AU2018101150B4

AU2018101150B4 - This patent application is a description of an extraction process which maximises resource utilisation by extracting valuable molybdenum oxides from overburden developed by oxidation processes above a metal deposit. The product of this process is then utilised as components of molybdenum trioxide - based fertiliser.

Info

Publication number: AU2018101150B4
Application number: AU2018101150A
Authority: AU
Inventors: Garry Alexander Edser; Gregory Thomas Paynter; Kristine Jane Starr
Original assignee: Kynoch Minerals Pty Ltd
Current assignee: Kynoch Minerals Pty Ltd
Priority date: 2018-08-13
Filing date: 2018-08-13
Publication date: 2019-01-17
Anticipated expiration: 2026-08-13
Also published as: AU2018101150A4; AU2018101150C4

Abstract

This patent application is a description of an extraction process which maximises resource utilisation by extracting valuable molybdenum oxides from overburden developed by oxidation processes above a metal deposit. By use of physical extraction utilising gravity separation post-treatment of crushing the raw rock material, refined molybdenum trioxide can be added to composted material to increase the efficacy of the product for plant uptake. Molybdenum Oxide has vast potential as a fertiliser product, particularly due to its role in nitrogen metabolism, and the synthesis of protein in plants. Molybdenum is one of the essential micronutrients that acts as a catalyst required by plants and symbiotic bacteria in order to make nitrogen plant-available.

Description

THE MANUFACTURE OF MOLYBDENUM FERTILISER

FIELD OF THE INVENTION [001] This is an extraction process which maximises resource utilisation by extracting Molybdenum Oxides from overburden above a metal deposit. The extracted material can be used for a component of trace element fertiliser.

[002] The innovation revolves around the extraction of molybdenum trioxide from the oxidised overburden referred to in Claim No 1. This overburden is ore. This material can be used to make molybdenum metal based products without the need for industrial chemical processing to make the source material, from which we extract molybdenum based products.

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BACKGROUND TO THE INVENTION [003] In order to make commercial grade fertiliser material the production process will continually improve the grade or purity of the Oxide source rock from 0.5% MOO3 in the run of mine ore (ROM) to a significantly more refined grade of 90% MOO3. ROM is mined ore that is ready for processing.

[004] Molybdenum Oxide can occur naturally (but rarely) as the yellow crystalline mineral molybdite (MOO3).

What [005] Although it is toxic in anything other than small quantities, Molybdenum is an essential element for animals and plants. There are about 50 different enzymes used by plants and animals that contain Molybdenum. One of these is nitrogenase, found in nitrogen-fixing bacteria that make nitrogen from the air available to plants. Leguminous plants have root nodules that contain these nitrogen-fixing bacteria.

2018101150 17Aug2018 [006] By use of physical extraction utilising gravity separation posttreatment of crushing the raw rock material, refined Molybdenum trioxide can be added to composted material to increase the efficacy of the product for plant uptake. This increases resource utilisation efficiencies and also improves soil nitrogen cycling via ecosystem functions of nitrogen fixing bacteria. In addition it improves energy use cost due to not having to produce the nitrogen via the Haber Bosch methodology. Note that this process is registered for use in organic farming practices and will be compliant as such to the National Standard for organic and biodynamic products (Version 3.7) and the Australian Standard AS 6000 which is a component of Standards Australia.

How [007] We assume that the reader has a working knowledge of chemical terms such as element, ion, compound, molecule, mineral, oxidation. Molybdenum (atomic weight 95.96) is a shiny grey coloured metal element used extensively in the steel industry.

[008] The upper part of the Earth's crust has developed over millions of years by interacting with water and atmospheric gases, all of which contain oxygen and which react with reduced elements in compounds such as the metal sulphides and common rock forming silicate minerals. This is why we see brown coloured rocks at the surface and grey coloured rock cores brought up from depth (30 metres below ground level) by drilling rigs. Whether this redox interface between oxidised rock and unoxidised (fresh) rock is at 30 or 50 metres etc. depends on many factors such as climate history, soil development and type, geological history etc. The other important factor is that much groundwater movement occurs within this weathered or oxidised zone.

2018101150 17 Aug 2018 [009] Within the oxidised zone grey molybdenite (M0S2) is converted to the yellow trioxide molybdite (MOO3).

[010] The current methodology for making oxides of Molybdenum is based on deriving the oxide from the sulphide metal ore. This process has high externalities associated with it. All current Molybdenum Oxide production is a by-product of metal refining and no dedicated primary extraction of Molybdenum Oxide exists. The next paragraph details aspects of the chemistry underlying the current paradigm.

[Oil] The anions (negatively charged ions) which are of importance as plant nutrients are molybdate MoO4(2-). However to meet industrial demand sodium and ammonium molybdate are traditionally made in China and the USA by a complex energy and chemical demanding process. Sodium molybdate is made by roasting in a caustic (alkali) environment.

2MOS2+7O2—>2Mo+4SO2t,

MoO3+2NaOH+H2O^Na2MoO₄-2H₂O.

Equation 01 [012] Ammonium Molybdate is made by roasting then ammonia leaching, purification and reaction with nitric acid. After separation, drying and sieving one can obtain the finished product.

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Who/Why [013] Molybdenum Trioxide has vast potential as a fertiliser product, particularly due to its role in nitrogen metabolism, and the synthesis of protein in plants. One of the largest crop types in the world of agriculture are legumes or pulses, which provide a plant-derived form of protein that is not sourced from animals. Molybdenum Trioxide assists in nitrogen uptake by legumes in particular, and in crops in general. Molybdenum Trioxide fertiliser can be added to the soil, or directly to the plant.

[014] Molybdenum is one of the essential micronutrients required by plants and symbiotic bacteria. Molybdenum is important in nitrogen metabolism. Of all the essential micronutrients, Molybdenum is required in the smallest amount by plants. Symbiotic bacteria however, require approximately ten times more Molybdenum for nitrogen fixation than the host plant. If there is not enough Molybdenum present, petro-chemical based fertilisers are required to accommodate for this and provide the required amount of nitrogen.

[015] Molybdenum is the least abundant of the trace elements in soils, and only a small amount is present in forms that are available to plants. Molybdenum fertiliser is therefore necessary to ensure plants have the essential micronutrients to convert destructive nitrates into protein. Our invention represents a cleaner alternative to the traditional method noted below. It is also compliant to be registered for use in organic farming systems.

2018101150 17Aug2018 [016] Compounds mimicking the enzyme nitrogenase represent promising alternative routes to the current Haber-Bosch industrial synthesis of ammonia from molecular hydrogen and nitrogen (Leigh, 2003). Noting the reduction of embedded energy due to the fostering of ecosystem services provided by the symbiotic processes in the rhizosphere of legume plants. Note also that 74,000 tonnes of N2 is in the air above every hectare of land. Molybdenum acts as a catalyst to enable ecosystem functions to make it plant-available, hence reducing the downsize externality and embedded energy costs of the Haber-Bosch process inflicts on the environment and society.

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SUMMARY OF THE INVENTION [017] The following article extract in the next two paragraphs (018/019) is from (Hoffman, 2014). Individual citations at the end of each sentence in

Hoffman's paper will not be repeated here.

[018] Nitrogen fixation has a profound agronomic, economic, and ecological impact owing to the fact that the availability of fixed nitrogen represents the factor that most frequently limits agricultural production throughout the world. Indeed, nearly half of the existing human population could not exist without application of the Haber-Bosch process (Leigh, 2004) for production of nitrogen fertilizers. Given that over half of the fixed nitrogen input that sustains Earth's population is supplied biologically, there has been intense interest in understanding how the nitrogenase enzyme accomplishes the difficult task of N2 fixation at ambient temperature and pressure. An understanding of biological N2 fixation may further serve as the foundation for achieving two highly desirable, although so far unmet, goals: genetically endowing higher plants with the capacity to fix their own nitrogen and developing improved synthetic catalysts based on the biological mechanism.

2018101150 17Aug2018 [019] It has been over 150 years since Jodin first suggested that microbes could fix N2 and more than a century since the first isolation of IXh-fixing bacteria around 1900. In 1934, Burk coined the term nitrogenasefor the enzyme that catalyzes the conversion of N2 to a bioaccessible form of nitrogen, and initiated the first meaningful studies of nitrogenase in living cells. Methods for extracting nitrogenase in an active form were developed in the early 1960s, opening the way for serious mechanistic investigations. The next 35 years witnessed intensive efforts by numerous investigators to reveal the structure and catalytic function of nitrogenase. These developments were summarized in the magisterial review by Burgess and Lowe in 1996. Key advances in understanding nitrogenase structure and function during those intervening years included the following: (i) It was determined that nitrogenase is a two-component system composed of the MoFe protein (also called dinitrogenase or component I) and the electrontransfer Fe protein (also called dinitrogenase reductase or component II). (ii) A reducing source and MgATP are required for catalysis (iii) Fe protein and MoFe protein associate and dissociate in a catalytic cycle involving single electron transfer and MgATP hydrolysis, (iv) It was discovered that the MoFe protein contains two metal clusters: the iron-Molybdenum cofactor (FeMoco), which provides the active site for substrate binding and reduction, and P-cluster, involved in electron transfer from the Fe protein to FeMo-co. (v) Crystallographic structures were solved for both Fe and MoFe proteins, (vi) Also, the alternative V- and Fe-type nitrogenases, in which the Mo of FeMoco is replaced by V or Fe, were discovered. Despite this accumulation of functional and structural information, the catalytic mechanism remained elusive (Hoffman, 2014).

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BRIEF DESCRIPTION OF DRAWING [020] To assist in the understanding ofthe invention, preferred embodiments of the invention will be described by way of example with reference to the accompanying drawings.

[021] FIG 1 shows a holistic sketch ofthe overall process from run of mine natural resource material through to final packaged fertiliser product or metal.

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DETAILED DESCRIPTION OF THE INVENTION [022] Embodiments of the present invention reside primarily in an extraction process which maximises natural resource utilisation by extracting

Molybdenum trioxide from overburden above a metallic mineral deposit.

[023] Metals occur in all kinds of rocks but usually in concentrations that are too low to be mined. Metallic ore deposits, however, are relatively rare concentrations of metal-bearing minerals (usually sulphides) that contain enough metal to be profitably mined.

[024] Stoichiometry is the field of quantitative science involved with chemical reactions. It is an important aspect of the patent. From a chemical engineering perspective, it is all about increasing the concentration of the saleable commodity in any volume of crushed rock to the point where it is 'fit for purpose'. We measure this commonly as percent concentration by volume /volume % or v/v %.

[025] In wet chemistry the numerator in the above fraction is called the solute and the denominator is called the total volume of solution. Similar principles apply to rocks and minerals.

[026] Our naturally occurring ore (molybdite) will have a concentration (grade of Mo) of about 1% by volume.

2018101150 21 Dec 2018 [027] We need to increase this 1% number significantly in order to make our fertiliser products.

[028] Our'base' is molybdite (Molybdenum trioxide) which has a natural and highest stoichiometric concentration of Molybdenum of 66%. Other products such as sodium and ammonium molybdate are derived from the molybdite (Molybdenum trioxide) base. This figure can be derived empirically by simply replacing the elements in the formula with their respective atomic weights and performing the v/v quotient calculation.

[029] In Table 1 below we have done this v/v calculation for the common Molybdenum fertiliser products. Some numbers are higher (richer products) than others and each product has its own role in agriculture. For example, Molybdite is sometimes preferred for soil conditioning as opposed to sodium molybdate (a type of salt) which may be used as foliate.

TABLE 1

Types of Molybdenum Oxides

Source	Formula	% Molybdenum
Ammonium Molybdate	(NH₄)e M07O24.2H2O	54
Molybdenum Trioxide	MOO3	66
Sodium Molybdate	Na₂MoO₄.2H₂0	39

2018101150 21 Dec 2018 [030] Our market differentiators revolve around how we plan to make our products as well as the uniqueness of the products themselves.

[031] The simplest way to increase our grade of Molybdenum Trioxide in our products is to make use ofthe naturally high density ofthe metal (and even in the oxide form). Gravity separation techniques are the obvious solution. This is a mechanical technique involving no addition of chemicals. This technique has been used in the mineral sands industry for decades.

[032] In terms of invention one of our unique outputs will be our initial product mix using our base molybdite compound. We plan to mix it with compost to make an organic fertiliser.

[033] It is also only within the shallow weathered zone that the molybdite fertiliser occurs, thus creating a unique marketing opportunity for KM in the future to take its molybdite fertiliser manufacturing method and apply it to what are currently millions of tons of useless overburden at various Mo deposits both within Australia and around the world.

[034] According to United States Geological Survey (USGS) data, updated by Geoscience Australia for Australia's resources, world economic resources of Molybdenum in 2011 were estimated to be about 10 100 kt with China holding 43% of the resources followed by the USA with 27% and Chile with 12%. Australia accounts for just over 1.5% ofthe world's economic resources of Molybdenum metal.

2018101150 21 Dec 2018 [035] Molybdenum metal worldwide is only produced as a by-product of copper production. There are no Molybdenum Oxide specific mines anywhere in the world. Thus, the only current producers of molybdite for fertiliser are also producing copper - Molybdenum mines. In other words, there are no mines anywhere in the world that are dedicated to molybdite fertiliser production. Chemical engineers struggle to liberate anything economically from the upper parts of these deposits.

[036] Kynoch Minerals Pty Ltd (KM) plans to be the world's first and only producer for dedicated molybdite production from natural ore.

[037] In terms of molybdite fertiliser Climax Molybdenum Co. (Climax) is the world's leading producer of Molybdenum chemical products such as molybdite. Jinduicheng Molybdenum Co Ltd (China) (Jinduicheng) as well as being Asia's largest Molybdenum Trioxide producer is also a major producer of molybdite fertiliser chemicals. These two producers would be our international competitors for molybdite fertiliser production.

[038] Strategically KM would however become the only molybdite producer in the Southern Hemisphere and could preclude Australian farmers and fertiliser manufacturers having to import this product.

2018101150 21 Dec 2018 [039] From an 'organic clean and green' perspective because our molybdite does not come out of a metal refinery as do the chemicals at Climax and

Jinduicheng, it may well find a unique market, even in places like China and

India which increasingly look to Australia as part of their food security strategy.

[040] KM's molybdite will be produced by physical extraction methods which are compliant to organic farming standards both in domestic and international markets.

[041] The final products are either a white powder or crystalline substance.

[042] You cannot use superphosphate or urea for all fertiliser needs. These are inorganic fertilisers and the trend worldwide now is for organic and naturally sourced fertilisers.

[043] The fertiliser market is as large as legume production itself which is very large worldwide, particularly in the Asian economies such as India and China.

[044] While the quantity of molybdite for use on individual farms measured in kg per hectare is small (e.g. 2kg/ha), the hectares of land under cultivation for legumes is enormous and growing rapidly.

2018101150 21 Dec 2018 [045] India has the largest share of pulse production in the world at 25%. A quarter of the country is used for pulse production to feed the country's people. Among the pulses, chickpea contributed 48%, Pigeonpea 17%, blackgram 10%, greengram 7% and other pulses 18% towards total pulses production.

[046] Pulses are important source of protein, high in fibre content and provide ample quantity of vitamins and minerals. Keeping in view large benefits of pulses for human health, the United Nations proclaimed in 2016 as the International Year of Pulses. Thus, due attention is required to enhance the production of pulses not only to meet the dietary requirement of protein but also to raise the awareness about pulses for achieving nutritional, food security and environmental sustainability.

[047] Pulses crops don't just feed people, they are good for the soil fertility.

[048] In India, the acreage for pulses ranged from 20.35 (2000-01) to 23.99 million ha (2012-13) and production varied from 11.08 (2000-01) to 18.45 million tons (2012-13). The productivity has increased from 544kg/ha (2000-01) to 750 kg/ha (2012-13). The major pulses producing states are Madhya Pradesh (25%), Utter Pradesh (13%), Maharashtra (12%), Rajasthan (11%), Andhra Pradesh (9%) and other states together (30%) during 2012-13.

(Mujumdar, 2011)

2018101150 17Aug2018 [049] Some simple math highlights the potential for a 'legume booster' market. If we assume just one annual application of molybdite for each hectare of farm under legume production:

million hectares (ha) * 1 kg/ha * $40 I kg Equation 02 = $ 0.1 Billion (USD) [050] This is just one annual treatment for one county.

[051] The Asian market alone could be worth many billions of dollars for molybdite fertiliser.

[052] The following discussion related to the drawings.

[053] The elements of the apparatus have been illustrated in concise schematic form in the drawings, showing only those specific details that are necessary for understanding the embodiments of the present invention, but so as not to obscure the disclosure with excessive detail that will be readily apparent to those of ordinary skill in the art having the benefit of the present description.

2018101150 17Aug2018 [054] In this specification, adjectives such as first and second, left and right, and the like may be used solely to distinguish one element or action from another element or action without necessarily requiring or implying any actual such relationship or order. Words such as comprises or includes are intended to define a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed, including elements that are inherent to such a process, method, article, or apparatus.

[055] Referring to FIG 1 there is shown a holistic sketch of the mining steps (1-7) and processing steps (8-27) which detail this application.

[056] Steps 1 to 7 are common to any mining operation. What is mining? Mining may be defined as the act, process or work of extracting earth materials from where they occur and then transporting them for processing or immediate use. A mine is therefore an excavation in the earth.

[057] Most of the remaining steps in FIG 1 relate to mineral processing. The goals of mineral processing are to a) separate mineral particles from waste or gangue (rock minerals) b) subject minerals to processes in order to concentrate them or to extract metals from them. Mineral Processing comprises two steps; comminution and classification.

2018101150 21 Dec 2018 [058] Comminution is the process of breaking rock material into smaller pieces. The aim of comminution is to liberate mineral grains in preparation for separation. It is common to consider comminution to be divisible into two subsets; crushing and grinding. The distinction is made on the basis of mechanical criteria, i.e. the machine types that are used to accomplish the rock breakage.

[059] The crushing stages and the typical size ranges associated with the stages are threefold; primary - mined blocks are reduced to 8-15 cm diameter, secondary - 1cm to 0.5 cm output, tertiary - 0.5 cm output or less.

[060] Classification is the term given to separation of mineral particles based on particle size. Classification behaviour is influenced by the size, shape and density of the individual particles. Two common types of classifiers are screens and hydrocyclones (spirals). With screens, separation takes place by letting fine particles fall through openings in the screen deck. With cyclones, large particles settle faster than small particles of the same mineral. Dense particles settle faster than light particles of the same size and shape and this allows us to separate individual particles. Centrifugal force speeds up the settling. A cyclone uses a rotational motion to create the centrifugal force.

2018101150 21 Dec 2018 [061] Step 1 represents Run of Mine (ROM) ore which is produced by long standing mining industry processes of scraping (if the ground is soft enough) or drilling and blasting. Step 2 represents primary crushing which is designed to make small rocks from large rocks delivered by the previous drill and blast process. Crushed rocks are typically screened in Step 3 to filter off the smaller material which is conveyed in Step 4 to a coarse ore stockpile (Step 5) from where it is conveyed in Step 6 to a secondary crusher (Step 7) where the rock is crushed to even smaller particle size.

[062] Again, the products from the crushing are screened (Step 8) in order to filter the finer material in preparation for gravity separation by cyclones in Step 9. Spirals have been used in Mining Engineering for many decades to gravity separate commodities such as mineral sands in order to exploit the relative density contrast of commercial commodity (e.g. Titanium rich spinel) from barren gangue minerals such as sand. By the completion of Step 7 our ROM will be of silt size or smaller.

[063] A screen in Step 8 will filter off the valuable material coming out of the Cyclone Gravity circuit (Step 7). Oversize material (Step 10) can be recycled through the gravity circuit as (Step 11) as required. The material emanating from the spirals is piped in Step 12 to a Molybdenum Oxide stockpile (Step 13). At this stage the source material for fertiliser or other molybdenum products has been created.

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BIBLIOGRAPHY (Non Patent Literature)

Amax Inc . (1975). Patent: Direct reduction of molybdenum oxide tosubstantially metallic molybdenum. N/A. Retrieved from https://patents.google.com/patent/US4045216

Hoffman, B. (2014). Mechanism of Nitrogen Fixation by Nitrogenase: The

Next Stage. Chemical Reviews, 114(8), 4041-4062. Retrieved from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4012840/

Leigh, G. (2004). Haber-Bosch and Other Industrial Processes. In: Smith

B.E., Richards R.L., Newton W.E. (eds) Catalysts for Nitrogen Fixation. Nitrogen Fixation: Origins, Applications, and Research Progress, vol 1. Dordrecht: Springer

Mujumdar, D.K. (2011). Pulse Crop Production - Principles and Technologies. PHI Learning Private Limited, New Delhi.

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Claims

1. A process which maximises resource utilisation by extracting valuable molybdenum trioxide from overburden developed by oxidation processes above a metal deposit.