This .vol file has a human-readable header. From that you can determine image geometry (size, spacing, origin) and write it to a header file. You can then open that file in Slicer.
For example, here is the header for the file you shared:
# Complete NRRD file format specification at:
sizes: 504 501 500
space directions: (0.08,0,0) (0,0.08,0) (0,0,0.08)
kinds: domain domain domain
space origin: (0,0,0)
byte skip: 800
data file: CT_0.vol
If you save the content above to a file named
CT_0.nhdr (or download it from here) then you can open that file in Slicer.