The invention discloses a high-efficiency energy-saving 
hydrochloric acid pickling waste liquor triple-effect negative-pressure 
graphite evaporation crystallizer, belonging to the field of 
pickling waste liquoir treatment. The 
evaporation crystallizer disclosed by the invention comprises an 
evaporation concentration unit, a feed unit, a gas condensation unit, a cooling 
crystallization unit, a 
solid-liquid separation unit, a 
mother liquor circulating unit and a vacuum unit. The 
hydrochloric acid pickling waste liquor is heated in a 
vacuum state, so that volatile 
chlorine hydride and water in the solution are evaporated together, and are condensed through the gas condensation unit to form reusable clean 
hydrochloric acid; and the concentration of the nonvolatile 
metal salt in the solution is continuously increased to form a 
metal salt supersaturated solution, and the 
metal salt supersaturated solution is cooled by the cooling 
crystallization unit, so that part of 
metal salts are precipitated in the crystalline-state hydrous 
crystal, thereby achieving the goal of separating the solute and 
solvent in the solution. The invention mainly aims to provide a high-efficiency energy-saving hydrochloric acid pickling waste liquor triple-effect negative-pressure 
graphite evaporation crystallizer which has the advantages of favorable 
antiseptic property, high 
recovery ratio and low treatment cost.