Sucrose, under conditions to be described, forms with the lead oxid a diplumbic saccharate, which separates in spheroidal crystals, and has the composition corresponding to the formula C₁₂H₁₈O₁₁Pb₂ + 5H₂O. The precipitation takes place quantitively and should be conducted as follows: The substance containing the sucrose, which may be molasses, sirups or concentrated juices, is diluted with enough water to make a sirup which is not too viscous. Lead oxid suspended in water is stirred into the mass in such proportion as to give about two parts of oxid to one of the sugar. The stirring is continued for some time until the oxid is thoroughly distributed throughout the mass and until it becomes thick by the commencement of the formation of the saccharate. As soon as the mass is sufficiently thickened to prevent the remaining lead oxid from settling, the stirring may be discontinued and the mixture is left for twenty-four hours, at the end of which time the sucrose has all crystallized in the form of lead saccharate. The crystals of lead saccharate can be separated by a centrifugal machine or by passing through a filter press, and are thoroughly washed with cold water, in which they are almost insoluble. The washed crystals are beaten up with water into a thick paste and the lead separated as basic carbonate by carbon dioxid. The sucrose is found in solution in the residual liquor and is concentrated and crystallized in the usual way. Reducing sugars have a stronger affinity for the lead oxid than the sucrose, and this fact is made use of to effect a nearly complete separation when they are mixed together. In order to secure this the lead oxid is added in the first place only in sufficient quantity to combine with the reducing sugars present, the process being essentially that described above. The reducing sugars which are precipitated as lead dextrosates, lead levulosates, etc., are separated in the usual way by a centrifugal or a filter press, and the resulting liquor, which contains still nearly all the sucrose, is subjected to a second precipitation by the addition of lead oxid. The second precipitation obtained is almost pure diplumbic saccharate. In the precipitation of the sugar which is contained in the beet molasses, where only a trace or very little invert sugar is present, the sucrose is almost quantitively separated, and by the concentration of the residual liquor, potash salts are easily obtained. In this case, after the decomposition of the lead saccharate by carbon dioxid, the residual sugar solution is found entirely free of lead. Where invert sugar is present, however, in any considerable proportions, it is found to exercise a slightly soluble influence on the lead saccharate, and in this case a trace of lead may pass into solution. For technical purposes, this is afterwards separated by hydrosulfuric acid or the introduction of lime sulfid.