וּמַן־דִּי־לָ֥א יִפֵּ֖ל וְיִסְגֻּ֑ד בַּהּ־שַׁעֲתָ֣א יִתְרְמֵ֔א לְגֽוֹא־אַתּ֥וּן נוּרָ֖א יָקִֽדְתָּֽא׃
凡不俯伏敬拜的，必立刻被扔進烈火熊熊的窯中。」
Rashi
a fiery furnace a pit that is made to burn rocks into lime, and that is כִּבְשָּׁן in all the Scriptures.
Ibn Ezra
[Daniel 3:6] And whoever (וּמַן - u-man)... shall be thrown (יִתְרְמֵא - yitremē): [Means] Shall be cast (yushlakh). And [it is] like [the Hebrew cognate verb in the verse]: “He has thrown (ramah) into the sea” [Exodus 15:1].