You mention racemiztion of ppa with HCl I don`t recommend this see Patent US2214034 (http://l2.espacenet.com/dips/viewer?PN=US2214034&CY=gb&LG=en&DB=EPD)
for an alternative. This is because of aziridine formation during HCl reflux.
This patent will provide a method which according to the aurthor, The hydrogen gas liberatied during racemization serves to protect the ephedrines from decomposition.
Some info on use of tartaric is found in this
Patent US5962737 (http://l2.espacenet.com/dips/viewer?PN=US5962737&CY=gb&LG=en&DB=EPD)
Abstract:Stereospecific synthesis of the racemic threo isomers of 2-nitro-1-phenylpropanols by reacting a benzaldehyde derivative with nitroalkane in the presence of a tertiary amine and reducing 2-nitro-1-phenylpropanols with, for example, lithium aluminum hydride to 2-amino-1-phenylpropanols is described. Also described are phase transfer resolution of racemic mixtures of 2-amino-1-phenylpropanol and its derivatives into their optically pure isomers by reacting a racemic mixture with the mono alkali metal salt of a tartaric acid ester in a two phase system of a hydrocarbon and water. The specification further describes therapeutically useful optically pure isomers of threo-2-amino-1-(dialkoxy or alkoxy) phenylpropanols and acid addition salts thereof.