Catalyzes the reversible cleavage of L-rhamnulose-1-phosphate to dihydroxyacetone phosphate (DHAP) and L-lactaldehyde. L-rhamnulose 1-phosphate = (S)-lactaldehyde + dihydroxyacetone phosphate Binds 1 zinc ion per subunit. Carbohydrate degradation; L-rhamnose degradation; glycerone phosphate from L-rhamnose: step 3/3. Homotetramer. Belongs to the aldolase class II family. RhaD subfamily. Could be the product of a pseudogene.