science Regarding Mafic Lava

[Tornadopelt 33]

Okay, so if anyone's been paying attention to the news recently, you may have heard that Kilauea has been erupting again - thankfully, it seems that this eruption is, so far, nothing like what 2018 brought us. However, news of the Kilauea eruption did bring something to the forefront of my mind. I'd often had "shower thoughts" of utilizing the outputs of volcanoes for different things, but this was the first time I gave the idea some serious thought, and it revolves around mafic lava.

There are three (technically four) types of lavas - first, your felsic lavas, the ones high in silica content. These are responsible for the more famous explosive eruptions like Mt. St. Helens, Tambora, and Vesuvius. Then you have intermediate lavas, ones with a more moderate silica content of the three well-known lavas, and tend to be somewhere in the middle. And finally, you have mafic lavas - fluid lavas with relatively low silica content and a high ferromagnesian content. There were ultramafic lavas before, but the mantle's no longer hot enough to produce those.

Me and a friend hashed this out - namely, cooling the mafic lava via seawater (dual-purpose), crushing the mafic rock into mafic sand and then mafic dust, then using HCl to leach out the metals in the form of MgCl₂, FeCl₂, and FeCl₃, along with other metal chlorides. Those can then be either reduced directly via hydrogen and then melted, or converted into oxides and then smelted, after which the resulting metals can be poured into ingots and sold. My question is such: would it be possible to pull all of this off from a chemistry and physics perspective, and would it be worth the money needed to do such a thing if it is possible?