JPS61500490A - Methods useful for producing glass-forming mixtures and glass compositions having controlled molar ratios of major oxide components - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] with controlled molar ratios of glass-forming mixture and major oxide components METHODS USEFUL FOR PRODUCING GLASS COMPOSITIONS TECHNICAL FIELD The present invention relates to alkali-resistant glass. It is commonly associated with vitreous bodies. Both have a special relevance to glasses that can be made into fibers.

Background technology Natural mineral zeolites are monohydrated alkali metals and zeolites with an open three-dimensional crystal structure. (or) a group of alkaline earth metal aluminosilicates. Each of the many minerals Olites are known and have been described in the literature, with 11 types (11 ) minerals, i.e., analzite, rhyofluorite, clinotylozeolite, erionite, ferri Elite, diabolite, turbidite, mordenite, soda zeolite, volcanic zeolite and wyra Kaites constitute the major group of mineral zeolites. These major minerals Chemical and physical properties of olites and many minor mine zeolites ) pages 1235-1274; Widely described. These publications also explain the geological existence of the natural mineral zeolite. and natural mineral zeolites that have been proposed or are currently used on the market. Several industrial and agricultural applications are described.

Natural mineral zeolite is a “synthetic zeolite” widely described in many recent papers and clocks. It is important to recognize that it is a substance in a completely different class from "olite". . Because there is no generally accepted system for naming synthetic zeolite tones and Some synthetic materials suggest possible similarities in structure with natural mineral zeolites. Because it shows an X@ diffraction pattern, some reports in the literature and by We have described a type of synthetic zeolite consisting of the second version of the "synthesis" of Ito. For example, synthetic zeolites such as “synthetic analzeite” or “synthetic mordenite” It was described as. However, in the Breck reference cited above, As stated, this method is technically incorrect and in addition to Confusion between different materials, namely natural mineral zeolites and synthetic zeolites. I was just guiding. It is recognized that there are structural similarities between the two groups. However, natural mineral zeolites are similar in structure and properties to synthetic zeolites. They constitute a very different and different class of substances.

Glasses are mostly composed of silica. However, silica is very Since it is a difficult substance and can be melted at an appropriate temperature, it is possible to make a composition for glass forming. Substantial amounts of soda ash, lime or other fluxes are often added to the silica to make it Added. Finished glass to provide specific properties, such as color or chemical resistance. Small amounts of other substances, usually elemental substances or oxides, are commonly added to the glass melt in order to , added. To make what is described as a porous low temperature glass composition The kleinotylozite and glass mixture was heated to 800°C (much lower than the melting point of either). An experiment was reported on firing with Tamura's Japanese Tokukai-an 49-988. 17 (1974) mentioned above by Mumpton. See page 197.

Jill as in Pilkington's R Glasses In glass made by containing conia and (or notitania) Lucariness is given. These substances increase the alkali resistance of the glass body. However, these are refractory materials that increase the glue point of such glasses. Ma Ta.

Zirconia and titania are silica, soda, and calcia. ) and soda lime, which is a much more expensive material than the usual components of silica glass. , tends to add cost to the glass.

Although calcia tends to lower the overall melting point of the glass composition, it For using calcium oxide in amounts greater than fifteen percent (15%) There are six major caveats in glass technology.

It is an object of the present invention to produce an alkali-resistant glass that can be made into fibres.

Another object of the invention is to use readily available aluminum and alkali materials. Modification of silica sources, such as naturally occurring zeolite materials, using earth metal compounds and achieving an optimal ratio of certain components of the resulting glass composition.

Another object of the invention is to control the molar ratio of certain oxides within the glass composition. The aim is to optimize alkali resistance and GI fibrosis ability by

A key point of the present invention The present invention provides glass compositions that have remarkable force resistance in alkaline environments and, in particular, easily Includes glass compositions that are fiberizable.

More than 4? In particular, these glass compositions contain a silica source, e.g. a naturally occurring zeolite, at least one source of alumina, preferably a source of silica; an alumina source, and at least one alkaline earth ftbiride source, Directed by the Cal7a source, Silica Plus Alumina vs. Calcia Plasma The molar ratio of gnesia is about 1.4:1 to about 20:1 for one foot of calcia content. and for lower calcia content it falls within the range of about 1.6-2.3, mainly silica, alumina and alkaline earth oxides, especially calcia, glass compositions arise. Soda, potassia and dahlia (1) oria) and small amounts of zirconia and other glass-forming and glass-modifying components. It's okay. Further, the present invention also provides a glass body, especially a fiber, formed from the above-mentioned glass composition. is included within the scope of.

Brief description of the drawing Figure 1 shows silica plus alumina versus calcia for various glass compositions. Plus Alkali resistance and fiber forming ability with a curve drawn against the molar ratio of magnesia This is a graph of force.

DETAILED DESCRIPTION AND BEST MODE FOR CARRYING OUT THE INVENTION The present invention is a Excellent viscosity and particularly suitable for fiberization by drawing the glass through a Concerning the production of alkali-resistant glasses with opacifying properties. of such glass The production preferably involves glass containing a small proportion of soda and/or bottasia. However, for glass having a calcia of 24 or more, it is about L4:1 to about 2.0. :1, preferably about 1.5:1 to about 1.9:1 and especially tJl,6=1 to about 1.8:1 7 Lika glass alumina to calcia plus moles of magnesia silica source, especially sodium, potassium and/or aluminum The method includes combining the glass forming material 5 with a silicon material containing a silicone material containing a siliceous material. Contains. For glasses containing less than about 24% calcia, the molar ratio is generally from about 1.6 to about 23, preferably from about 1.8 to about 2.3 and especially from about zO to It is about 23.

The glasses of the present invention contain aluminum, calcium, sodium and potassium in various grades. production from a silica source with 1 or more other materials such as can be included.

In one particular embodiment, silica in the glass formed from the glass forming mixture The molar ratio of Ka plus alumina to calcia plus magnesia is about 1.4 to about 2 , preferably in the range of about 1.5 to about 1.9 and especially about 1.6 to about 1.8. in which the glass formed from the mixture contains about 45 wt.S. to about 60 wt.% silica. , about 2% by weight to about 2011% alumina, about 24% to about 301% by weight. Lucia and about 0 weight chill about 24 weight M magnesia and less than 3% by weight zirconia The glass-forming mixture comprises at least one 7-liquid source, often a silica source containing a small amount of alumina, for example less than about 50% alumina, at least It also includes one additional source of alumina and at least one source of calcia.

These molar ratios are determined by the addition of small amounts, for example up to 5 parts and 11 parts of soda and botanicals. particularly applicable to glasses containing A, more particularly in small amounts, for example about 5% by weight It can be applied to glasses containing up to 3i, 1J, and especially about Glass having a combined soda, bottasia and dahlia content of about 10 g Applicable to Furthermore, compared to the molar ratio, the OaO + MgO content is approximately 25 East Optimum properties such as fiberizing ability and alkali resistance It is most effective in providing jt. In most cases, magnetic The shea content should be less than about 10% by weight and especially less than about 5% by weight. preferable.

In another nine aspect, the seven liters in the glass formed from the glass forming mixture Plus alumina to calcia plus magnesia molar ratio of about 1.6 to about 23 , preferably in the range of about 1.8 to about 13 and especially about 20 to 23. The glass formed from the mixture contains about 45 to about 601 layers of silica, about 2 layers. About 20% by weight of alumina, about 18% to about 22% by weight of calcia, about 0 Contains about 30% by weight of magnesia and less zirconia than triple tS. uni, the glass-forming mixture comprises at least one silica source; at least one silica source; It includes an alumina source and at least one calcia source.

Boron and zirconium components may be added to the processing properties of batch materials or on finished glass articles. It is not present in naturally occurring mineral zeolites in amounts that have any effect. finishing The glass article has about 6 layers less B2O3 and about 3% less Zr by weight. Contains boron and zirconium components in glass batches in small quantities such as having 02 It is often desirable to Containing a boron compound in the glass batch of the present invention This tends to improve the fiberizing ability and reduce the melt solubility of the resulting glass. - In some cases, the presence of zirconia in the glass already has remarkable alkali resistance. The present invention tends to improve the alkali resistance of naturally occurring glasses. of particular relevance to glasses formed from zeolites and in particular It is particularly relevant to glasses in which the glass provided the primary glass formation.

Such glasses can be easily and The fact that it can be formed at no cost is important, as will be discussed later. Ru.

Many naturally occurring zeolite materials, especially those with high alumina content, are Under suitable conditions, it can be formed into glass, especially as fibers. Glass forming objects Zeolite as a quality has many advantages. Naturally occurring zeolite has already undergone a reaction and the various elements are intimately mixed with each other and react. It is. Zeolite materials are also special because they have very low sulfur content. It is useful for In particular, very useful glass bodies include varying amounts of alumina and Calcia or an alkali such as a combination of calcia and magnesia It is formed by combining earth metal components with zeolite in the following composition range: The percentage expressed as the percent double weight capable of producing silica - approx. 60Ll) to about 78 inches, Alumina - about 6% to about 30%, Fe203 - about 1 inch to about 3chi, calcia - about 0chi to about 15%, magnesia - about 1chi to about 3chi, botasia About 1 inch to about 5%, about 1 inch to about 5 inches.

A suitable source of alumina for inclusion in the glass forming mixture of the present invention is aluminum Seed crystals with high alumina content such as aluminum, kaolin, montmorillonite, etc. aluminum compounds such as aluminum chloride, aluminum sulfate etc. include.

Suitable silica sources include zeolite materials, alternative silica, and those with high silica content. A glass-forming composition containing various glass currents having the above-mentioned glass composition Calcia source, e.g. finely ground limestone, in proportions to obtain a silica source , for example finely ground zeolite materials of the above composition and finely ground It can be easily formed by mixing it with an alumina-forming substance.

Upon cooling, the glass material has a strength substantially equal to that of typical soda-lime silica glass. It exhibits good physical properties with good degree and other qualities. If the glass has the above composition parameters If you have a meter, it is approximately 10 to 2 times more expensive than typical Ngu lime silicate window glass. 0 times better resistance to alkaline solutions as well as improved fiberizing ability was achieved. It will be done.

In addition to improving the fiberization ability and durability of the glass in alkaline environments, increased alkali zeolites containing mina and high calcia and/or magnesia content t' type of glass has other advantages as well. Alumina-forming substances and calcium and (' or) addition of magnesium compounds to even out the diversity in the olide composition. There is a tendency to unify. Zeolites are naturally occurring substances and their composition Not homogeneous or uniform in composition. Naturally occurring zeolites contain varying amounts of alkali. Contains mina and calcia. Alumina content is highly dependent on mineral type It may change. A few mineral zeolites form glass that can be easily made into fibers. Contains alumina in an amount sufficient to achieve However, most zeolite materials contains lower amounts of alumina in different grades. Therefore to such zeolites The addition of alumina has good fiberizing ability and the addition of alkaline earth metal components Addition of a substantially uniform composition from notch to patch with good alkali resistance A glass-forming composition comprising:

Although small amounts or polyelectrolytic zeolite materials can be used, good The result is a glass containing approximately 35% or more of naturally occurring zeolite. Achieved from a forming composition. Improved fiberization ability is present in zeolites. If no additional silica, alumina, etc. are included in the bunch in the same ratio as present, Achieved from glass forming compositions having about 40% or more zeolite Ru. Excellent results are achieved with zeolite compositions of about 50% or more.

Such naturally occurring zeolites may contain a large amount of alumina, but However, it typically contains up to about 10% by weight. Therefore, improved fiberization In order to obtain a glass with the ability, about 0.1 weight [%~ Alumina formation at about 20% by weight, and preferably from about 2% to about 15% by weight. zeolite material is added to the zeolite material.

The alkaline earth metal component is added to the alumina modified gel as described elsewhere in this specification. It is also preferred that it be added to the olite glass forming composition. Uniform patch composition before to achieve one or to achieve a special silica-to-alumina ratio. It is, of course, within the scope of the present invention to add silica. Usually such a series Mosquito stocking is not necessary, but may be done if desired. soda, bottasia etc. Additions may also be made, but low soda and bottasia content is preferred. So, such a sword 0 will not be added.

Zeolites contain relatively substantial water, ie, are hydrated materials. water Summed crystalline materials generally tend to melt at lower temperatures. Therefore, Rather than starting the lath-forming operation with silica, it There are even more advantages to starting with it.

The melting temperature of the glass of the present invention is such that the glass fibers are drawn by passing through a platinum die. δ, preferably within the range of about 300°C to about 1500°C. . Glass fibers can also be formed by spinning or other techniques. death However, the formation of continuous strands occurs in platinum or platinum-rhodium orifices. This is best achieved by stretching the film through a

The fibers of the glass compositions of the present invention are made of highly alkaline and smoky substances such as cement. It is particularly useful as it can be used to strengthen cement and plaster. Such fiber Fibers can also be used to strengthen various types of organic matrices. Ru. However, reinforcing cement with such fibers is difficult because asbestos is Since it has been frequently used for this purpose, it provides an extremely advantageous use. Tow The use of asbestos is declining due to various health and/or environmental concerns.

Continuous strands of glass fibers having the glass compositions described herein or The mat effectively strengthens the concrete body.

Example 1 Naturally occurring zeolite is ground into granular alumina, as shown Mixed and dissolved with calcium carbonate, magnesium carbonate, limestone or dolomite It was melted to form a glass body and fibers. Zeolite composition and added aluminum temperature of about 350°C to about 1500°C, depending on the amount of alkaline earth metals and alkaline earth metals. Molten St was carried out batchwise in a large crucible.

Table n Composition and properties of zeolite glass Glass mni glass ll1b glass 1Ilc55 zeolite 55 ze Olite 55 Zeolite (weight%) 2.5 Alumina 5 Alumina 5i02 51.5 50.7 50.0At2o, 8.9 12.0 15.0Fe 203 0.6 0.6 0.5 0aO30,628,326,l MgO3,13,13,0 K20 2.9 2.8 2.8 Na20 2.6 2.6 2.5 Fiberization ability Poor Weak Good Very good Processing range 10 50 100 (℃) molar ratio ShiPt Tayu et al. 1.51 1.64 1.78Cmσ0Mgσ In Table 1, glasses Ia and Ia show good resistance to alkaline corrosion. However, it exhibits poor fiberizing ability and has a limited processing temperature range. Contrast glass! b and llc have compositions within the scope of the present invention and are resistant to alkali corrosion. 10,000 to maintain good resistance and have improved fiberizing ability and processing range .

The glasses mb and mcd in Table 1 have a composition within the scope of the present invention and have a fiberizing property and This shows that the processability is progressively improved.

A slight decrease in alkali resistance was experienced using glasses I[lb and l[lct]. However, the alkali resistance is still very good.

Example■ The glass-forming material was finely ground and given the following table (expressed in percent by weight): The whole glass body and fibers are mixed and melted with specific additives as identified in the accomplished. From about 250°C to about 150°C depending on the batch composition of additives and the amount of additives. Melting was carried out in a patch mode in a small crucible at a temperature of 0°C.

Table ■ Composition and properties of alkali-resistant glass Heavy! Chi Glass Wa Glass IVb Glass IVc Silica 50.0 47.5 47.5 Alumina 10. O] 0. O15.0 Dahlia 0.0 2.5 2.5 Calcia 35.0 35.0 30.0 Magnesia 5.0 5.0 5.0 Melting temperature ℃ 1450 1400 1400 #R Fibration ability Poor Good Good Processing range ℃10 30 80 The glasses listed in Table 1I1 can be used for silica, aluminum 6, calcium carbonate, Iria and magnesium carbonate. Zeolite substances are not present in the It was. To determine the fiber-forming properties, alkali resistance and other properties of the resulting glass These glasses were made from traditional glass-forming materials.

Glass IVc has a composition within the scope of the invention and exhibits very good properties. the The melting point was suitably low, and the alkali resistance was very good at -10,000. fiber is in trouble It was formed without difficulty.

Table N Zeolite 50.0 55.0 60-0 people + 2032.5 2.5 2. 5 B20! , 2.5 2.5 2.5 0aC0340,037,532,5 MgC0,5,02,52,5 8i02 46.6 49.9 53.2 people t2o3 11.3 11.8 1 2.3B2033.3 3゜23.1 Fe203 o, s O,50,6 0aO30,027,523,4 Mg0 3.4 1.8 1.8 20 2.6 2.8 2.9 Na20 2.4 2-5 2.7 Melting temperature °C] 350 1400 1400 (5% NaOH 1 Judochi) 1°51°43°9 Fiberization strength Good Good Good good Processing range (C) 30 50 70 Glasses Va and Vb showed poor alkali resistance; however, the 9-fibrilization ability was They were rated as fair and good, respectively. Glass Vc has better alkali resistance Although lower, it showed an improved processing range than glasses Va and Vb.

Glasses #3 to #d exhibited excellent alkali resistance and melting temperature. glass ■d and ■e has lower but substantial alkali resistance than glass ■1~Vic. The fiberization ability and processing temperature range are shown. Glass ■a has decreased to an unacceptable level. The machining range is shown below.

The glasses identified in Tables 1, Made from olite: 8102 82-8 weight percent Al2O38.4 weight percent Fe2O30-3 weight nose cent CaOO-9 weight percent MgO0,6 weight nose cent to 20 2.9 weight percent Na2O4, 1% by weight Small changes in composition may occur from patch to patch of zeolite.

In combined form, very small amounts of other elements, such as boron, manganese, zirconium , titanium, panadicum, antimony, barium are such naturally occurring zeolites. It may be present in the light. The weight of such substances is generally about 0.01 each less than 0.0% by weight, usually as low as 0.01% by weight, and can often be be.

In forming the alkali-resistant glass of the present invention, if one does not start with a zeolite material, such material is present in at least about 35% by weight of the glass patch mixture. It is preferable to have.

If the zeolite provides virtually all the silica content for the resulting glass If so, in that case, about 40 weights to 1 to about 50 weights or more of the Olites may be used in the glass patch mixture.

Glass patch mixtures are made of materials such as borax, colemanite, borate, ulexite etc. It may also contain a small amount of a component for forming I+J.

Various naturally occurring detrital silicate substances or borosilicates, or boroaluminosilicates Glass cullet is, of course, used to provide the boron component in the glass no match. may be used. Boron-containing components are typically present in glass patches in amounts up to about 6% by weight. and in the resulting glass typically about 0.1% to about 6% by weight, preferably or about 1% to about 5% by weight, and particularly preferably about 1% to about 4% by weight. is present in an amount sufficient to provide an N IJA content of .

Various glass compositions containing calcium oxide from about 24 fk to about 38 fk Figure 1 shows the fiber-forming ability and alkalization ability curves for . Silica Plus The glass composition identified by the molar ratio of alumina to calcia plus magnesia Plot on the abscissa. Values of the above molar ratios below about 1.4:1 are 9 fibrosis ability limit, that is, the value of 4 on the fibrosis ability scale. considered for clear purposes. a fibrotic potential of at least about 7 in a molar ratio of about 1-5 Preferably, the power value is present in the alkali-resistant glass, while about 1.6 molar An adhesion/separation capacity of about 9 in terms of ratio is particularly desirable.

Alkali resistance appears to decrease substantially proportionally as the molar ratio increases. However, fibrosis potential does not seem to have a linear relationship to molar ratio. Approximately 1 in contact and separation ability ．． It increases greatly at molar ratio values of 4 and above. Optimal alkali resistance is at a molar ratio of 18 or less Achieved by value.

Crystallization of various undesirable crystals during fiberization of glass due to the presence of soda and bottasia Therefore, it is important to fully control the molar ratio within the above range. This is particularly important in light. However, one of the at least Also discussed herein is the presence of sodium and potassium adducts in some patch materials. Listed n7 (silica plus alumina vs. calcia plus magnesi) Requires optimization of the batch materials to provide a glass composition with a molar ratio of do.

Applicability of Koto These glasses have a remarkable resistance to alkaline environments, especially in the transverse cord shape. Reinforcement material for concrete, plaster and other inorganic matrices Role as a fee? Let them act out.

This includes standard thickeners as reinforcing materials in cement and concrete bodies. Asbestos was undesirable due to the possible presence of seven nic health hazards. Because I don't think there is.

This is especially important.

The rLπ glass fibers formed from the glasses of the present invention can be used for example in cement and concrete. It has particular utility as a reinforcing material for cementitious bodies. kamen) A small amount of G2 in the Fm body. fibers, preferably glass fibers of the type described herein. from about 1% to about 10% by weight, and more preferably from about 1.5% to about 7.5% by weight, exhibiting increased strength when such objects are reinforced . Fibers are contained in cement (cement) in sufficient quantities to increase the strength of such objects. It will be done.

The glasses of the invention have excellent resistance to moisture degradation and Does not deteriorate or degrade during extended storage periods.

Although embodiments of the invention have been described as having a significant content of calcia, , substituting at least a small amount of other alkaline earth metal oxides for calcia. You can. For example, in the production of patches for melting into alkali-resistant glass. Magnesium compounds, especially carbonate, can replace at least some of the calcium carbonate. Magnesium may be substituted. Similarly, barium and strontium compounds and beryllium compounds, many of which are found in the same geographical regions as zeolites. It is a naturally occurring substance found in certain areas.

Oxides of alkaline earth metal elements include elements with a valence greater than three, such as silicon. , boron, and phosphorus (these include their oxides, i.e., silica, oxides of boron, and oxides of phosphorus) Glass-forming agent is a term applied to materials that can form a three-dimensional structure with objects. I can't get it. Divalent alkaline earth metal elements are alkali metals in glass. It is more tightly bound than the elements.

The sources of alkaline earth metals forming oxidized metals in the glass of the present invention are as follows: is: Alkaline earth metal compound source Calcium carbonate limestone Magnesium carbonate dolomite Magnesium silicate serpentine Barium carbonate electrotype stone Strontium carbonate Strontianite Aluminum silicate Beryllium Beryl Sources of calcium and magnesium carbonates are generally barium, strontium It is also much more abundant and valuable than the source of beryllium compounds. Also, Gala Although beryllium oxide combined in the body is not harmful, beryllium metal is toxic. It is thought that it is a sex.

The glasses of the present invention preferably have less than about 24 tS (Oa f) with excellent fiberization. Although it has the ability to contain a lot of calcia, it can also be used as a fiberglass material. It is particularly useful in alkaline environments. Also on such fiber glass A certain sizing and coating of further increases the alkali resistance of the glasses of the present invention. .

In addition to outstanding alkali resistance, the zeolite-derived glass of the present invention has good processability and and strength. These glasses can be in any shape, such as containers, sheets, fibers, etc. and especially used for any application that does not require transparency and colorlessness I can do it. Glass can be organic or inorganic! Trix, especially cement, plaster To be used as 7 lakes, foams (microspheres), fibers, etc. to strengthen etc. I can do it.

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Claims (1)

[Claims] 1. Silica plus alumina vs Cal in glass formed from glass forming mixture The above mixing under conditions where the molar ratio of shea plus magnesia is in the range of about 1.4 to about 2. Glass formed from about 45% to about 60% silica, about 2% to 60% by weight silica About 20% alumina, about 24% to about 30% calcia, about 0% by weight ~24% by weight magnesia and less than 3% by weight zirconia at least one silica source, at least one alumina source and at least one A glass-forming mixture containing a seed calcia source. 2. The glass form of claim 1, wherein said molar ratio is in the range of about 1.5 to about 1.9. Mixture for composition. 3. forming a glass comprising melting the glass-forming mixture of claim 1; How to do it. 4. forming a glass comprising melting the glass forming mixture of claim 2; How to do it. 5. Silica plus alumina vs Cal in glass formed from glass forming mixture The above conditions in which the molar ratio of shea plus magnesia is in the range of about 1.6 to about 2.3. The glass formed from the mixture contains about 45% to about 60% silica, about 2% by weight silica. % to about 20% alumina, about 18% to about 22% calcia, about 0% by weight % to about 30% by weight of magnesia and less than 3% by weight of zirconia. at least one silica source, at least one alumina source and at least one A glass-forming mixture containing a seed calcia source. 6. 6. The glass formation of claim 5, wherein said molar ratio is in the range of about 1.8 to about 23. mixture for. 7. forming a glass comprising melting the glass-forming mixture of claim 5; How to do it. 8. forming a glass comprising melting the glass-forming mixture of claim 6; How to do it. 9. The molar ratio of silica plus alumina to calcia plus magnesia in the glass is approximately from about 45% to about 60% by weight silica, with conditions ranging from 1.6 to about 2.3; About 2% to about 20% alumina, about 18% to about 22% calcia, by weight , from about 0% to about 30% by weight magnesia and less than 3% by weight zirconia. A glass composition containing. 10. 10. The glass set of claim 9, wherein said molar ratio is in the range of about 1.8 to about 23. A product. 11. The glass of claim 1, wherein said molar ratio is in the range of about 1.6 to about 1.8. Forming mixture. 12. A glass comprising melting the glass-forming mixture of claim 11. How to form. 13. 6. The glass form of claim 5, wherein said molar ratio is in the range of about 20 to about 2.3. Mixture for composition. 14. A glass comprising melting the glass-forming mixture of claim 13. How to form. 15. 10. The glass of claim 9, wherein said molar ratio is in the range of about 2.0 to about 2.3. Composition. 16. The mixture of claim 1, wherein said silica source comprises a naturally occurring zeolite. thing. 17. The mixture of claim 2, wherein said silica source comprises a naturally occurring zeolite. thing. 18. 6. The mixture of claim 5, wherein said silica source comprises a naturally occurring zeolite. thing. 19. 7. The mixture of claim 6, wherein said silica source comprises a naturally occurring zeolite. thing. 20. A small amount of glass fibers having a glass composition according to claim 9 A cementitious body containing. 21. A small amount of glass fibers having the glass composition according to claim 20 A cementitious body containing fibers. 22. A small amount of glass fibers having the composition of the glass as outlined in claim 5. A cementitious body containing. 23. A small amount of glass fibers having the composition of the glass as outlined in claim 6. A cementitious body containing. 24. The molar ratio of silica plus alumina to calcia plus magnesia in the glass is from about 45% to about 60% by weight silica, with conditions ranging from about 1.4 to about 2; 2% to about 20% by weight alumina, about 24% to about 30% by weight calcia, Contains from about 0% to about 24% by weight magnesia and less than 3% by weight zirconia. glass composition. 25. 25. The glass composition of claim 24, wherein the molar ratio is from about 1.5 to about 1.9. 26. 25. The glass composition of claim 24, wherein the molar ratio is from about 1.6 to about 1.8.