Some variations provide an automated system for solvent extraction of a feed stock to produce a botanical extract, fats, oils, or other desirable solute, comprising : an extraction reactor; a distillation unit; and a second-stage purge chamber or a second-stage purge process utilizing the extraction reactor itself. The second-stage purge chamber or process receives or holds the solid material along with a heated inert non-condensable gas and/or solvent vapor, to recover residual solvent contained in the solid material. Other variations provide a process comprising : feeding a raw material and a solvent into an extraction reactor; generating dissolved material in rich solvent and extracted solid material; distilling the rich solvent to generate purified product and recovered solvent; conveying the solid material and a heated inert non-condensable gas and/or solvent vapor into a second-stage purge chamber, or holding the solid material in the same vessel, to recover residual solvent; and recovering the purified product.