I have to admit I did not properly understand the scheme until I read the paper cited in the article.
Molten silicon (the element, not the oxide aka silica or sand) is being pumped around by electromagnetic arrangements with no moving parts apart from the molten silicon. Its "low" temperature is 1,500C and its high temperature 2,900C. Radiation and "solar" cells are a plausible way of extracting energy from the high temperature phase, rather than traditional heat exchangers.
Years ago I worked on software for a nuclear power station. The CO2 reactor coolant then generated steam at 800C -- red heat -- and high pressure.