The world has produced about 800 million tons of aluminium since the modern aluminium industry began in 1886 – and about 73 percent is still in use today. But the aluminium industry is still growing, and FLSmidth offers a large range of services to assist aluminium producers increase production.
Aluminium represents about eight percent of the earth’s crust (only oxygen and silicium are more common), but it wasn’t until 1886, when Hall-Heroult invented an electrolytic reduction process to produce primary aluminium from alumina, that the world started producing, and using, aluminium on a large scale. Today, aluminium is an important metal for the mining industry. Six of the fifteen largest mining and metal companies produce primary aluminium, and worldwide production totals around 37 million tpy.
Urbanisation and a growing industry
The aluminium industry is growing, thanks to the properties and the versatility of the metal. Aluminium has a huge array of uses and is found in thousands of products around the world. And as urban populations grow, so does the demand for aluminium.
Currently, the BRIC countries (Brazil, Russia, India and China) have a low per capita consumption of aluminium (1-8.5 kilograms compared to 20-25 kg in Europe and the US). But this consumption is expected to increase – and so is the demand for alumina refineries. India in particular is an attractive country for investors, as it offers large reserves of good quality bauxite combined with relatively low investment and operating costs.
Reducing environmental impact
It takes about 285 gigajoules of energy to produce one ton of primary aluminium, but only 15 gigajoules of energy to produce one ton of secondary aluminium from recycled products, such as aluminium cans and scrapped vehicles. And today, about 73 percent of all the aluminium produced since 1886 is still in use.
Aluminium is a relatively environmentally friendly material. Utilising aluminium instead of traditional materials, such as steel – results in lower CO2 emissions. The use of aluminium in transport industries, particularly the automotive industry, is estimated to have reduced CO2 emissions by around 250 million tpy.
FLSmidth’s synergies with the cement industry
FLSmidth first entered the alumina industry more than 100 years ago, offering tube mills for grinding bauxite and long rotary kilns for the calcination of aluminium hydroxide or hydrate to alumina. But it was the 1973 oil crisis that forced alumina producers to look for new ways to reduce energy consumption.
Stationary calciners became the industry standard almost overnight thanks to their ability to reduce fossil fuel consumption by 25-30 percent compared to rotary kilns. The new precalcination technology developed by FLSmidth for cement led to the Gas Suspension Calciner for alumina, which saw the light of day for the first time in 1984, when it was ordered by Hindalco in India.
The Gas Suspension Calciner – a new industry standard
At just 850 tpd, this first Gas Suspension Calciner (GSC) was small by today’s standards, but it was a huge leap forward for FLSmidth and became a huge success. Soon GSCs were installed in plants around the world, particularly in China and the US. In 1989, FLSmidth delivered the next two alumina GSCs, which together with four 51 m2 horizontal pan filters supplied by Dorr-Oliver (now part of FLSmidth) were capable of churning out 1850 tpd. The installation at the Sherwin Alumina Plant (formerly Reynolds) in the US was the first aluminium hydroxide filtration and washing unit with combined alumina calcination supplied by FLSmidth.
To further drive process optimisation and capacities, FLSmidth teamed up with Alcoa Inc. in 2001. At the time, Alcoa was the world’s largest producer of aluminium, and the technological alliance was designed to push innovation even further. The project united FLSmidth’s engineering expertise with Alcoa’s practical operating experience, and the first results of the alliance were the GSCs installed in the Queensland Alumina (QAL) plant in Australia. Each of the three GSC units is capable of producing 4500 tpd – and they are the largest calciner units in the world today.
The GSC units in QAL represent a complete rethink of traditional GSC process design – using a partly pressurised system instead of a complete negative pressurised system. And to ensure they meet new particulate emission standards for alumina refineries in Australia, the units also include FLSmidth bag-houses.
The full-package of the future
FLSmidth acquired Dorr-Oliver Eimco and Krebs in 2007, bringing solid-liquid separation technology into the FLSmidth fold – and opening a whole new chapter for FLSmidth in the alumina industry.
FLSmidth now offers a ‘Calcination Package’ with integrated filtration and calcination technology – and the Anrak Alumina Refinery in India is the latest refinery to receive it. The package includes equipment and technology for hydrate filtration, gas suspension calcination with bag-house, and alumina handling and load-out. As well as receiving the latest technology, Anrak also benefits from working with a supplier that offers the entire package: all the main equipment is manufactured and/or designed by FLSmidth and the project is supported by a strong international team of engineers.
FLSmidth has an experienced team of engineers and support staff with extensive alumina experience located in offices around the world – and offers the latest equipment for most areas of an alumina plant.
How is aluminium produced?
Aluminium production begins with bauxite, a clay-like ore with a high aluminium oxide content. Bauxite is put through a refining process in which alumina is produced through a calcination process. This alumina then feeds a smelter process to produce primary aluminium. Secondary aluminium is produced from recycled aluminium.
Red side, white side and alumina handling
Based on the Bayer process, invented by the Austrian chemist Josef Bayer, the alumina production process can be split into a ‘red side’ and a ‘white side’.
Red side solutions
FLSmidth now offers equipment for the complete bauxite handling, storage, crushing and grinding flow sheet, complementing the digestion or dissolution of bauxite in hot caustic liquor. This is followed by the complete Settler-Washer train flow sheet for Red Mud using the leading technology acquired from Dorr-Oliver Eimco (see here).
White side solutions
FLSmidth offers white side equipment, covering the complete flow sheet after the hydrate precipitation process, including equipment technology from FLSmidth Moeller for alumina handling and load-out.
Overall, FLSmidth equipment covers more than 50 percent of the equipment needs of a complete alumina plant, from the bauxite mine to the above refinery equipment. ?In addition, FLSmidth also offers all equipment for alumina handling in the smelters.