US2805145A - Exothermic metallurgical composition and method of introducing same into ferrous alloy - Google Patents

Description

United States Patent EXOTHERMIC METALLURGICAL COMPOSIIIUN AND METHOD OF INTRODUCING SAME INTO FERROUS ALLOY Courtland M. Henderson, Ferguson, George Lloyd Martin, Webster Groves, and Allan D. Gott, St. Louis County, Mo., assignors to Mallinckrodt Chemical Works, St. Louis, Mo., a corporation of Missouri No Drawing. Application March 25, 1954, Serial No. 418,758

Claims. (Cl. 7527) This invention relates to metallurgical compositions and processes, and more particularly to exothermic compositions useful in metallurgy.

Briefly, the invention is directed to an exothermic metallurgical composition which comprises a metallic oxide, a reducing agent for said'oxide and a source of basic oxide, said composition forming upon ignition a product containing at least one acidic oxide, said product remaining fluid at a temperature of approximately 2600 F. after absorbing at least approximately of its weight of titanium dioxide. The invention also includes the method of casting a molten metal which comprises placing pellets of the aforesaid exothermic composition on the bottom of a mold and then teeming so that said molten metal falls onto and ignites the pellets.

Among the several objects of this invention may be noted the provision of exothermic metallurgical compositions, which upon ignition'form products that resist the viscosity-increasing effect of refractory substances which may be absorbed from molten metal; the provision of exothermic metallurgical compositions which are useful to reduce the viscosity of the slag normally associated with molten metal; the provision of exothermic metallurgical compositions which when added to molten metal produce a fluid slag that is useful in absorbing or changing the physical nature of the nonmetallic inclusions in steel, other ferrous alloys, and certain nonferrous alloys, in rolled, forged and cast form; the provision of exothermic compositions which are useful to improve the hot-workability of ferrous alloys; and the provision of methods for improving the surface of metals cast in metal molds. Other objects and features will be in part apparent and in part pointed out hereinafter.

The invention accordingly comprises the products and methods hereinafter described, the scope of the invention being indicated in the following claims.

Heretofore, various alloying agents have been added to metals, such as steel, by forming the alloying element in the melt by reacting an oxide of the alloying element with a reducing agent in the molten metal. For example, small amounts of titanium and rare earth metals have been added to steel in this manner. However, the considerable quantities of oxides produced as by-products of the reduction are generally high melting, refractory substances which greatly increase the viscosity of the slag normally associated with the molten metal. Such viscous sla gs are recognized as undesirable in metallurgy because of the difficulty in separating them from the molten metal. Moreover, these viscous slags also interfere with the introduction of the alloying element into the molten metal, probably because the alloying element becomes entrapped in the slag. Addition of the usual fluxing agents, such as lime or calcium fluoride, is only partially successful in overcoming these difliculties. Lime, for example, has a limited fluxing capacity and if an excess is present, it may actually have the effect of increasing rather than decreasing the viscosity of the slag. When these fluxing agents are used in conjunction with known exothermic ice compositions for introducing alloying elements, the resulting slags are either viscous or become viscous because of the refractory oxides normally present in molten metals.

In accordance with the present invention, it has been found that these difficulties can be substantialy overcome through the use of a novel exothermic composition comprising a metallic oxide, a reducing agent for said oxide and a source of basic oxide. Preferably the source of basic oxide is present in an amount equivalent to not less than approximately 9% by weight of a basic oxide in the composition. The novel exothermic composition of this invention has an ignition temperature substantially above normal room temperatures and not greater than approximately 1300" F. and forms upon ignition a product containing at least one acidic oxide and preferably also at least one basic oxide. This oxidic product, i. e., the combination of oxides formed upon ignition of the exothermic composition, preferably has a softening point between approximately 1500 F. and approximately 2100 F., and it remains fluid at a temperature of approximately 2600 F. after absorbing at least approxi mately 15% of its weight of titanium dioxide. The exothermic compositions of the invention, when added to molten metals, produce a fluid slag which in addition protects the alloying element being introduced from oxidation and entrapment.

We have found that there is a correlation between the potential of any given metallic oxide to act as an'acidic oxide or a basic oxide in the product obtained upon igni tion of our exothermic composition and the ratio of the valence of the metallic element in the oxide to its covalent radius, a value which we designate as the p. s. i. value. For example, in the acidic oxide, titanium dioxide, titanium, the metallic element, has a valence of 4 and a covalent radius of 1.324 A., and the p. s. i. value is therefore 3.02. Similarly, in the acidic oxide, iron oxide, iron has a valence of 3 and a colvalent radius of 1.165 A., and the p. s. i. value is therefore 2.57. The acidic oxides as required by this invention are metallic oxides having p. s. i. values not less than 2.3 and not greater than 5.2, and the basic oxides as required herein are metallic oxides having p. s. i. values not greater than 0.9. For example in the basic oxide, sodium oxide, sodium has a valence of 1 and a covalent radius of 1.572 A., and the p. s. i. value is therefore 0.64. Oxides having p. s. i. values between 0.9 and 2.3 are not essential in the product obtained upon ignition of the exothermic composition, but they may be present.

In the practice of the present invention, the required acidic oxide and basic oxide can be provided in various ways. For example, if the reducing agent is silicon or a silicon alloy, the oxidic product obtained upon ignition of the exothermic composition will contain silicon dioxide, an acidic oxide having a p. s. i. value of 3.37. The acidic oxide may also be provided by including in the exothermic composition a substance such as sodium meta-silicate which does not take part in the exothermic reaction but furnishes both an acidic oxide, silicon dioxide, and a basic oxide, sodium oxide. The acidic oxide may also be provided by including in the exothermic composition an excess of a suitable metallic oxide such as titanium dioxide. The basic oxide may be most conveniently supplied by the selection of materials such as sodium or potassium nitrate, which are readily reduced to give sodium or potassium oxide, or, as pointed out above, by including in the exothermic composition any other suitable source of basic oxide such as sodium meta-silicate. The proportions of acidic oxide and basic oxide in the product obtained upon ignition of the exothermic composition may be varied over Wide limits depending upon the kinds and proportions of other oxides which are present in the product.

Apparently the acidic oxide and the basic oxide are able to combine over a wide range of proportions to give a fluid product which acts as a fiuxing agent for refractory substances. 7

' While, as pointed out previously, oxides having p. s. i. values between 0.9 and 2.3 are not essential inthe oxidic product obtained upon ignition of the exothermic composition, they may be present in certain instances. For example, the inclusion of rare earth oxides as part of the metallic oxide in the 'unreacted exothermic composition is frequently desirable since the rare earth elements improve the hot-workability of stainless steels. Even though 7 that the reaction may proceed incompletely or not at all.

the primary purpose of including the rare earthoxides in the exothermic composition is to furnish rare earth metal upon ignition of the exothermic composition, some rare earth oxide may be present in the product obtained upon ignition of the exothermiccomposition, either because of incomplete reduction of the rare earth oxides or as a result of reoxidation of' the reduced rare earth metal.

'Similarly, it is often desirable to employ as a reducing agent an alloy of silicon and a highly reactive metal'such as calcium. In that case calcium oxide, having a p. s. i. value of 1.15, is present in the product obtained upon ignition of the exothermic composition.

It will be seen that the product obtained upon ignition of the exothermic composition as required by the present invention can be provided by many combinations of metallic oxides, reducing agents, and sources of a basic oxide. Having selected. either the metallic oxide or the reducing agent which is most desirable for any particular exothermic composition, it will be seen that the choice of the other components of the exothermic composition will be limited and tea certain extent determined. For example, if, in order to minimize the amount of oxides having a pLs. i. value between 0.9 and 2.3 present in the oxidic product obtained upon ignition of the exothermic composition, silicon metal is selected as the reducing agent, itwill be apparent that the metallic oxide must be selected from among those which are reducible by silicon metal at the temperature of the molten metal being treated. Likewise, if it is desired that titanium dioxide should be part or all of the metallic oxide component of I the exothermic composition, the reducing agent mustbe selected from among those which are capable of reducing titanium'dioxide at the temperature of the moltenmetal being treated. Suitable metallic oxides for use in the exothermic compositions of the present invention may be selected from the oxides of useful metals such as iron, titanium, the rare earth metals, ziriconium, vanadium, niobium, tantalum and hafnium. Alkali metal nitrates or othermaterials which will provide a basic oxide, such as sodium metasilicate, are suitable sources of basic oxide. Examples of reducing agents which may be employed in the exothermiccompositions of this invention are silicon metal, silicon-zirconium, calcium-silicon, magnesium-aluminum, calcium boride, ferrosilicon,'mangesium metal, magnesium-containing alloys, aluminum metal,'and mixtures thereof.

When relatively less active reducing agents such as silicon, calcium-silicon, and calciumv boride are used, it

is advantageous forthe exothermic composition to include a'primer, i. e., ja substance which lowers the ignition temperature of the exothermic composition by providing a large'amount of additional heatwhich raises the temperature of the exothermic composition quickly to its normal reaction temperature. The'primer may be a substance which, for example,'decomposes at a temperature substantially below that of the molten metal, or. it may be one 'whichis reduced by the reducing agent, or it may be one which is oxidized by the metallic oxide, or it may undergo a combination of these reactions; 'Where less active reducing agents are used L and a primer is not used, then by the time the-exothermic composition reaches its normal reaction'temperature after being added to the molten'metal, the reactants may be so widely dispersed It has been found that alkali metal nitrates are particularly useful as primers in the compositions of this invention since they are also a source of basic oxide. The alkali metal nitrates readily react with reducing agents, such as silicon metal, with the liberation of large amounts of heat. However, his not necessary for the primer to be a source of basic oxide and'other primers may be used in the exothermic compositions of this invention. Examples of other substances which may be employed as primers are aluminum metal, magnesium metal and barium peroxide. If these latter substances are used as primers, however, the source of basic oxide must be provided in other ways.

In the manufacture of these compositions an intimate mixture of the components is necessary for maximum efliciency of the reaction. Therefore, the use of finely ground materials isusually preferred.

The exothermic metallurgical compositions of this invention are useful for, introducing various alloying elements into steel and other metals and they are particularly advantageous compared to the compositions prethis invention may provide allof an alloying element referrous .alloys, other than by the addition of alloying elements. In general the effect of these compositions is to improvehot-workability, that is, to reduce the cracking or, tearing frequently encountered when metal ingots are hot-rolled or forged, thus increasing the yield of saleable metal from the ingot. The compositions of this invention are also useful in beneficially affecting the nature of theusual nonmetallic inclusions in steel, other ferrous alloys, and certain nonferrous alloys, in rolled, forged and cast form. 'The most obvious benefit may againbe an improvement inhot-workability in the case of forged metals, but it also is of advantage in some cases merely to change the physical nature of the nonmetallic inclusions. In the case of cast metals, impact strength andporosity-of the cast metal, and the fluidity of the molten slag may be improved. By some mechanism which is notfully understood, the products obtained upon ignition of the exothermic compositions of the present invention'appear to absorb or modify the amount and distribution of the nonmetallic inclusions. In some cases they appear to modify favorably the grain size and structure of the metal. The compositions may be used in conjunction with other'steel additives, such as deoxidizers.

While the exothermic metallurgical compositions of the present invention may be used in various forms such as,

V for example, powders, they are particularly useful and convenient when used in the physical form of pellets, preferably compressed pellets. A suitable size for these pellets is adiameter of about /2 inch, but they may be either larger or smaller. ,We have found that excellent pellets can be prepared using sodium silicate as a binder ciently strong and hard to withstand normal handling without breaking or disintegrating and at the same time they are readily ignited when added to molten metal. In some cases it is more convenient to partially dry the granulation before pelleting it and then remove the remaining moisture from the finished pellets. However, this is not necessary, and satisfactory pellets can be prepared from the fully dried granulated compositions. The use of the exothermic compositions of this invention in the form of pellets improves control and reproducibility of the exothermic reaction and increases the reduction of metallic oxide to alloying element.

We have further found that, when pellets of the novel exothermic metallurgical compositions of this invention are placed in the bottom of a metal mold, preferably in an amount which will cover a substantial portion of the bottom, and molten metal is teemed onto the pellets, the incidence of surface imperfections, caused by splashing of the metal in the mold, is markedly reduced. The improvement is greater than can be accounted for by the mechanical effect of pellets as such, and it appears that the exothermic reaction occurring upon ignition of the exothermic composition and the product thereof also contribute to the reduction of splashing and concomitant improvement in the quality of the molten metal. Moreover, the oxidic product obtained upon ignition of the exothermic composition, by forming a fluid slag which coats the sides of the mold, prevents the ingot from becoming welded to the mold and substantially reduces the inclusion of refractory foreign materials in the surface of the ingot. Excess slag, being fluid and less dense than the molten metal, readily rises to the top of the metal and protects it against oxidation as it rises in the mold. The coating of slag which surrounds the metal ingot or casting is readily removed, leaving a metal surface which has substantially fewer imperfections than castings made without the addition of the compositions of the present invention. Here again the most noticeable benefit is often an improvement in hot-workability which appears to be due in part to the improvement in the surface of the ingot resulting from the use of these exothermic compositions.

When an alloying element is to be added to a metal such as steel, it is particularly useful to add an exothermic composition to the molten metal in the furnace or in the ladle at the time of or just prior to tapping. When the primary purpose in employing an exothermic composition is to improve the ingot surface, a composition of the present invention is preferably added to the mold at the time of or prior to teeming. In some instances, additions of these exothermic compositions to the furnace, ladle and mold may all be desirable.

The amount of these exothermic compositions which is added to the molten metal is governed by the purpose for which they are to be used. It may, for example, vary from as little as one or two pounds per ton of molten metal to more than fifteen pounds per ton of molten metal.

The following examples illustrate the present invention:

Example 1 An exothermic metallurgical composition was prepared by directly mixing 43 parts by weight of rutile, 27 parts by weight of sodium nitrate and 30 parts by weight of milled calcium-silicon (Cassia). Since titanium tends to alloy with silicon, an excess of the latter over that required for reduction of the titanium dioxide is provided in the above formulation. The ignition temperature of thismix- I of the metallic reaction product were separated and re" moved. The remainder of the reaction product, which was composed substantially of acidic and basic oxides but which probably also contained finely dispersed metal, was ground. Removal of the metallic component of the reaction product facilitates grinding but is not essential since the presence of metal does not significantly affect the temperature at which the oxidic product melts. A portion of the ground mixture was then heated in a furnace provided with a calibrated thermocouple and the temperature was gradually raised until the mixture softened, as determined by touching the mixture with a steel rod. It was found that this mixture began to soften at approximately 2000 F.

To determine the absorption capacity of the mixture, further portions were directly mixed with weighed amounts of titanium dioxide. These mixtures were then heated in the furnace to 2600 F. and the mixture was tested by thrusting a steel rod into the melt and then withdrawing it. A mixture was considered to be fluid if it was nearly water-like and pourable in consistency and did not form threads when the steel rod was withdrawn. By determining this temperature for a series of samples containing increasing amounts of titanium dioxide it was found that the oxidic product obtained upon ignition of the above exothermic composition absorbed 25-35% of its weight of titanium dioxide and still remained fluid at a temperature of 2600 F.

Example 2 An exothermic metallurgical composition similar to that described in Example 1 was prepared in pellet form by thoroughly mixing milled rutile (4.26 lbs., 42.6%), milled calcium-silicon (2.98 lbs., 29.8%) and sodium nitrate 60 mesh and finer (2.76 lbs., 27.6%). The dry mixture was sprayed with a 50% solution of sodium silicate (0.68 lb.) and water (0.65 lb.) and again thoroughly mixed. This wet material was forced through a 12-mesh screen and dried until 0.33 lb. of water was lost from a weighed mass of 10 lbs. The partially dried but still moist mass was then sifted through a 1'2-mesh screen to form granules. The granules were compressed into tablets of approximately inch in diameter using a conventional tableting press. The tablets were then dried until 0.47 lb. of water had been lost per each 10 lbs. 0 tablets.

Example 3 An exothermic metallurgical composition containing rare earth oxides in addition to titanium dioxide was prepared by thoroughly mixing 35.4 parts by weight of rutile, 9.1 parts by weight of rare earth oxides (approximately 50% cerium oxide, the remainder being oxides of lanthanum, praseodymium, neodymium, samarium, gadolinium, terbium, ytterbium, dysprosium, europi-um, yttrium, lutecium, holmium, erbium), 29.2 parts by weight calcium-silicon (Cassia), and 26.3 parts by weight of sodium nitrate. The ignition temperature of this composition was approximately 1090 F. The softening point of the oxidic product obtained upon ignition of the composition was substantially below 2100 F. The oxidic product absorbed 25-30% of its weight of titanium dioxide as determined by the method described in Example 1, and still remained fluid at a temperature of 2600 F.

Compressed pellets of this composition, approximately inch in diameter, were prepared by the method described in Example 2.

Example 4 Another exothermic metallurgical composition containing rare earths and titanium dioxide was prepared by thoroughly mixing 37.9 parts by weight of rutile, 3.8 parts by weight of rare earth oxides, 30.2 parts by weight of calcium-silicon and 2 8.1 parts by weight of sodium nitrate. The ignition temperature, softening point and absorption capacity were substantially the same as for V mained fluid at 2600 F;

An exothermic metallurgical composition similar to that described in Example 1 but containing the mineral ilmenite (FeO.TiO2) in place of rutilewas prepared by mixing 43 parts by weight of finely ground ilmenite with 30 parts by weight ofcalcium-silicon and 27 parts by weight of sodium nitrate. Thiscomposition had an ignition temperature of approximately 1090 The softening pointof the oxidic product obtained upon ignition of the composition wasapproximately 2100 F. The oxidic product absorbed more than of its weight ofititani-um dioxide asdetermined by the method described in Example 1', and still remained fluid at a temperature of,2600 F.

Example 6 V ide as determined by the method described in Example 1.

Example 7 An exothermic metallurgical composition in which titanium dioxide-was replaced by rare earth oxides and calcium-silicon was replaced by silicon metal was prepared by mixing 43 parts by weight of rare earth oxides (approximately 50% cerium oxide, the remainder being oxides of the other rare earth metals), 16.1 parts by weight of silicon metal, 19.4 parts by weight of sodium nitrate and 21.5 parts by weight of anhydrous sodium meta-silicate (NazSiOs). {On ignition this composition produced a product which absorbed 15 of its weight of titanium dioxide as.v determined by the method described in Example 1 and still: remained fluid at a temperature of 2600 F. 7

Example 8 i An exothermic metallurgical composition in which the metallic oxide was iron oxide in the form of magnetite (FeO.Fe2O3) was prepared by mixing 43 parts by weight a of magnetite, parts by weight of calcium-silicon and 27 parts by weight of sodium nitrate. On ignition this composition formeda product which when tested by the methoddescribed in Example 1 absorbed more than 20% of its weight of titanium dioxide and still remained fluid at 2600 F.

Example 9 An exothermic'metallurgical composition similar to' that described in Example 8 bu'thaving part of the calciumsilicon replaced by silicon metal wasprepared by mixing 43 parts by weight of magnetite, 21.5 parts by weight of calcium-silicon, 8.5 parts by weight of silicon metal and 27 parts by weight of sodium nitrate. composition produced a product which absorbed more than-20%of its weight of titanium dioxide and still re- W 7 Example I V p Another exothermicmetallurgical composition containing a mixtureof titanium dioxide, iron oxide and rare On ignition, this earth oxides as themetallic oxide was prepared by mixing 21.7 parts by weight of ilmenitefFeQTiOz), 23.3parts by weight: of rare earth oxides, 26.5 parts by weight of sodiurnnitrate, 20 parts by weight of silicon 'and.8.5 parts by weight of calcium-silicon. On ignition this composi tion. formed. a product which absorbed more. than 15% of its weight of titanium dioxide as determined by the method described in Example 1, and still remained fluid at 2600 A large amount of metallic alloy was also formed by-the exothermic reaction which occurred upon ignition of the exothermic composition. The composition was also prepared in the form of tablets in a manner similar to that described in Example 2.

Example 11 An exothermic metallurgical composition similarto that described in Example 10 was prepared by mixing 26 parts by weight of ilmenite, 18.5 parts by weight of rare earth oxides, 26.5 parts by weight ofsodium nitrate, 18 parts by weight of silicon, and 11 parts by weight of calciumsilicon. The absorption'capacity of the oxide product formed upon ignition of this composition was substantially the same as that for the composition of Example 10.

Example 12 Ingots of type 1015 carbon steel, weighing approximately 6 tons were manufactured in the usual manner except that prior to teeming the molten metal, 40' pounds of an exothermic metallurgical composition corresponding to that described in Example 5 were poured into each ingot mold, the interior of which had received no coating or other special treatment. .The metal was teemed in the usual manner and allowed to solidify. On removing the ingot from the mold during the stripping'operaition, it was observed that the surface of the ingot was covered with a substantially uniform glassy coating, indicating. that a sufficient quantity of slag had been presentrin the mixture and that this slag was sufiiciently fluid to coat the interior of the mold evenly. Beneath this glassy coating, the underlying surface of the metal was observed to be markedly improved with respect to cracks and scabs compared to similar ingots which were cast in coated molds but without the use of an exothermic metallurgical composition of this invention. Microscopic examination of cross sections of the ingot, which had been cast using the exothermic composition of the present invention, showed that it contained fewer oxide and sulfide type inclusions, and the form of the remaining inclusions was changed from chain type to themore desirable spherical type, compared with ingots cast in the conventional manner.

Other ingots similarly treated with.20, 40 and 60 pounds of a composition corresponding to that described in Example 2 showed comparable effects.

Example 13 mold it was found to be covered with a uniform glassy coating. The improvement of the underlying steel surface of the .ingot which had been cast using :this exothermic composition over ingots which were cast in the conventional manner was found to be even'more marked than in'Exa-mple. 12.

. Example 14 Example 13 was repeated using pounds of pellets of V the exothermic metallurgical composition described in Example The condition of the finished ingot was'cornparable to that. of the ingot which had been cast using an exothermic composition as described in'Example 13.

Example '15 Type 314 stainless steel was manufactured in the usual manner except that pellets of the exothermic metallurgical composition described in Example 3 were used in an amount corresponding to 15 pounds of pellets per ton of steel. The pellets were added to the molten steel while metals had been added to the steel by the exothermic reaction which occurred upon ignition of the exothermic composition. When an attempt was made to roll ingots which had been cast from steel which had not received the ladle treatment but which was otherwise identical to the steel described above, there was such extensive tearing of the metal that they could not be reduced from a cross section of inches square to a cross section of less than about 7-8 inches square.

Example 16 The experiment described in Example was repeated except that 15 pounds of pellets of the exothermic metallurgical composition described in Example 6 were added to the ladle. The behavior and condition of ingots which were treated with this composition were entirely comparable to the behavior and condition of ingots cast from steel which had been treated as in Example 15.

Example 1 7 A 2500 pound heat of type 321 stainless steel was treated in the ladle with 15 pounds per ton of pellets of the exothermic metallurgical composition described in Example 3. The treated steel was then cast into three 800 pound ingots. The metal molds in which these ingots were cast were treated as follows: In one mold 10 pounds of pellets having a composition corresponding to that described in Example 3 were placed. In the second mold 10 pounds of pellets having a composition corresponding to that described in Example 1 were added before teeming. No addition was made to the third mold. The ingots which had received mold treatment were found to be substantially smoother and more uniform than the ingot which was cast in the conventional manner. The ingots which had received the mold treatment were readily reduced by hot rolling from a cross section 11 inches square to a cross section 3 inches square in 8-10 passes and there was no evidence of tears or cracks caused by hot working. In contrast to this, the ingot which had been cast Without the use of an exothermic metallurgical composition of the invention in the mold showed edge cracking after it had been reduced only from a cross section 11 inches square to a cross section 8 inches square.

Example 18 An exothermic metallurgical composition was prepared by thoroughly mixing 51.8 parts by weight of ilmenite (FeO-TiOz), 30.2 parts by weight of milled calciumsilicon and 18 parts by weight of sodium nitrate. The softening point of the oxidic product obtained upon ignition of the composition was approximately 2050" F. The oxidic product absorbed approximately 15% of its weight of titanium dioxide as determined by the method described in Example 1, and still remained fluid at a temperature of 2600 F.

In view of the above, it will be seen that the several obiects of the invention are achieved and other advantageous results attained.

As various changes could be made in the above methods and products without departing from the scope of the invention, it is intended that all matter contained in the 10 above description shall be interpreted as illustrative and not in a limiting sense.

We claim:

1. An exothermic metallurgical composition comprising between approximately 10% and 43% by weight of titanium dioxide, at least approximately 10% by weight of a reducing agent for titanium dioxide and at least approximately 18% by weight of a source-of basic oxide, said composition forming upon ignition a product containing at least one acidic oxide, said product remaining fluid at a temperature of approximately 2600 F. after absorbing at least approximately 15 of its weight of titanium dioxide, said reducing agent and said source of basic oxide reacting upon ignition to reduce a substantial portion of the titanium dioxide to titanium metal.

2. An exothermic metallurgical composition in pellet form comprising between approximately 10% and 43% by weight of titanium dioxide, between approximately 10% and 30% by weight of a reducing agent for titanium dioxide and between approximately 18% and 28% by weight of a source of basic oxide, said composition forming upon ignition a product containing at least one acidic oxide, said product remaining fluid at a temperature of approximately 2600 F. after absorbing at least approximately 15% of its weight of titanium dioxide, said reducing agent and said source of basic oxide reacting upon ignition to reduce a substantial portion of the titanium dioxide to titanium metal.

3. An exothermic metallurgical composition comprising between approximately 10% and 43% by weight of titanium dioxide, up to approximately 23% by weight of rare earth oxides, at least approximately 10% by weight of a reducing agent for titanium dioxide and said rare earth oxides, and at least approximately 18% by weight of a source of basic oxide, said composition forming upon ignition a product containing at least one acidic oxide, said product remaining fluid at a temperature of approximately 2600 F. after absorbing at least approximately 15% of its weight of titanium dioxide, said reducing agent and said source of basic oxide reacting upon ignition to reduce a substantial portion of the titanium dioxide and the rare earth oxides to titanium metal and rare earth metals respectively. a

4. An exothermic metallurgical composition comprising between approximately 10% and 43% by weight of titanium dioxide, up to approximately 23% by weight of rare earth oxides, at least approximately 10% by Weight of a reducing agent for titanium dioxide and said rare earth oxides selected from the group consisting of silicon metal, silicon-zirconium, calcium-silicon, magnesiumaluminum, calcium boride, ferro-silicon, magnesium-containing alloys, magnesium metal, aluminum metal and mixtures thereof, and at least approximately 18% by weight of a source of basic oxide, said composition forming upon ignition a product containing at least one acidic oxide, said product remaining fluid at a temperature of approximately 2600 F. after absorbing at least approximately 15% of its weight of titanium dioxide, said reducing agent and said source of basic oxide reacting upon ignition to reduce a substantial portion of the titanium dioxide and the rare earth oxides to titanium metal and rare earth metals respectively.

5. An exothermic metallurgical composition comprising approximately 35% by weight of titanium dioxide, approximately 10% by weight of rare earth oxides, approximately 29% by Weight of calcium-silicon and approximately 26% by weight of sodium nitrate, said composition having an ignition temperature not greater than approximately 1300" F. and forming upon ignition a product containing at least one acidic oxide and at least one basic oxide, said product having a softening point not greater than approximately 2100 F. and remaining fluid at a temperature of approximately 2600 F. after absorbing at least approximately 15% of its weight of titanium dioxide, the.calcium-silicon and sodium nitrate reacting upon ignition to reduce a substantial'portion of the titanium'dioxide and the rare earth oxides 'to-titanium product having a softening point not greater than approximately 2100 F; and remaining fluid at a temperature of approximately 2600 F. after absorbing atleast approxi- .mately 15% of its weight of titanium dioxide, thecalciumsilicon'and sodiumnitrate reacting upon ignition to reduce a substantial portion of the ilmenite and the rare earth oxides to titanium metal and rare earth metals re-' spectivelyj t The method of casting a molten metal which comprises placing pellets ofan exothermic composition on the bottom of a mold, and then-teeming so that the molten metal falls'onto and ignites the pellets, said exothermic co'mpositibnfcomprising between approximately 10% and 4 3% by Weight of titanium dioxide, at least approximately 10% by Weight of a reducing agent for titanium dioxide 7 and at least approximately 18% by weight, ofa source of basic oxide, said composition forming upon ignition a product containing at least one acidic oxide, said product remaining fluid at a temperature of approximately 2600 F. after absorbing; at least approximately 15% of its Weight of titanium dioxide, said reducingagent and said source of basic oxide reacting upon ignition to reduce a substantial portion of the titanium dioxide to titanium metal. 7 8. In a method for the production of ferrous alloys,

the step of 'intermixing with a molten metal alloy an,

exothermic composition comprising between approximately 10% and 43% by weight of titanium dioxide, at least approximately 10% by Weight of a reducing agent for titanium dioxideand atleast approximately 18% by a '12 duce a substantial portionof. the titanium dioxide to titanium metal. I

9. In a method for the production of ferrousalloys, the step of adding to a ladle intowhich a molten ferrous alloy is tapped an exothermic composition comprising between approximately 10%. and 43% by weight of titaniumdioxide, up to, approximately 23% by weight of rare earth oxides, at least approximately 10% by weight of a reducing agent for the titanium dioxide and said rare earth oxides and at least approximately 18% by weight of a source of basic'oxide, said composition having an ignition temperature not greater than approximately 1300 F. andfforming upon ignition a product containing at least one acidic oxide, saidproduct having a softening point not, greater than approximately 2100" F. and remaining fluid at a temperatureofapproximately 2600 F. after absorbing at least approximately 15 %,,of its weight of titanium dioxide, said reducing agent and said source of basic oxide reacting uponf ignition to reduce a substantial portion of the titanium dioxide and,

the rare earth oxides'to titanium metal and rare earth metals respectively.

10.111 a method for the production of ferrous alloys, the step of adding to a mold into which a molten ferrous alloy is teemed an exothermic composition comprising between approximately 10% and .43% by weight of titanium dioxide, up to approximately 23% by weight of rare earth oxides, at least approximately 10% by weight of a reducing agent for the titanium dioxide'and said rare earth oxides and at least approximately 18% by weight of a source of basic oxide, said composition having an ignition temperature not greater than approximately 1300 F. and forming upon-ignition a product containing at least one acidic oxide, said product having a softening point not greater than approximately 2100 F. and remaining fluid at a temperature of approximately 2600" F. after absorbing at -least approximately 15% of its weight of titanium dioxide, said reducing agent and said source of basic oxide reacting upon ignition to reduce a substantial portion of the titanium dioxide and the rare earth oxides to titanium metal and rare earth metals respectively.

References Cited in the file of this patent UNi-TED STATES PATENTS 2,247,262 'Udy June 24, 1941 2,518,738 Woods et' a1. Aug. 15, 1950 2,683,662 Tisdale et al July 13, 1954 FOREIGN PATENTS 7 581,888 Great Britain Oct. 29, 1946

Claims (1)

1. AN EXOTHERMIC METALURGICAL COMPOSITION COMPRISING BETWEEN APPROXIMATELY 10% AND 43% BY WEIGHT OF TITANIUM DIOXIDE, AT LEAST APPROXIMATELY 10% BY WEIGHT OF A REDUCING AGENT FOR TITANIUM DIOXIDE AND AT LEAST APPROXIMATELY 18% BY WEIGHT OF A SOURCE OF BASIC OXIDE, SAID COMPOSITION FORMING UPON IGNITION A PRODUCT CONTAINING AT LEAST ONE ACIDIC OXIDE, SAID PRODUCT REMAINING FLUID AT A TEMPERATURE OF APPROXIMATELY 2600*F. AFTER ABSORBING AT LEAST APPROXIMATELY 15% OF ITS WEIGHT OF TITANIUM DIOXIDE, SAID REDUCING AGENT AND SAID SOURCE OF BASIC OXIDE REACTING UPON INGNITION TO REDUCE A SUBSTANTIAL PORTION OF THE TITANIUM DIOXIDE OF TITANIUM METAL.