Public opinion studies suggest that Brazilian presidential candidate Jair Bolsonaro is likely to win Sunday's election.

The candidate believes he knows of a resource that may help his nation's economy: niobium.

Niobium is a metal that is added to steel to make it stronger and lighter. It is in high demand by carmakers, space travel companies and in many other industries.

Brazil produces about 85 percent of the world's supply of niobium. Bolsonaro wants to keep Brazil's market position.

In 2016, Bolsonaro made a 20-minute YouTube video about the value of the metal and how it could be a large part of Brazil's economy in the future.

Brazil's military dictatorship, which ruled from 1964 to 1985, wanted to protect natural resources, such as oil and minerals, from foreign companies.

Bolsonaro is a former military officer. He has long supported the idea of a military-led government. But he has said he supports free-market economics as a presidential candidate.

Supporters of Jair Bolsonaro, far-right lawmaker and presidential candidate of the Social Liberal Party (PSL), attend a demonstration in Rio de Janeiro, Oct. 21, 2018.

The 2016 video was recorded at a mine owned by a privately-held Brazilian company known as CBMM. Bolsonaro praised CBMM for its jobs that pay well, its private pre-school and other support the company provides for its workers.

He added that Brazil would be better off if it supported CBMM's method of development and centered its efforts on "future applications" of niobium.

The same year, the Chinese company China Molybdenum Co. Ltd., or COMC, bought a niobium mine 200 kilometers away from CBMM.

Bolsonaro is believed to be the first presidential candidate to make niobium a campaign issue. Speaking on national television in August, he criticized the CMOC purchase.

He said, "It's something only we have, we should invest in technology and research to use this mineral. Instead we sell and deliver the mine to them."

Mining experts say Bolsonaro's niobium fears are exaggerated.

Hugo Nadler is a former CBMM executive. He says CMOC's Brazil mine makes up just 10 percent of the global market.

That leaves about 75 percent to Brazil's CBMM. In a statement, CBMM told Reuters it is the only company that sells in all parts of the niobium market. That includes products used to make airplanes and superconductors.

CBMM said there is a lot of potential for expanding the use of niobium in applications such as car batteries and other products.

Nadler said, if the niobium market grows, it is unlikely to have much of an effect on an economy the size of Brazil's.

"Mining makes up 5 percent of GDP, if you take the portion that is niobium, it's nothing," he said.

GDP is the most used measure of all the goods and services produced within a country.

But Bolsonaro remains a believer.

In his video, he said, "[Niobium] can give [Brazil] economic independence."

Jake Spring reported this story for the Associated Press news agency. Jonathan Evans adapted it for Learning English. Mario Ritter was the editor.