Process for reducing ramsbottom carbon test of asphalt

A process for the preparation of a hydrocarbon mixture having an RCT of (a) %w and an initial boiling point of T.sub.1 .degree.C., wherein a mixture of an asphaltic bitumen I obtained in the solvent deasphalting of a distillation residue from a crude mineral oil, which asphaltic bitumen I has an RCT of (b) %w and an average molecular weight M, and an asphaltic bitumen II separated in the solvent deasphalting of a residue obtained in the distillation of a hydrotreated residual fraction of a crude mineral oil, which asphaltic bitumen II has an RCT of (c) %w, which mixture comprises less than 50 pbw of asphaltic bitumen II per 100 pbw of asphaltic bitumen I, is subjected to a catalytic hydrotreatment with the object of reducing the RCT;

• the product obtained is separated by distillation into an atmospheric distillate and an atmospheric residue having an initial boiling point of T.sub.1 .degree.C.;
• either from the atmospheric residue so much asphaltic bitumen is separated by solvent deasphalting that a deasphalted atmospheric residue having the desired RCT of (a) %w is obtained, or the atmospheric residue is separated by distillation into a vacuum distillate and a vacuum residue, from which vacuum residue so much asphaltic bitumen is separated by solvent deasphalting that a deasphalted vacuum residue is obtained having an RCT which is such that, when this deasphalted vacuum residue is mixed with the vacuum distillate, a mixture is obtained which has the desired RCT of (a) %w;
• and the catalytic hydrotreatment is carried out under such conditions as to satisfy the relation:
• ##EQU6## where ##EQU7## d=the RCT of the mixture of asphaltic bitumen I and asphaltic bitumen II, e=the RCT of the atmospheric residue with an initial boiling point of T.sub.1 .degree.C. of the hydrotreated product, and
• r=the number of pbw of asphaltic bitumen II per 100 pbw of asphaltic bitumen I present in the feed mixture.