High purity alumina juniors eye development opportunities

By Antonio Torrisi
Published: Monday, 22 September 2014

AMMG outlines commercialisation plan, as Orbite Aluminae completes phase 1 of its HPA plant construction and Leigh Creek Magnesite moves forward.

Australian exploration company, Australian Minerals Mining Group (AMMG), has announced a strategy to become a low-cost, high-purity alumina (HPA) producer.

Following a technical review of previous testwork, the company has proposed a process flow design and integrated plant study to confirm the technical viability of producing HPA from its aluminous clay resources near Meckering, Western Australia (WA).

According to AMMG, the production of 99.99% HPA directly from its kaolin resources is a low-cost alternative compared with
traditional production from aluminium metal, which has to be expensively and highly processed from bauxite ore.

“We have a robust and proven processing technology with enormous potential for producing HPA. We are in the right place at the right time with the right feedstock and the right technology,” Iggy Tan, AMMG’s managing director, said in a statement.

The company, which is also exploring for mineral sands, graphite and gypsum resources in WA, aims to move away from mineral exploration and focus on HPA production, Tan said.

A study published by AMMG in June showed that its planned HPA pilot plant had a capex of under Australian dollar (A$) 10m ($9.1m*), and that capex and opex estimations for an integrated plant were significantly lower than previous figures estimated in December 2013.

The HPA process

The production route planned by the company consists of using hydrochloric acid (HCl) leaching with gas induced crystallisation and acid recovery, which will be reused at the front end of the process, therefore reducing operating costs.

AMMG said that the HCl leaching process, which has been known since the early 1980s, is particularly effective for its aluminous clay deposits, due to their low impurity content.

Low levels of impurities

The company explained that as its kaolin resources have been purified and processed by natural weathering processes, it contains very low levels of impurities such as iron, titanium, calcium, potassium and magnesium, compared with raw bauxite ore.

“The main impurity [of the aluminous clays] is insoluble silica which can be easily filtered out during the processing, leaving the soluble alumina,” AMMG said in a press release.

“By contrast, bauxite ore used to produce aluminium metal and alumina contains around 22% iron compared to the aluminous clay feedstock at Meckering, which contains 0.7% iron impurities,” it added.

AMMG and Canada-based Orbite Aluminae are the only two companies in the world which are developing a process to produce alumina from aluminium clays. A comparison of their chemical compositions is detailed below (Table 1).

A growing market for HPA

The Australian junior said it expects HPA demand will grow in the near future, especially in synthetic sapphire glass production for LEDs and other high-tech sectors, including smart phones, semiconductors, plasma screens, lithium batteries and optical devices.

According to a report published by Technavio Research in April, the global HPA market will grow its capacity at a compound annual growth rate (CAGR) of 27.88% over the period 2013-2018, with present volumes of 19,040 tonnes expected to expand to 48,200 tonnes by 2018.

Prices increasing with purity

AMMG said that price of HPA is expected to increase with its purity, as the alumina (Al2O3) content in the product needs to be very high in order to satisfy requirements from the electronic and technology industry.

Prices for HPA with a grade of 99.9% Al2O3 are presently between $1-10/kg, with prices for HPA grades of 99.99% and 99.999% Al2O3 being up to $10-50/kg and $50-150/kg, respectively, according to the company.

Orbite Aluminae completes first phase of HPA construction

Canada’s Orbite Aluminae has completed the first phase of construction of its HPA plant at Cap-Chat in Quebec, Canada.

The company has concluded the structural reinforcement of the HPA building and has installed the calcination equipment that was provided by Finland-based processing company, Outotec.

“Overall work on the HPA facility continues on schedule for commercial production in Q1 2015,” Denis Arguin, Orbite’s vice president of engineering and operations added, stating that the refractory installation contract is presently under negotiation.

Low cost alumina production

With the first phase of the construction plan concluded, Orbite has completed the basic engineering for a proposed smelter-grade alumina production plant, which will use the clay mined from its Grande-Vallee deposit in Quebec, Canada, as feedstock.

The company aims to produce metallurgical grade alumina, high purity alumina and rare earths from clay, red mud, bauxite and fly ash, through an innovative process which is protected by 16 patents.

The process involves crushing and acid leaching of the aluminous claystone, followed by the isolation of aluminium components at different temperature and pH levels, and the removal of iron and other impurities, including rare earth metals.

*Conversion made September 2014

Archer Exploration settles magnesite dispute

Wayville, Australia-based Archer Exploration Ltd, has settled a dispute over its Leigh Creek magnesite deposit in South Australia, which will allow the company to immediately start exploration at the site.

Archer said it has entered into a confidential settlement agreement with Sydney, Australia-headquartered junior Foyson Resources Ltd, which will stop proceedings started by Foyson in July.

In December 2013, Foyson’s subsidiary, Magnesium Developments Ltd (MDL), launched proceedings in the South Australian Warden’s Court against Archer’s subsidiary Leigh Creek Magnesite Pty Ltd.

MDL claimed mineral and extractive leases over part of the Leigh Creek Magnesite project, which allowed it to mine all magnesite within the area, according to the Australian Mining Act.

Archer, which claimed entire ownership of the project, announced the discontinuation of the Warden’s Court action in July this year.

“The plaint dealt with complex issues under the Mining Act and could have resulted in a detrimental impact on the Mount Hutton magnesite project, had it succeeded,” Archer said in a statement.

Following the discontinuation, Foyson commenced an additional action in the Supreme Court for an amount of A$250,000, claiming that Archer made a binding offer to settle the Wardour’s Court dispute.

While defending against any claims brought in by Foyson, Archer started negotiations with the Sydney-based company to resolve the dispute.

Leigh Creek magnesite

Leigh Creek holds a JORC compliant resource of 453m tonnes, grading at 41.4% magnesia (MgO).

“Archer has conducted significant calcining testwork to show that the magnesite [ore] can produce high-quality MgO, suitable for a multitude of uses, including in hydrometallurgical extraction of metals, agricultural applications including fertilisers, water purification and wall board production,” Anderson said.

MgO is also used as clinker in refractory applications.

The company appointed consulting firm EY in July to conduct a strategic review of the asset, which Archer expects to complete by the end of this year.

“Our approach is to acquire prospective or unrecognised projects, which we then add value to through firming up resources and putting together project plans,” Gerard Anderson, managing director, said.

“Once we have completed this work we will seek to monetise those assets either through divestments, joint ventures or bringing the projects to production,” he added.

Archer is also developing its Campoona fine graphite project in the Eyre Peninsula, South Australia.