Volume 92 Issue 8 | pp. 33-35
Issue Date: February 24, 2014

Making The Most Of Red Mud

An octogenarian chemist’s latest invention turns hazardous aluminum mining waste into a material for cleaning up water
Department: Science & Technology | Collection: Safety, Entrepreneurs, Sustainability
News Channels: Materials SCENE, Environmental SCENE
Iannicelli poses with a sample of his sulfidized red mud sorbent, called Azorb.
Credit: Aquafine
This is a photo of Joseph Iannicelli, president of Aquapure Corp.
Iannicelli poses with a sample of his sulfidized red mud sorbent, called Azorb.
Credit: Aquafine

Joseph Iannicelli is an inventor unlike any other you might have met. He is the 84-year-old president of Aquafine Corp., a Brunswick, Ga., company that supplies spray-drying and magnetic separation equipment and provides laboratory services for industrial mineral processing. Iannicelli holds dozens of patents for technologies used to purify kaolin, a white aluminum silicate mineral that is essential to making paper, cosmetics, paint, and sorbents for water treatment.

Iannicelli has amassed a small fortune since he graduated from Massachusetts Institute of Technology with a Ph.D. in organic chemistry back in 1955, when he helped develop a biosynthetic method to make penicillin. After working for DuPont on textile fiber polymers and for J. M. Huber Corp. on kaolin, he launched Aquafine in 1971.

In conversations, Iannicelli spontaneously recalls the details of his diverse inventions. His firm baritone leaves the listener hanging on his every word as he weaves a tale to explain how he lately came to be interested in playing with red mud.

Known formally as bauxite residue, red mud is the noxious by-product of the Bayer process for extracting aluminum from bauxite ore. Aluminum mining leaves behind a staggering 120 million metric tons per year of the salty, highly alkaline, heavy-metal-laden material, according to the International Aluminium Institute, a London-based trade organization. The aluminum industry has long tried to find ways to recycle the environmentally problematic red mud. But so far there have been few safe and economical large-scale applications.

“Red mud is a curse,” Iannicelli observes. “There is no shortage of simple, ingenious solutions for dealing with most categories of environmental pollution, including red mud. The deciding factors on implementation are cost and safety.”

The red hue of bauxite stands out at the Paragominas mine in Brazil.
Credit: International Aluminium Institute
This is a photo of a paragominas bauxite mine, in Brazil.
The red hue of bauxite stands out at the Paragominas mine in Brazil.
Credit: International Aluminium Institute

Iannicelli’s solution for red mud is to treat the abundant material with cheap sulfur compounds. Doing so locks in trace metals and improves the material’s sorbent properties, he says, so it can be used for cost-effective wastewater treatment and in other environmental remediation applications. He calls the sulfidized red mud Azorb.

In the Bayer process, strip-mined bauxite is treated with hot caustic soda (sodium hydroxide), which selectively dissolves aluminum from an array of other mineralized metals. The end product is alumina, Al2O3, which is the feedstock for producing aluminum metal.

But for every ton of alumina extracted, more than a ton of red mud is produced. Bauxite processors recycle the caustic soda and pump the residual red sludge into huge settling ponds. When as much water is removed as possible, the material can be chemically treated to lower the pH and planted over with vegetation.

The scourge of red mud burst into the public’s eye in October 2010 when a settling pond in Hungary ruptured. A flash flood of red sludge gushed through several small towns, killing 10 people by drowning and injuring more than 100 others by burning their skin and irritating their eyes and lungs.

Iannicelli isn’t the first person to think about getting his hands dirty with red mud to help prevent such disasters. Australia-based industrial waste management firm Virotec has developed a process to neutralize red mud with copious amounts of seawater or brine. The resulting material is generally used to remediate mining sites, but it is also used as filler to make bricks and as a sorbent to trap metals and phosphorus in wastewater.

Aluminum producer Alcoa has a process to carbonate red mud using CO2 from industrial gas streams. The resulting “red sand” is used to make cement and in road construction. Others have developed processes to recover iron and rare-earth metals from red mud. But so far, only 2 million metric tons of red mud is being repurposed annually—less than 2% of the amount being generated.

Once aluminum is extracted from bauxite, the remains are a porous matrix of metals—a mineral skeleton, Iannicelli explains. As much as half of red mud is iron oxide, from which it gets its rusty color. Other major components include aluminum, silicon, titanium, calcium, and sodium oxides. The material includes trace amounts of other metals, including radioactive uranium.

As a rule of thumb, 4 metric tons of bauxite yields 2 tons each of alumina and red mud, and in turn 1 ton of aluminum metal. SOURCE: International Aluminium Institute
Credit: International Aluminium Institute
alumimium metric tons
As a rule of thumb, 4 metric tons of bauxite yields 2 tons each of alumina and red mud, and in turn 1 ton of aluminum metal. SOURCE: International Aluminium Institute
Credit: International Aluminium Institute

With a high surface area, red mud is a natural sorbent capable of grabbing heavy metals and organic contaminants and sequestering them. But red mud can also leach toxic heavy metals, which is an environmental concern.

Iannicelli’s sulfidation process involves treating red mud with sulfur compounds under ambient conditions or with mild heating. Any of a number of sulfur compounds will do the job, he says, including Na2S, (NH4)2S, and H2S. In the sulfidation reaction, sulfur atoms bind to vacant spots on metals throughout the skeletal network, locking the metals into place and preventing them from leaching.

Sulfidation also tunes the red mud so that it has significantly higher sorbent capacity than untreated red mud, Iannicelli says. He has been testing Azorb’s sorbent capabilities in side-by-side tests with untreated red mud using solutions of different metal salts.

Azorb removes better than 90% of most metals from aqueous solutions, Iannicelli says. His team has achieved better than 99% removal rates for metals of concern such as cadmium, chromium, lead, and mercury. The sulfidized red mud is not as efficient at removing arsenic, manganese, and strontium as red mud itself, Iannicelli says. But he suggests mixtures of red mud and sulfidized red mud might be an option for some applications. Once used, the material would be placed in a landfill.

“This work is certainly a very interesting study to detail the removal of a wide range of different species,” says Justin Hargreaves, a chemist at the University of Glasgow, in Scotland. “Particularly interesting is that consideration has been given to the possibility of the red mud systems being sources of contaminants themselves and the application of sulfided and nonsulfided red mud combinations to optimize removal efficacies.”

Hargreaves and his colleagues have been treating red mud with methane, a readily available by-product of oil refining and landfills. Red mud catalytically decomposes methane to form hydrogen and an iron-carbon composite. The Glasgow researchers think the inexpensive magnetic composite material could be used to remove impurities such as arsenic and chromate from drinking water in developing countries.

Iannicelli has also tested Azorb to clean up water discolored with natural dissolved organic compounds, such as tannins and lignin. This is a problem encountered when the effluent of pulp and paper mills is discharged into rivers. Although such water isn’t always considered polluted, when water clarity is unnaturally impacted the effluent is in violation of the intent of clean water laws.

This aerial view of the Mineração Rio do Norte bauxite mine in Brazil reveals the extent of red mud settling ponds—more than a mile long—at an aluminum mining operation.
Credit: International Aluminium Institute
This is a photo of Mineração Rio do Norte bauxite mine, in Brazil.
This aerial view of the Mineração Rio do Norte bauxite mine in Brazil reveals the extent of red mud settling ponds—more than a mile long—at an aluminum mining operation.
Credit: International Aluminium Institute

With that in mind, Iannicelli has shown that Azorb readily traps and removes discolored compounds from Okefenokee Swamp water. Iannicelli also has been working with Altamaha Riverkeeper, a nonprofit environmental stewardship organization that is concerned with discolored water in the Altamaha River, which drains central Georgia. The discolored water there mostly comes from a Rayonier wood pulp mill that manufactures cellulose fibers used in plastics and as an absorbent material in products such as diapers. In preliminary tests on the river water, Azorb removed the discolored compounds, Iannicelli says.

Iannicelli also owns a colonial-era rice plantation in Georgia. The plantation is no longer farmed, but it is home to a mobile home park that has its own wastewater treatment facility. As a licensed wastewater engineer, Iannicelli has carried out water treatment tests using Azorb. His team found that Azorb removes phosphorus and fecal coliform bacteria, the major contaminants of concern in wastewater, to below detection levels.

Not content to stop there, Iannicelli had technicians with the Jekyll Island State Park Authority in Georgia test Azorb on municipal wastewater. They obtained similar results, providing an independent confirmation of phosphorus and bacteria removal.

Iannicelli has also talked with scientists at a large coal-fired power plant about the prospects of using Azorb to remove mercury and selenium, the two metals of greatest concern in scrubber gas wastewater.

“There is a long history of attempts to reformat red mud for beneficial use, with none to my knowledge having proved successful on a large scale,” says Ian T. Burke, an environmental scientist at the University of Leeds, in England. Burke remains skeptical that the abundant red mud can safely be used.

Last year, Burke led a team that took a look at three of the most hazardous trace metals in the Hungarian red mud: arsenic, chromium, and vanadium. The researchers found that arsenic and chromium are not in bioavailable states and posed low risk. But vanadium is in the bioavailable V5+ state and could be a long-term problem.

“Many studies that deal with red mud as an absorbent focus on the uptake of metals or nutrients,” Burke continues. “But they do not give enough consideration to the quality of the treated water—that is, is it suitable for discharge to rivers?”

Burke also has questions about the long-term stability of new mineral phases in the sulfidized material and how it will hold up when used as a sorbent. “Much more detailed work seems to be required before this material could actually be used,” Burke believes.

Futility has been the name of the game with red mud, adds geologist Katy Tsesmelis, a communications manager at the International Aluminium Institute. “We receive lots of project proposals that may have a sound scientific basis but could never be scaled up,” Tsesmelis notes. She says there are also lots of attempts made to reuse red mud that never come to light. It’s possible someone already tried sulfidized red mud.

But Tsesmelis emphasizes that the industry continues to invest in research. “The industry as a whole is working hard to remediate and reuse bauxite residue.”

Iannicelli isn’t discouraged by the lack of success so far in using red mud. He now has multiple patents for the sulfidation process and is eager to make commercial quantities of Azorb. He expects the cost to be as little as 10 cents per lb, less than half the cost of similar sorbents. And the first major application might be this year, cleaning up discolored pulp and paper mill effluent.

“I think the time is ripe to turn cheap red mud into an inexpensive material that can help solve some serious environmental problems,” Iannicelli says. “I don’t have all the answers yet. But as a chemist, I want to do good for the chemical industry.”  

Chemical & Engineering News
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Tom Harty (Wed Jun 18 09:07:06 EDT 2014)
what is the smallest volume for trial at paper/pulp plant?
Steve Ritter (Mon Jun 23 14:10:02 EDT 2014)
According to Joseph Iannicelli, he would need two liters of discharge water from a plant for a lab test to determine the concentration of AZorb required to decolorize the wastewater and to estimate the amount of AZorb needed to conduct a full-scale test. A chemical test of the decolorized water would also be required. The Rayonier mill mentioned in the story discharges 65 million gallons of water per day, he says, which would require hundreds of tons of AZorb per day.
David Thomas (Sat Apr 25 09:36:44 EDT 2015)

"Iannicelli has amassed a small fortune since he graduated from Massachusetts Institute of Technology with a Ph.D. in organic chemistry back 1955, when he helped develop a biosynthetic method to make penicillin."

What an unpleasant man. The original method of mass producing Penicillin was developed in 1940 by Florey and co, but was not patented due to ethical considerations. Mr Iannicelli evidently has no such qualms.
Steve Ritter (Sun Aug 30 16:44:54 EDT 2015)
I think you misunderstand. Iannicelli did research on making penicillin. He made his fortune working on kaolin and supplying spray-drying and magnetic separation equipment.
Steve (Fri Aug 07 14:36:05 EDT 2015)
Has anyone heard of the company Orbite and what they are preparing to do with red mud?
First large scale red mud remediation of its kind.
Going to prodution next month after building a $115,000,000 facility in Quebec.
Any comments on if their process will be succesful or not?
Steve Ritter (Mon Aug 31 11:39:20 EDT 2015)
Orbite is a Canadian company that produces alumina and other mineral products. They just received some patents for a process to treat red mud, a by-product of aluminium/alumina production. It seems this covers reprocessing red mud to extract scandium, gallium, rare earths, residual alumina, magnesium oxide, and titanium dioxide, which still leaves solid material as waste.
supriya (Fri Aug 28 02:29:29 EDT 2015)
we are going to try the process of extracting Iron from red mud, i want to know the hazards of handling?
Steve Ritter (Mon Aug 31 11:43:14 EDT 2015)
Red mud is generally handled as a hazardous material. You should consult experts such as some of those noted in the article for more information.
fozia sultana (Fri Sep 04 08:24:30 EDT 2015)
how can we calculate the ppm concenteration of elements in red mud ? or if pexi giving concentration in ppm then what will be your estimate ppm in one gram?
fozia sultana (Fri Sep 04 08:28:09 EDT 2015)
The literature everywhere showing the elemental concentration of red mud in % but not showing in how much red mud?
transgenic animals (Mon Sep 07 23:17:11 EDT 2015)
Does the red mud have chemical or biological significance.
transgenic animals
Gary McNeish (Mon Nov 09 19:36:10 EST 2015)
Red Mud can be successfully recycled. This can be done with little or no cost to the companies that produce it.
The managers of these plants around the world have up to now had to juggle the pressures from. Head office. The local community. The press. Environmentalists and local and national governments over the stockpile of Red Mud.

Now they can remove that pressure by having these stockpiles recycled. Effectively for free.

We have successfully completed tests on tyre pyrolisis waste and are opening a pilot plant in the UK. The first of its type in the world. Tests have been completed and not limited to. Compression. Tensile. Acoustic. Fire and leaching. These tests have been done on the products made with this industrial waste.

We are now in a position to offer our services in the recycling of Red Mud.

Our core products are made in the majority with Cement or on occasions with Alkali Activated Material or Geopolymer. With either 8 to 13 Ph Red Mud or Neutralised Red Mud.

Our products are but not limited to: Paving slabs and Kerbs. Block paving. Roof tiles. Drainage pipes. Turf/soil substitute growing medium. Concrete. Crash barriers. Sea defences. Roads/driveways. Other products mixed with resins and used as a colourant. Kitchen worktops. Shower trays. Fire surrounds. Etc to name but a few.

Our guarantee is that the ROI (Return On Investment) will be repaid through sales of these and other products. Effectively offering a free service for the removal and recycling of Red Mud. Now there is no reason why the companies that make Red Mud can not recycle it.

Samples available. 50 to 100 Kilo of Red Mud required shipped to UK.
Feasibility study offered, undertaken at your cost. Cost returned under guarantee if contract agreed.
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