Altair SLC is able to read/write SAS7BDAT data set files but not SAS7BCAT catalog files.
Altair SLC catalogs are saved into WPCCAT files.
If you have access to the SAS language code that was used to compile the catalog, then that can be used to generate the equivalent Altair SLC catalog files.
Alternatively, if you have access to SAS then you can run SAS and use the FORMAT procedure with CNTLOUT to extract the formats from the catalog into an intermediate data set, and then you can proceed to run Altair SLC and to use the FORMAT procedure with CNTLIN to import that intermediate data into into a Altair SLC catalog library.