I have large csv file 200mb size. Try convert to xslx- but its not convert all rows (70k rows).
TxtLoadOptions opts = new TxtLoadOptions();
opts.Separator = (';');
opts.MemorySetting =(MemorySetting.MemoryPreference);
Workbook workbook = new Workbook();
var ws = workbook.Worksheets.Add("res");
ws.Cells.ImportCSV("input.csv", opts,1,1);
workbook.Save("output_out.xlsx");