tens> o SO ⁰ O the grains have a grain size smaller than ASTM No. 80 (0.177 mm) and the grain size of the quartz sand is smaller than ASTM No. 60 (0.250 mm). where at least 80% of the quartz sand grains are smaller than ASTM No. 80, in the presence of sodium hydroxide with 12 to 20 parts of water per 100 parts of mixture granulated according to known methods and the resulting cookies initially at temperatures of 50 to 2nd C and finally at temperatures below -: o half MX) (- "dries. 2 ".erfahren according to claim 1, characterized in that one uses glass raw materials with a mutated grain size of less than aK ASTM No. w> (0.250 mini, of which mirdesiens ⁷ o'-',, the grains smaller than ASTM No. 100 ( 0.149 mm) and at least 70 " _{u of} the quartz sand grains smaller than ASTM # 100. 3. The method according to claim i or 2, characterized in that that for granulation 100 parts of the mixture are moistened with 15 parts of water and the obtained cookies first dry at 110 to INO C with 130 to 300 C hot gases. 4. Method n.ich one egg claims 1 to 3. characterized in that the sodium? s hydroxide is added to the powdery ^ glass raw materials in the form of a 30- to 70 ° oigen sodium hydroxide solution and the granulation at temperatures of at least 100 C. 5. The method according to claim 1 to 4, characterized in that the dried cookies sieves and the fraction with a diameter of 4 to 20 mm. especially 4 to 15 mm. wins. 6. The method according to claim 1, characterized by 4s indicates that the granulation is carried out in the presence of at least 20 percent by weight on the total mass. Sodium hydroxide. 5 ° The manufacture of the mixture of glass raw materials, d. H. of the "mixture" is one of the most important preparatory work Measures for melting. Most of the raw materials are sand. Soda, potash. Limestone. Dolomite. Mennege, saltpeter. Sulfate, etc. mixed together with so much moisture that something there is more water available than the soda needed for monohydrate formation. The water is almost generally introduced as sand moisture. Most t.o glass raw materials tend to generate dust. One lays therefore emphasis on the dust-tight construction of the individual components, especially the mixers and conveyor belts. Occasionally the mixture is moistened after mixing or also during mixing To avoid dust formation. In addition, moistened mixture should be easier to clean than dry, The briquetting of the weakly moistened batch batch to form shaped bodies of brick format has proven successful. From the German patent 4S4 594 it is known, the powdery mixture of Glass raw materials, if necessary after prior briquetting, initially one to bind the powder * sufficient heating with a temperature rise that is so slow and led to such an extent subject that which is below the formation temperature of the glass possible conversions occur evenly through the whole mass and any reaction gases formed escape almost completely. It is known from German Offenlegungsschrift 1,814,624. To granulate glass raw material batches and Z. B. to form granules, briquettes or egg briquettes by turning the powdery Glass raw materials granulated after the addition of water and alkali hydroxide and the granules formed in this way then subject to heating at a temperature and for a period of time sufficient to cause the reaction de. » \ lkali hydroxides with the carbonates present in the mixture are hot-filled. \\ irzug.iwei> c the granules are heated to a temperature between 100 and HOC The methods described above have one or more disadvantages. Either they are Process uneconomical, especially if that Mixture is subjected to pre-sintering or the shaped bodies produced during granulation are of greatly fluctuating size and unsatisfactory strength, and melting is still accompanied by excessive bloating and fluffiness. With the known glass raw material granulates there is a rapid reaction on the outside, but the cone formed by the insert remains inside however cold. The easily liquid compounds that form quickly flow out of the granulate mixture, separate this and make the subsequent homogenization of the melting glass more difficult. Because of Due to their high alkali content, they particularly eat up the port and tub walls. For the whole The process of transferring the granulate mixture into workable glass is still disproportionate great time required. As a result, the amount of glass that is out in a given time can be worked out in a given furnace, and thus the prime costs unnecessarily high due to excessive energy consumption, wear and tear on refractory material, etc. The object of the invention was to provide a process for the production of glass raw material mixtures in the form of cookies (Pellets), which are ideally suited as a feed for glass melting furnaces. This task is achieved by the invention. The invention thus relates to a process for the production of glass raw material mixtures in the form of cookies by granulating the powdered glass raw materials in the presence of sodium hydroxide and Water and heating of the granules, which is characterized by this. that you get a homogeneous mixture of powdered glass raw materials, of which at least 80% of the grains have a grain size smaller than ASTM No. 80 (0.177 mm) and the grain size en »Quartz sand is smaller than ASTM No. 60 (0.250 mm). where at least 80% of the quartz saudkömci " are less than ASTM # 80 in the presence of sodium hydroxide with 12 to 20 parts of water per HX) TeJIc mixture according to known