Tag Archives: SMI

Vale’s Sustainable Sand wins plaudits as miner starts construction on ‘green pig iron’ plant

Vale’s sustainability efforts are continuing to be displayed to the rest of the industry, with the major miner making a significant contribution to a report on the sustainable use of sand in mining and starting construction on a ‘green pig iron’ production facility in Brazil.

On the former, the University of Queensland, through its Sustainable Minerals Institute (SMI), and the University of Geneva, recently released a report indicating that sand from the ore production process may contribute to solving two important environmental issues by reducing sand extracted from the natural environment and the mining tailings generation. Vale contributed to the report and facilitated the sampling of its Sustainable Sand produced at the Brucutu mine in Minas Gerais for an independent analysis.

Vale’s Sustainable Sand is a co-product of iron ore processing. Based on adjustments in the operation, the sandy material, previously disposed in piles and dams, is now processed and transformed into a product, following the same quality controls as in the iron ore production. This year, Vale will allocate around 1 Mt of sand, between sales and donations, for use in civil construction and tests in pavement, among other uses.

The company came up with the process after seven years of research and investment of about BRL50 million ($8.9 million), it said last year.

The SMI report carried out by the universities, ‘Ore-sand: A potential new solution to the mining tailings and global sand sustainability crises’, investigated whether sand from ore processing, described by the term “ore-sand”, could become a sustainable source of sand and at the same time reduce the volume of tailings generated by mining.

Material characterisation results from the report indicate that the sampled material is inert and non-toxic, and can be suitable for certain applications, either on its own or as a part of a blend, such as with coarser sand, in order to meet specific grading requirements. Separating and repurposing these sand-like materials before they are added to the waste stream would not only significantly reduce the volume of waste being generated but could also create a responsible source of sand, Vale said.

The report found that, from a technical perspective, sand from iron ore operations can be a direct substitute for sand extracted from the environment in brick making, pavement, in embankments and cement manufacturing. When mixed with coarser sand and other aggregates, it can be used in the production of concrete and mortar, drainage and soil improvement, and water treatment.

The life cycle assessment of “ore-sand”, based on the case of Vale’s Sustainable Sand, also shows that this material has the potential to present lower net carbon emissions during its production when compared with sand extracted from the environment. However, to get a better idea of the potential of this reduction, it is necessary to carry out an assessment of the product’s transport stage, which was not covered in this report, Vale added.

Last week, Vale inaugurated the first road in Brazil using “ore-sand” in all four layers of the pavement. The 425-m-long road at the Cauê mine, in Itabira, will be monitored for two years with pressure, temperature, deformation and humidity sensors. Tests carried out during five years in the laboratory showed an increase in lifespan of around 50% and a cost reduction of 20% when compared with the most commonly used materials for road construction, such as sand extracted from the environment, Vale said. In addition, each kilometre of pavement can consume up to 7,000 t of tailings.

‘Green pig iron’

Earlier in the month, Vale and the Government of the State of Pará held an event to mark the beginning of the construction works of the first commercial plant of Tecnored in Brazil. Tecnored’s technology allows the production of so-called ‘green pig iron’, by replacing metallurgical coal with biomass, thus reducing carbon emissions and contributing to the decarbonisation of the steel industry.

The unit will have an initial capacity to produce 250,000 t/y of green pig iron, with the possibility of reaching 500,000 t/y in the future. The start-up is scheduled for 2025 with an estimated investment of approximately BRL1.6 billion ($342 million).

Vale’s President, Eduardo Bartolomeo, said the implementation of Tecnored represents an important step in the transformation of mining, contributing to making the process chain increasingly sustainable.

“The Tecnored project is of great importance to Vale and to the region and will bring gains in competitiveness, environmental sustainability and development for the region,” he said.

Eduardo Bartolomeo greets the Governor of Pará, Hélder Barbalho, during the launch ceremony for the Tecnored commercial plant

In the implementation phase of the project, which will work in the area of the old Ferro-Gusa Carajás, in the industrial district of the municipality, it is estimated that around 2,000 jobs will be generated at the peak of works. In the operational phase, about 400 direct and indirect jobs should be created, according to progress and engineering studies.

The Tecnored furnace is much smaller in size than a traditional steel blast furnace and is flexible in its use of raw materials, which can range from iron ore fines and steel residues to dam sludge, Vale said.

As fuel, the furnace can be fed by carbonised biomass, such as sugarcane bagasse and eucalyptus. Both are transformed into briquettes (small compact blocks) and deposited in the furnace, generating green pig iron. The furnace also allows the use of thermal coal itself as fuel. In this first instance, fossil fuels will be used to evaluate the performance of the plant, Vale explained.

Leonardo Caputo, Tecnored’s CEO, said: “Gradually, we are going to replace coal with carbonised biomass until we reach the goal of 100% biomass.”

The flexibility in the use of fuels in the furnace allows operating costs to be reduced by up to 15% compared with a traditional blast furnace, Vale claims.

Developed over the last 35 years, Tecnored’s technology also eliminates the coke furnaces and sintering processes: stages prior to the production of steel in the steel mill that are intensive in their greenhouse gas (GHG) emissions. This also reduces capital costs by up to 15%, according to Vale.

In addition, the plant is self-sustaining in terms of energy efficiency, with all the process gas reused and a portion used for energy co-generation, the company said. The slag by-product can be used as raw material in the cement industry.

Currently, Vale maintains a demonstration plant of this technology in Pindamonhangaba, with a rated capacity of 75,000 t/y, where tests were carried out to develop the technology and technical and economic feasibility.

Tecnored’s commercial plant in Marabá is part of Vale’s effort to offer its steelmaking customers technological solutions to help decarbonise their production processes.

In 2020, the company assumed the goal of reducing Scope 3 net emissions by 15% by 2035. Of this total, the company will contribute up to 25% through a high-quality products portfolio and technological solutions, including green pig iron. Today, the steel industry represents 94% of Vale’s Scope 3 emissions.

Vale also announced the goal achieving net zero Scope 1 and 2 emissions by 2050 and, to that end, it is investing between $4-6 billion, as well as committing to recover and protect another 500,000 ha of forest in Brazil.

SMI-ICE-Chile projects taking on BHP Tailings Challenge

Two proposals supported by the Sustainable Minerals Institute’s International Centre of Excellence in Chile (SMI-ICE-Chile) are advancing to the second round of the BHP Tailings Challenge.

A global competition that aims to fundamentally change how the industry manages copper tailings, the BHP Tailings Challenge announced in January that 10 companies and consortia had been selected to advance to the laboratory test stage of the program. The challenge is seeking solutions and new business models to reuse copper tailings.

The SMI-ICE-Chile-supported proposals advancing to the proof-of-concept stage include one from the Solar Tailings Transformation (STT) Consortium, which SMI-ICE-Chile leads. This consortium is proposing a solution that integrates several solar thermal energy-powered processes to convert tailings material into a stable multi-purpose pellet and high-quality water.

SMI-ICE-Chile is also the local coordinator of the Recomine proposal, which is led by the Helmholtz-Institute Freiberg for Resource Technology and is focused on the development and integration of a series of modular processes to separate out valuable products from the tailings.

The BHP Tailings Challenge, supported by Fundación Chile through its Expande program, aims to promote and deliver new technological solutions and business models for reusing copper tailings, and will provide $10 million in grants to successful developers.

The teams advancing to the proof-of-concept stage are given a $50,000 grant and sample of tailings with which to validate their solutions at a laboratory level before demonstrating its technical and economic feasibility in a demo day in August 2021.

SMI-ICE-Chile Sustainability Leader, Dr Douglas Aitken, said both proposals are innovative solutions that have the potential to drive positive change in tailings management practices and generate considerable value to industry and society.

“The social and environmental issues associated with tailings represent a major challenge for the industry, but by replacing the traditional disposal-based approach with new and innovative value recovery solutions, we aim to eliminate the negative aspects of tailings and instead create social and economic benefits,” he said.

The BHP Tailings Challenge provides an opportunity to develop and test exciting new ideas that could result in the tailings management process becoming safer and an industry asset instead of a burden, SMI-ICE-Chile added.

Dr Felipe Saavedra, the STT project lead for the SMI-ICE-Chile team, explained the proposed concept and the expected benefits.

“The STT consortium is a multi-disciplinary group comprised of researchers from SMI-ICE-Chile, SMI, IMDEA Energy, SEENSO, and Aiguasol Latam,” he said. “The proposed concept aims to repurpose over 50% of operational tailings production using solar thermal energy to dewater the tailings and produce a stable and flexible end-product.

“It is a sustainable approach that takes a complex and difficult-to-handle mine waste and transforms it into a material that can be used by numerous local industries, such as construction, road building and agriculture. We expect that the recovered water will also have considerable value for local water users, its availability should offset freshwater extraction from natural resources, thereby protecting local ecosystems.”

Dr Saavedra concluded: “We hope that the solution will generate wide-spread social and economic development and we’re looking forward to testing the technologies with our partners in the coming months.”