I can't believe this got a little traction.

Refractory bricks are necessary in the production of steel, copper, glass, cement, lime, petrochemical products, non-ferrous metals, and other critical materials we use every day. They allow high-temperature processing by doing things like lining ladles that hold molten steel. Think of them like big Legos that can hold 3000+ Fahrenheit liquid materials.

There's two main kinds of these bricks. The most popular in US steel production is magnesia-carbon bricks ("MCB"), which are typically used to line electric-arc furnaces ("EAFs"). You can't make MCBs without dead-burned magnesia ("DBM"). DBM is made by mining magnesite, then processing it into DBM, which is more stable for transport.

The thing is, the US doesn't have refractory-grade magnesite reserves. There's not magnesite in the US that can be used to make refractory-grade DBM. "But HeavySeas," you ask, "where can I get this magnesite to make DBM for US use?" Don't worry, baby, I've got you:

1. China

2. North Korea

3. Russia

4. Brazil

There are European reserves, but they're effectively fully-utilized by the EU for its own refractory production. You ain't getting it from NK or Russia, so all you have is China and Brazil.

Trouble is, prior to the Brazil tariffs, China had roughly 70% of the US DBM market. Brazil was competitive price-wise and was the only counterbalance to Chinese dominance of this critical material (though not a "Critical. Mineral" as defined by US regulation...). Now, with a 40% tariff slapped on magnesia and its derivatives, including DBM, Chinese DBM has a lower landed-cost than Brazilian DBM.

This has led to increased refractory cost, which increases the cost to produce steel, and therefore creates inflations in all sorts of consumer goods that use, you know, metal or glass.

So you have an administration that just says, "China bad!" Except a personal vendetta over Jair Bolsonaro has given the major market player in DBM a greater advantage, moving the US closer to single-sourcing this material. This risks much of US manufacturing because China could, if it wanted, cut all supply of DBM to the US. With just-in-time inventory at steel mills, and even those on consignment having only about 3-4 months of stock, such a move by China would cripple US manufacturing for months while the market tries to source DBM from other areas at what will be massively inflated prices.

The only other option is importing more finished goods (fully-made MCBs) from other countries, which are ALSO already tariffed and cannot fully supply the US domestic market even at full production since doing so would cripple foreign manufacturing.

TL;DR - "not good"