BENEFICIATION OF ASTEROIDAL MATERIALS IN SPACE
Richard M. Westfall
Galactic Mining
Industries, Inc.,
spaceguy2008@aol.com 719-930-3161
William C. Jenkin - G_d Rest His Glorious Soul
Galactic Mining
Industries, Inc.,
Forever Missed and Loved
George Hansen and Matthew Pettit
Metal Matrix
Composites Company,
gchansen@xmission.com 435-654-3683
ABSTRACT: This paper discusses proposed experiments on Earth and in Earth orbit designed to show the utility of the Carbonyl Process in the beneficiation of Asteroids in space. Stony/Iron and Iron Asteroids are the target bodies for this beneficiation processing. We propose the use of these asteroidal metals in the manufacture of pressure vessels, structures, housings, framing networks, reflectors and other components necessary for the production of an in-space infrastructure. We propose on-Earth experiments involving the carbonyl digestion of nickel and iron metals from meteorites, and subsequent use of nickel carbonyl or iron carbonyl gas to form metal or metal/fiber composite components using CVD (Chemical Vapor Deposition). These experiments on-Earth will be followed by the launch of small payloads, which will show the efficacy of the process in a zero gravity environment such as near Earth orbit. Results from these experiments will be used to scale up to industrial capacity in space. Iron carbonyl is of great importance as the major component of the metallic fraction of asteroids is iron, however due to the much greater expertise and ease of chemistry, this work will focus only on the nickel carbonyl processes.
The experiments planned herein involve the following general steps:
1. Acquisition of meteoric materials of either the stony/iron or the iron type.
2. Pulverization of the meteoric materials to a finely divided form, via either mechanical, ultrasonic or other methods.
3. Magnetic separation of the metallic fraction from the stony fraction of stony/iron meteorites. Solid iron meteorites are rare when compared to the stony/iron variety and need no magnetic separation.
4. Insertion of the metallic fraction into a suitable digestion chamber wherein the digestion of the metals will occur. This is a low temperature/atmospheric pressure process, thus reducing the expensive conventional high energy and high pressure or vacuum processes generally related with metal beneficiation.
5. Separation of nickel carbonyl from iron carbonyl.
6. Transport of nickel carbonyl to the inside of a suitably shaped inflatable mandrel wherein heating of the inflatable skin results in the CVD deposition of a nickel metallic coating.
7. In addition to CVD on mandrel surfaces, in-situ chemical vapor infiltration (CVI) of fiber preforms, results in a metal matrix composite; a form of composite superior to conventional composites in the rigors of the space environment.
8. Testing of the resultant nickel or nickel/fiber composite components for mechanical and other characteristics. Testing on Earth will be more extensive than those done in space.
Galactic Mining Industries, Inc. is a
William Jenkin, George Hansen and Matthew Pettit bring a cumulative 76 years of hands-on expertise in nickel carbonyl processing and composite technology to the team . CVD coatings of inflatables and mandrel surfaces and CVI fabrication of metal composites are done by this talented team of people.
NICKEL CARBONYL METALLURGY IN SPACE
FOR USE IN THE
PRODUCTION OF A SPACE INFRASTRUCTURE
By: Richard Westfall
Galactic Mining Industries, Inc.
This paper examines carbonyl metallurgical processes and their applicability to space manufacturing. Manufacture of a space infrastructure using in-situ materials found in space is a very important goal for the commercial viability and rapid progress of space colonization efforts. The metallic fraction of near earth asteroids is made up of iron, nickel, cobalt and high concentrations of platinum group metals. Use of this metallic fraction is discussed in this presentation.
Galactic Mining Industries, Inc. of
This paper is presented as a summary of carbonyl metallurgy that has been gathered by Galactic Mining Industries from sources such as Bill Jenkin and George Hansen of Metal Matrix Composites Co. After the summary section, papers by Bill Jenkin and George Hansen are presented in order to preserve their original content and to give the reader an idea of where the individual areas of expertise lie.
The carbonyl metallurgical processes are Chemical Vapor Deposition (CVD) processes. Metals such as nickel are digested by exposure to carbon monoxide (CO) gas under controlled conditions. The resulting nickel tetracarbonyl (Ni(CO)4) is transported to the inside of a suitably shaped inflatable, to the surface of a mandrel or infiltrated within a fiber perform, wherein the nickel tetracarbonyl comes in contact with a heated surface. Upon contact with a heated surface, the nickel tetracarbonyl decomposes to produce a chemical vapor deposited nickel metal coating.
Carbonyl
digestion:
The chemical equation for the carbonyl digestion of nickel metal is as follows:
Ni + 4(CO) - Ni(CO)4(gaseous molecule)
In this reaction, nickel metal is digested by the exposure to carbon monoxide, producing nickel tetracarbonyl (Ni(CO)4). This reaction is preferably done at near 75 degrees Celsius at virtually all pressures.
Digestion conditions for Ni + CO to produce Ni(CO)4, range from 60 psi CO carbon monoxide overpressure to 200 psi CO overpressure, at a temperature of 75 degrees C. INCO uses fluidized bed technology at 1000 psi CO overpressure to extract nickel in mining operations.
Carbonyl
decomposition:
Nickel tetracarbonyl is usable as a Chemical Vapor Deposition (CVD) reagent. When the gaseous nickel tetracarbonyl comes into contact with a heated surface, a nickel coating is the result of the decomposition of the nickel tetracarbonyl. The deposition of nickel from the gaseous molecule (nickel tetracarbonyl) is the reverse reaction of the digestion:
Ni(CO)4 + heat – Ni(metallic coating) + 4(CO)
This decomposition occurs between 35 and 300 degrees C, with optimal results at 175 degrees C or greater, when coating forms. As in other equilibria reactions, the temperature of the nickel tetracarbonyl decomposition is increased with increasing carbon monoxide overpressure. As little as 1% nickel tetracarbonyl content in an atmosphere of carbon monoxide can be a useful CVD gaseous composition.
Near Earth
Asteroids as raw materials sources:
The digestion of the metal fraction of stony-iron Near Earth Asteroids involves more complex chemistry than the simple digestion/deposition of nickel metal.
The metallic fraction of stony-iron Near Earth Asteroids is a mixture of the following metals: Fe (iron), Ni (nickel), Co(cobalt), Pt(platinum), Pd(palladium), Ir(iridium), Rh(rhodium) and other metals. The use of the carbonyl digestion process involves the extraction/volatilization of metal carbonyl molecules. Iron is digested by carbon monoxide to produce Fe(CO)5 iron pentacarbonyl, while the nickel is converted to Ni(CO)4 nickel tetracarbonyl. The iron pentacarbonyl is not as developed as a CVD process to produce coatings, making the iron pentacarbonyl less desirable in the early stages of space industrialization. Likewise, the cobalt octacarbonyl is readily useable in the production of CVD coatings. Luckily the volatilization characteristics of Fe(CO)5 iron pentacarbonyl; Ni(CO)4 nickel tetracarbonyl and, {Co(CO)4}2 cobalt octacarbonyl are sufficiently different to allow for their selective condensation and separation.
The boiling points for the following molecules are as follows:
Fe(CO)5 - 102.8 degrees C,
Ni(CO)4 - 37 or 43 degrees C, depending on reference used,
{Co(CO)4}2 - very high temp, >> than Fe(CO)5 temp., also known to decompose @ 52 degrees C.
It can be seen that the nickel tetracarbonyl has the highest vapor pressure, and can be separated to give high-purity nickel tetracarbonyl for deposition uses. The iron and cobalt carbonyls are used in other metallurgical work and will be developed into future CVD source materials. The platinum group metals are digested in the carbonyl gas stream by the addition of halides (F2, Cl2, Br2, I2), to produce metal-carbonyl-halide molecules. The platinum group carbonyl halide molecules are used in other metallurgical processes. The platinum group metals have a very high terrestrial value and can be used as currency and collateral in the financing of the development of a space industrial infrastructure.
Boron
strengthened nickel coatings:
In an expired patent by Bill Jenkin, the inclusion of diborane in the nickel tetracarbonyl gas stream produces an alloy coating of nickel/boron. The resultant boron-hardened nickel coating shows an increase in strength to 200 Kpsi tensile strength, with a Rockwell Hardness value of 40 to 50. Steel is between 50 KPSI to 60 KPSI in tensile strength. Nickel (without boron) deposited from nickel tetracarbonyl has tensile strength in the range of 80 to 90 Kpsi, and a Rockwell Hardness of 10 to 20. The Ni/B alloy strengths lend themselves to the production of pressure vessels, habitats, framing networks, framing mesh systems, mirrors, and other structural components required for the construction of on-orbit habitats and space stations with and without artificial gravity.
Pressure vessels made with the boron-hardened Nickel coating, can have thinner walls when compared to pressure vessels made of other materials. This manufacturing advantage in component strength/mass ratio will be very important in the manufacture of habitats and industrial capacity in space.
Inflatables
as forms:
Inflatables and mandrel forms will be used in making space stations and space industrial infrastructure components. These forms provide shaped/heated surfaces for the exposure to nickel tetracarbonyl, wherein, Chemical Vapor Deposited (CVD) coatings of nickel and its alloys, produce components.
Fiber
performs as substrates for making metal matrix composites:
George Hansen and his company Metal Matrix Composites bring to the team the expertise to make metal matrix composites. Carbon graphite fibers are infiltrated with nickel carbonyl to produce nickel/graphite composites which are especially well suited to the space environment. George’s paper appears later in the paper.
Proposed
experiments:
We propose experimental setups which will examine processing meteorites found on earth. The processing will involve the steps listed in the Abstract. We will purchase stony/iron meteorites and process them to yield powdered (200 mesh) metallic fractions. These powdered metals will be put in digestion chambers and carbonyl digestion will be performed. We will look at the resultant volatile metal carbonyls and their separation into individual components. The isolated nickel volatile content will be used to deposit coatings of nickel and to form metal composites. The resultant materials will be examined for physical properties such as density, mechanical strength, elemental composition and other properties.
The information derived from such experiments will be applied to the design of “get-away” special payloads, which can be inserted into orbit. Such experimental satellites will be launched with stony/iron meteoric materials to determine the efficacy of such processes in zero gravity conditions. Pulverization will probably be done on Earth for the first phase of this work, as pulverization equipment will probably be prohibitively expensive to launch as a payload hitching a ride on available satellite launches.
Telepossession probes as proposed by the company will use the technology devised from this work to assist in the establishment of title to target asteroids. Title to asteroids will be used as leverage in financing of the commercialization and colonization of space.
A PROPOSED METAL FORMING PROCESS FOR
FABRICATION IN SOLAR SYSTEM SITES
By William C. Jenkin
Metal forming processes with features attractive to structural metal fabrication operations in space using in-situ materials stocks are not well developed. The described nickel carbonyl processes prominent attractive features are that it does not require massive equipment such as a blast furnace, rolling mill, foundry or extensive machinery, etc. A further advantage is that it can be activated by solar heat or by electricity from photovoltaics and/or thermoelectric generators. It does not use consumable fuels.
Description
This process is chemical vapor deposition (CVD) of nickel. First discovered in 1905, it has languished because it is toxic and has lacked a pioneer to develop production technologies as well as lacking good commercial application. In the world of CVD, Chemical Vapor Deposition of nickel is in a class by itself and is to be distinguished from all other CVD such as aluminum, titanium or carbon.
¨ It does not use high temperatures or pressures;
¨ It does not require massive equipment;
¨ It is a recyclable system;
¨ It produces the common, strong, ductile, corrosion-resistant, versatile metal, nickel.
A one-sentence description of the process is: an easily volatile intermediate compound of nickel is formed at one point and pumped to another point where the vapors are distributed over a mildly heated surface, decompose thereon, and deposit structurally sound nickel.
In simple terms, an intermediate nickel compound (nickel carbonyl), is formed by reacting carbon monoxide gas with nickel or nickel iron powder at Point A, is then transported to an enclosure and reacted with a heated surface at Point B to make a nickel metal form. Only low pressures are required.
The primary metal produced (nickel) is a useful structural metal with good ductility and strength better than cold rolled steel.
Operation
The operation is proposed to be carried out on a nickel or nickel iron based asteroid, or upon a sun-radiated solar space station.
Accessories required are:
I. To produce chemical intermediate:
1. An extensive source of electric power from solar generators.
2. The ore must be excavated from the asteroid surface.
3. It must be ground to 200 mesh or thereabouts.
4. A reactor to make the chemical intermediate is needed.
5. Storage cylinders are needed.
6. A supply of carbon monoxide gas is required. The carbon monoxide will be recovered after the deposition, re-circulated and reused.
II. General Needs:
1. A supply of an inactive gas may be required (such as nitrogen).
2. More solar photovoltaic or thermoelectric generators are required.
3. Vacuum pumps are required.
4. A Compression Pump is required.
5. Transfer pumps are required.
6. Enclosures for deposition to make required parts are required. They must withstand only low pressures.
7. Mandrels on which to deposit metal are required. These will be of a type to use repeatedly to form requested parts. Deposition can be on an external form or on the inside of a suitable mandrel.
8. Heat required must be obtained by infrared reflectors to capture sunlight heat. This will require innovative engineering.
9. Means to capture used gases is required.
NOTE: No heavy equipment is required except perhaps pulverizing equipment.
Unique
Features of Nickel CVD
One cannot emphasize enough the superiority of nickel CVD for use in solar system sites over all other CVD methods. Once again:
¨ Nickel CVD is a ductile, strong and rust-free metal.
¨ Nickel CVD is low temperature fabrication. Deposition temperatures average 175° C; b,p of intermediate, volatile compound is 43°C.
¨ Nickel CVD has a wide range of permissible concentration of intermediate vapor in vapor streams directed at deposition.
¨ The Nickel CVD intermediate chemical compound is easily recyclable.
With Nickel CVD a wide variety of mechanical set ups are available.
Historical Development
NICKEL FORMING CVD TECHNOLOGY FROM 1950 TO 2002
Production of
Nickel CVD forms in the lab was initiated in 1950 at Commonwealth Engineering
Company of
Serious continuous development of the process began in 1958 when William C. Jenkin joined Commonwealth Engineering Company under a program sponsored by Union Carbide Development Company. Technology was developed to produce nickel forms of exceptionally uniform thickness. The technology that was developed produced shells that had exceptionally well filled internal corners and recesses fantastically superior to any other metal deposition process. Moreover, external corners and projections did not develop exaggerated or modular growth.
By 1964,
desirable, continuously repetitive and production oriented applications still
had not been discovered. The sponsor,
Union Carbide, attempted to continue a search for applications in
The uniform thin (1/8”) shells produced aroused interest in the tooling industry because the 1/8” very uniform shells could be backed with epoxy type resin structures and used for RIM (Reaction Injection Molding), a low pressure polyurethane molding process used to make automotive parts (fascia). It was also proposed to make shells for rotational molding of plastics because the uniformity was so good CVD shells would have several times longer life than conventional cast aluminum or electroplated shells.
The first
tooling manufacturing facility was set up by Jenkin in 1968 at Akron Standard
Mold in
Operations
continued in the
In 1995, a
nickel shell CVD forming facility was set up in
INCO Ltd., of
COMPARISON OF CVD OF
NICKEL VS IRON PLUS PROPOSED
By William C. Jenkin
From a practical standpoint, existence of nickel or iron carbonyls other than the tetracarbonyl of nickel or pentacarbonyl of iron is fleeting and can only be found in academic studies with such equipment as a mass spectrophotometer. Of theoretical chemical interest, however, is the fact that carbonyl groups (ligands) can be individually replaced by other ligands, such as –NO (nitric oxide) or amino groups such as trimethyl amine, or –CF3 (trifluorophosphine), or sulfur bearing ligands, such as –HS or –SH(CH3)2. In CVD, only the latter are of interest, as use of H23 or carbonyl sulfide has a catalytic effect both on formation and decomposition of carbonyl, particularly nickel carbonyl.
It has been documented that the basic CVD reaction is the absorption of the metal carbonyl molecule on a heated substrate surface, then decomposition occurs and releases the carbon monoxide, which escapes. Under favorable conditions, the metal atom enters the crystal lattice of the substrate yielding a crystalline full strength deposit. Under unfavorable conditions, the deposit may be amorphous and of varying strength, carton content, and brittleness.
Nickel Carbonyl
Nickel carbonyl (b.p. 43° C) is an exceptional CVD precursor because the deposit at temperatures not far from 175° C, contains very low carbon, such as a maximum of .02%. . Forms and shapes are commonly created from a vapor stream of 90% carbonyl and 10% carbon monoxide. With this 10% carbon monoxide addition, leveling of deposits and corner filling are absolutely phenomenal.
Iron Carbonyl
Iron carbonyl (b.p.
103°C) as a CVD precursor is far different.
Immediately on decomposition, the carbon monoxide released inhibits and
restricts further decomposition. Whereas
the initial decomposition temperature is 190° C, temperature must be increased
to achieve deposition, causing the deposit to acquire much carbon and to be
very amorphous and brittle. Carbon
content is typically around 10% directly from the carbonyl.
Only a limited amount of research time has been invested to circumvent this problem. No published data presents a good deposition system, as of 1990. The author, in 6 months of part time research and after scattered attempts over 30 years, has come up with a deposition system that consists of vaporizing iron carbonyl in a stream of half carbon dioxide and half water vapor. The carbon content of the deposit is 1%. The deposit is moderately brittle, not horribly. An anneal will reduce brittleness to a tolerable level. Only thin deposits .001” thick have been made so far, not heavy ones.
In nickel CVD
production systems, carbon monoxide as a carrier is attractive because only one
gas is dealt with. It offers good
control and the byproduct from the deposition system is only carbon monoxide,
which is easily recycled to make more nickel carbonyl. Such a system is well-researched and tested
in production.
With the best known systems proposed for iron CVD, the exhaust consists of carbon dioxide and water vapor, plus carbon monoxide from the decomposition. Now when these exchange gases are recycled, it is unknown how this compressed gas mixture will react with metal powder to make carbonyls. Most of the water vapor will be condensed and removed, so the compressed gases are mostly the carbon oxides with a little water vapor.
Since the carbon dioxide and small amount of water vapor do not react with a metal powder, perhaps the carbonyl synthesis will proceed smoothly.
Synthesis of iron
carbonyl by direct compression and reaction with carbon monoxide is not as
simple as the same reaction to make nickel carbonyl. Normally, a higher pressure is required. In
The above discussion refers to production of carbonyl from either nickel or iron powder.
What must be explored is the direct production of the mixed carbonyls from the nickel iron powder as mined from an asteroid. Chemically, I would expect a direct synthesis reaction (with for example 50-50 nickel iron powder) from these gases to produce a carbonyl mix high in nickel carbonyl. Let’s guess that 80% of the carbonyl is nickel carbonyl. Then, when CVD is performed with this mix, the carrier gas mix chosen should be the one that works for iron CVD – namely the carbon dioxide-water vapor mix. All the nickel will be expected to deposit, plus half the iron. Unreacted gases will be recycled. Thus the deposit would be an alloy of 90% nickel, balance iron.
With this type CVD, iron carbonyl is not wasted. With a carbon monoxide carrier gas system as used for nickel CVD, nearly 100% nickel carbonyl would be expected to be deposited and the iron carbonyl will be wasted.
There could be an unexpected chance that this
does not happen, that a higher temperature than normally used for nickel CVD
with carbon monoxide will produce better deposits than produced from a carbon
dioxide-water vapor system.
Deposits would be of lower quality than from the carbon monoxide system at 175° C, but possibly better than those from the carbon dioxide-water vapor system. And only carbon monoxide gas has to be recycled.
Problems
Problems to be researched summarize as follows:
1) What pressure is required to synthesize carbonyls from the nickel-iron powder on an asteroid. Hopefully, it is much less than the 1000 psi or more normally used to make iron carbonyl.
2) Which mix can be used for CVD: the carbon monoxide carrier gas system or the carbon dioxide-water vapor system. Hopefully, the former
3) Obviously, how to excavate the mineral and grind it to 200mesh.
4) Obviously, the mixed power system will consist of a solar photovoltaic electrical system with a solar thermal energy reflector system for process heat.
The kind of building structure that I hear Westfall talk about is metal-walled structure produced by CVD. In the past, I have thought of making tinker-toy like forms, and I stretch plastic films over them.
The CVD problems with making metal-walled structures are enormous. However, as I write this, I have thought of a way that might be considered. Let’s consider that only spherical structures can be considered, as the shape that can stand the highest pressure for the volume involved. Everything would be based on igloo-like structures.
A half-sphere might be produced from a mold like this:
|
|
Solar radiation |
|
|
CVD deposit |
|
Wall of mold Base of mold |
|
|
Bottom surface unheated & insulated |
|
|
Multiple structures formed: |
|
· Use: join 2 to make a sphere or place on flat base. Sphere is better for withstanding pressure.
o Limit size: 8, 10 or 12 ft. diameter, etc.
o Tubular connections between multiple spheres to be engineered.
· Pressure of internal atmosphere to be decided; astronauts use 5 psi.
William C. Jenkin
Manufacturing of Metal Matrix Composites
Through In-Situ Chemical Vapor Infiltration of Fibers or Fiber Pre-forms
George Hansen
Metal Matrix Composites Company
Much of the discussion to this point has centered on the direct chemical vapor deposition of solid nickel and/or iron thick walled forms, derived from their carbonyls originating from carbonylation of asteroidal materials. In space, where gravity is of less concern and asteroidal materials are presumably abundant, the strength to weight ratios that are of normal concern in gravity flight are somewhat reduced in importance. Thus, many objects could be fabricated from the pure bulk metals, as previously described.
However, in many space or extraterrestrial gravity applications, there will still be a great need for high strength, low weight or high stiffness, low specific volume materials. Such will be the role of fiber reinforced composite materials. Lightweight fiber reinforcements of carbon or ceramics have long been notable design engineering materials used to create desirable anisotropic mechanical, electrical or thermal properties. In conventional composite systems, the matrix holding the stiff fibers in place is usually a polymeric thermo set or thermoplastic resin. However, in space systems, such organic matrices are highly limited in their use. This is for two primary reasons. First, all of these organic materials originate from the earth, and thus would be required to be transported from earth, along with the ancillary processing equipment. Secondly, organic materials do not fare well in space environments, particularly in the presence of atomic oxygen or other ionized or high-energy particles and certain types of radiation.
A good method of creating an engineered composite for space applications would be to create a metal matrix composite. This can be done by performing the described CVD processes in the presence of a preform of fibers. This process is often referred to as ‘chemical vapor infiltration’ (CVI).
There are several successful CVI systems to point to as examples of the usefulness of the technology. For instance, the fabrication of carbon/carbon or carbon/silicon carbide composite systems uses high temperature CVI as the basis of their production. Metal infiltration of open cell foams is another example.
This section will describe the application of nickel CVI as a tool to create a nickel/carbon fiber composite. One method by which this may be accomplished is by simply allowing the nickel form CVD to proceed in the presence of a pre-engineered form of fibers - usually called a ‘pre-form’. As the fibers would need to be transported from earth, it would be judicious to learn to use such composites in applications where the use of the locally available bulk reformed asteroidal material simply will not meet the desired engineering objectives in the pure form; or in applications where the directional strength and stiffness of the fibers will yield a decided advantage.
One potential problem with the direct CVI of preforms might be the complete and uniform infiltration and consolidation of the composite. However, in many applications, the fibers are the primary load bearing members and the matrix is simply the stiffening phase. In more critical applications of a true composite, wherein the fibers and the matrix both share and transfer the loads, the uniform infiltration and consolidation of the matrix is more important.
There are many methods, both primary and secondary, to ensure matrix consolidation. A primary method is the simple ensurance of proper processing conditions and quality control. An example of a secondary method is as follows.
If minor amounts of aluminum are deposited into a nickel/fiber system, then the resulting composite can be subsequently reactively sintered and pressed to a very high strength and lightweight metal matrix composite. The pressures and temperatures to achieve this complete consolidation are much lower than would be required by conventional thermo-mechanical means, such as hot pressing or rolling. The reason for this is that as the composite is heated to a point approaching the melting point of the aluminum, the aluminum starts to rapidly diffuse into the nickel. These two elements then reactively combine to create nickel aluminide. This reaction is highly exothermic, so much so that the heat of reaction supplies the rest of the energy required to heat the matrix to a plastic or liquid state. During this brief period, moderate pressures will result in the complete consolidation of the composite. After the reaction is complete, the part then rapidly cools back to a fully stiff and solid composite.
These metal matrix composites have stiffness and strength to weight ratios that are better than titanium. The aluminide nature of the composite permits the materials to retain its excellent mechanical properties to well over 500 degrees C.
An electron micrograph of such a metal matrix composite is shown below. This is only one of many examples of a metal matrix composite; but it is one whose manufacturing process lends itself to space or asteroidal beneficiation.
Typical Fracture Surface of NiAl Carbon Fiber Composite
