Methods using high surface area per volume reactive particulate

Abstract

A method of processing finely divided reactive particulates (R.sub.Particulate) and forming a product comprising: providing a composite material comprising finely divided reactive particulates (R.sub.Particulate) dispersed in a protective matrix; at least partially exposing the finely divided reactive particulates (R.sub.Particulate); and forming the product.

Claims

1. A method of processing finely divided reactive particulates (R.sub.Particulate) and forming a product comprising: providing a solid composite material comprising (a) a protective matrix, (b) finely divided reactive particulates (R.sub.Particulate) dispersed in the protective matrix, and (c) at least one of (i) one or more metal compounds (MPCR) in one or more oxidation states, and (ii) a reductant (R), with the finely divided reactive particulates (R.sub.Particulate) having a particle size of up to 1 micron and the surface area to volume ratio of said finely divided reactive particulates (R.sub.Particulate) in said protective matrix being greater than 6 m.sup.2/mL, with the finely divided reactive particulates (R.sub.Particulate) comprising a metal or a metalloid selected from the group consisting of titanium, aluminium, vanadium, chromium, niobium, molybdenum, zirconium, silicon, boron, tin, hafnium, yttrium, iron, copper, nickel, bismuth, manganese, palladium, tungsten, cadmium, zinc, silver, cobalt, tantalum, scandium, ruthenium and the rare earths or a combination of any two or more thereof, and with the protective matrix comprising a metal halide (MRX) selected from the group consisting of MgCl2, NaCl, KCl, LiCl, BaCl2, CaCl2, BeCl2, AlCl3 and any combination thereof; at least partially exposing said finely divided reactive particulates (R.sub.Particulate) by subjecting said composite material to vacuum distillation, resulting in volatilisation of said matrix; and forming said product.

2. A method according to claim 1, wherein said composite material comprises up to 20 wt % of said reductant (R).

3. A method according to claim 1, wherein said composite material is in the form of particles.

4. A method according to claim 1, wherein said conditions result in sublimation of said matrix.

5. A method according to claim 1, wherein said vacuum distillation is conducted under inert conditions.

6. A method according to claim 5, wherein said inert conditions are under argon gas at a pressure of from 0.01 to 0.015 kPa.

7. A method according to claim 1, wherein said vacuum distillation is conducted at a temperature above the sublimation temperature of said protective matrix.

8. A method according to claim 1, wherein said finely divided reactive particulates (RParticulate) comprise at least titanium and said protective matrix comprises magnesium chloride and said vacuum distillation is conducted at a temperature of from 700 C. to 950 C.

9. A method according to claim 1, wherein said step of at least partially exposing said finely divided reactive particulates (RParticulate) comprises melting said matrix.

10. A method according to claim 1, wherein said step of at least partially exposing said finely divided reactive particulates (RParticulate) comprises milling, grinding and/or attrition of said composite material.

11. A method according to claim 1, wherein said step of at least partially exposing said finely divided reactive particulates (RParticulate) comprises treatment in a solid-solid, solid-liquid or solid-vapour contacting device.

12. A method according to claim 11, wherein said contacting device is a fluidised bed.

13. A method according to claim 1, wherein forming said product comprises exposing the exposed finely divided reactive particulates (RParticulate) to another material selected from the group consisting of titanium, aluminium, vanadium, chromium, niobium, molybdenum, zirconium, silicon, boron, tantalum, carbon, tin, hafnium, yttrium, iron, copper, nickel, bismuth, manganese, palladium, tungsten, cadmium, zinc, silver, cobalt, magnesium, beryllium, scandium, ruthenium and the rare earths or a combination of any two or more thereof.

14. A method according to claim 1, wherein said step of forming said product comprises at least one of redox reaction, non-redox reaction, agglomeration, alloying and cold-welding.

15. A method of processing finely divided reactive particulates (R.sub.Particulate) and forming a product comprising: providing a solid composite material comprising (a) a protective matrix, (b) finely divided reactive particulates (R.sub.Particulate) dispersed in the protective matrix, and (c) at least one of (i) one or more metal compounds (MPCR) in one or more oxidation states, and (ii) a reductant (R), with the finely divided reactive particulates (R.sub.Particulate) having a particle size of up to 1 micron and the surface area to volume ratio of said finely divided reactive particulates (R.sub.Particulate) in said protective matrix being greater than 6 m.sup.2/mL, with the finely divided reactive particulates (R.sub.Particulate) comprising a metal or a metalloid selected from the group consisting of titanium, aluminium, vanadium, chromium, niobium, molybdenum, zirconium, silicon, boron, tin, hafnium, yttrium, iron, copper, nickel, bismuth, manganese, palladium, tungsten, cadmium, zinc, silver, cobalt, tantalum, scandium, ruthenium and the rare earths or a combination of any two or more thereof, and with the protective matrix comprising a metal halide (MRX) selected from the group consisting of MgCl2, NaCl, KCl, LiCl, BaCl2, CaCl2, BeCl2, AlCl3 and any combination thereof; at least partially exposing said finely divided reactive particulates (R.sub.Particulate) by subjecting said composite material to milling, grinding and/or attrition of said composite material; and forming said product.

Description

BRIEF DESCRIPTION OF ACCOMPANYING DRAWINGS

(1) To further clarify various aspects of some embodiments of the present invention, a more particular description of the invention will be rendered by references to specific embodiments thereof, which are illustrated in the appended drawings. It should be appreciated that these drawings depict only typical embodiments of the invention and are therefore not to be considered limiting on its scope. The invention will be described and explained with additional specificity and detail through the accompanying drawings in which:

(2) FIG. 1 illustrates a flow chart of a method according to an embodiment of the invention.

(3) FIG. 2 is a SEM micrograph of microstructure of AgTi metallic material recovered in Example 4

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

(4) Hereinafter, this specification will describe the present invention according to the preferred embodiments. It is to be understood that limiting the description to the preferred embodiments of the invention is merely to facilitate discussion of the present invention and it is envisioned without departing from the scope of the appended claims.

(5) Referring to FIG. 1, a method 100 for forming a product through the exposure of finely divided reactive particulates (R.sub.Particulate) dispersed in a protective matrix is illustrated. The method involves providing a source of a composite material comprising finely divided reactive particulates (R.sub.Particulate) dispersed in a protective matrix 110. The composite material may be pre-treated 120 if desired, depending on the particular circumstances. For example, pre-treatment may comprise blending, compacting, milling or grinding of the composite material, provided this does not substantially expose the finely divided reactive particulates (R.sub.Particulate).

(6) The finely divided reactive particulates (R.sub.Particulate) of the composite material are at least partially exposed 130. This may include partially, predominantly or completely removing the protective matrix, or rendering the matrix temporarily permeable. The particulates are highly reactive and have a high surface area per volume. As such, exposure of the particulates, which may be through volatilisation of the protective matrix of the composite material (e.g. by vacuum distillation), melting of the matrix, milling, grinding and/or attrition of the composite material, treatment in a solid-solid, solid-liquid or solid-vapour contacting device (e.g. a fluidised bed), generally sets in motion the formation of the product.

(7) In its broadest form, the invention may provide a product formed from the finely divided reactive particulates (R.sub.Particulate) of the composite material. That is, through the agglomeration or alloying of the finely divided reactive particulates (R.sub.Particulate). The invention also considers the addition of another material 140, which may be a combination of other materials, prior to and/or during the exposure step 130. The other material(s) may be a material that takes part in a redox or non-redox reaction with the finely divided reactive particulates (R.sub.Particulate). It may clod-weld with the finely divided reactive particulates (R.sub.Particulate).

(8) Following the formation of the desired product, the product may be recovered 150.

EXAMPLES

(9) The following examples are provided for exemplification only and should not be construed as limiting on the invention in any way.

Example 1

(10) 25 g of composite material, black in colour, in finely ground particulate form comprising a matrix of magnesium chloride, titanium metal, magnesium and quantities of titanium sub-halides (TiCl.sub.2 and TiCl.sub.3) was mixed with a quantity of 6.9 g of Chromium tri-chloride (CrCl.sub.3), then placed in a vessel made from stainless steel. The vessel was placed under vacuum at a pressure of approximately 0.01 kPa. An argon purge was supplied at a rate of 10 mg/min. The vessel was then heated externally to a temperature of 900 C. at a heating rate of 31 C. per minute. The vessel was then left at a temperature of 900 C. for one hour before being cooled to room temperature.

(11) Under the prevailing conditions in this process titanium, chromium and chromium chloride would have been in solid phase.

(12) The vessel was purged with air and the remnant material was recovered from the vessel, comprising approximately 5 g of metal with a composition of 70% titanium-30% chromium. The metal was in the form of loosely sintered particles. The metal proportions observed represent a high extent of reduction of CrCl.sub.3 to metal by the finely divided titanium metal in the composite.

Example 2

(13) A reaction vessel made from stainless steel was purged with high purity argon and heated externally to 680 C. The system was charged with 500 g of titanium composite particles as a seed material. The system was allowed to reach an internal temperature of 675 C. At this point the component to be reduced was introduced.

(14) Vanadium tetrachloride was supplied at a rate of 50 grams per hour. The addition of the component to be reduced to the reactor increased the temperature in the reactor for a short period consistent with the exothermic nature of the reactions occurring at exposed reductant sites.

Example 3

(15) A reaction vessel made from stainless steel was purged with high purity argon and heated externally to 680 C. The system was charged with 500 g of titanium-aluminium composite particles as a seed material. The system was allowed to reach an internal temperature of 655 C. At this point reactant feeds were introduced.

(16) Titanium tetrachloride was supplied at a rate of approximately 150 grams per hour. The addition of the component to be reduced to the reactor increased the temperature in the reactor for a short period consistent with the exothermic nature of the reactions occurring at exposed reductant sites.

Example 4

(17) 20 g of composite material, black in colour, in finely ground particulate form comprising a matrix of magnesium chloride, titanium metal, magnesium and quantities of titanium sub-halides (TiCl.sub.2 and TiCl.sub.3) was mixed with a quantity of 7.4 g of silver chloride (AgCl), then placed in a vessel made from stainless steel. The vessel was placed under vacuum at a pressure of approximately 0.01 kPa. An argon purge was supplied at a rate of 10 mg/min. The vessel was then heated externally to a temperature of 900 C. at a heating rate of 31 C. per minute. The vessel was then left at a temperature of 900 C. for one hour before being cooled to room temperature.

(18) Under the prevailing conditions in this process titanium and silver would have been in solid phase, while silver chloride would have melted at 455 C. and remained in the liquid phase until consumed.

(19) The vessel was purged with air and the remnant material was recovered from the vessel, comprising approximately 8.35 g of metal with a composition of 60% silver-40% titanium. The metal was in the form of loosely sintered particles. The metal proportions observed represent a high extent of reduction of AgCl to metal by the finely divided titanium metal in the composite.

(20) FIG. 2 shows a SEM micrograph of the recovered material. A high degree of intermixing of the different metallic materials is evident and would be dependent on the degree of mixing prior to reaction.

Example 5

(21) 2 g of composite material, black in colour, in finely ground particulate form comprising a matrix of magnesium chloride, predominantly vanadium metal, magnesium and quantities of vanadium sub-halides was ground with a quantity of 0.4 g of Chromium tri-chloride (CrCl.sub.3). 50 mg of the ground material was then placed in an alumina cup and placed within a vacuum furnace. The furnace was placed under vacuum at a pressure of approximately 0.01 kPa. An argon purge was supplied at a rate of 2 mg/min. The furnace was then heated to a temperature of 900 C. at a heating rate of 10 C. per minute. The furnace was then left at a temperature of 900 C. for one hour before being cooled to room temperature.

(22) Under the prevailing conditions in this process vanadium, chromium and chromium chloride would have been in solid phase.

(23) The vessel was purged with air and the remnant material was recovered from the vessel, comprising approximately 12 mg of metal with a composition of 70% vanadium-30% chromium. The metal was in the form of loosely sintered particles. The metal proportions observed represent a high extent of reduction of CrCl.sub.3 to metal by the finely divided titanium metal in the composite.

Example 6

(24) 2 g of composite material, black in colour, in finely ground particulate form comprising a matrix of magnesium chloride, predominantly zirconium metal, magnesium and quantities of zirconium sub-halides was ground with a quantity of 0.4 g of Chromium tri-chloride (CrCl.sub.3). 50 mg of the ground material was then placed in an alumina cup and placed within a vacuum furnace. The furnace was placed under vacuum at a pressure of approximately 0.01 kPa. An argon purge was supplied at a rate of 2 mg/min. The furnace was then heated to a temperature of 900 C. at a heating rate of 10 C. per minute. The furnace was then left at a temperature of 900 C. for one hour before being cooled to room temperature.

(25) Under the prevailing conditions in this process zirconium, chromium and chromium chloride would have been in solid phase.

(26) The vessel was purged with air and the remnant material was recovered from the vessel, comprising approximately 12 mg of metal with a composition of 80% zirconium-20% chromium. The metal was in the form of loosely sintered particles.

(27) The metal proportions observed represent a high extent of reduction of CrCl.sub.3 to metal by the finely divided titanium metal in the composite.

(28) Unless the context requires otherwise or specifically stated to the contrary, integers, steps or elements of the invention recited herein as singular integers, steps or elements clearly encompass both singular and plural forms of the recited integers, steps or elements.

(29) It will be appreciated that the foregoing description has been given by way of illustrative example of the invention and that all such modifications and variations thereto as would be apparent to persons of skill in the art are deemed to fall within the broad scope and ambit of the invention as herein set forth.