NOVELTY - Apparatus comprises storage tank (1), inlet valve (2), high-pressure piston pump (3), outlet valve (4), heat exchanger (5), gas-liquid flow valve (6), gas-liquid separator tank (7), wet gas flow meter (8), liquid flow meter (9), back-pressure valve (10), supercritical reactor (11), monoammonium phosphate reaction tank (12), low speed stirring motor M (13), magnesium chloride storage groove (14), potassium dihydrogen phosphate storing groove (15), pressure adjusting valve (16), control valve of magnesium chloride (17) and potassium dihydrogen phosphate control valve (18).    USE - Used for recovering nitrogen and phosphorus in the form of magnesium ammonium phosphate used as fertilizer during supercritical extraction of blue algae (claimed).    ADVANTAGE - The apparatus ensures fast recovery, low energy consumption and 90% efficiency.    DETAILED DESCRIPTION - Apparatus comprises storage tank (1), inlet valve (2), high-pressure piston pump (3), outlet valve (4), heat exchanger (5), gas-liquid flow valve (6), gas-liquid separator tank (7), wet gas flow meter (8), liquid flow meter (9), back-pressure valve (10), supercritical reactor (11), monoammonium phosphate reaction tank (12), low speed stirring motor M (13), magnesium chloride storage groove (14), potassium dihydrogen phosphate storing groove (15), pressure adjusting valve (16), control valve of magnesium chloride (17), potassium dihydrogen phosphate control valve (18), quantitative magnesium chloride feeder (19), potassium dihydrogen phosphate quantitative feeder (20), drying room (21), pH-line monitor (22), pool (23), monoammonium phosphate crystal conveying valve (24), solid-phase ascillator (25), acid storage groove (26), acid control valve (27), quantitative meter D (28), acid output valve (29) and control valve (30).    An INDEPENDENT CLAIM is included for a method for recovering nitrogen and phosphorus during supercritical extraction of blue algae, which involves:    (A) recovering blue algae extract in supercritical reactor using high pressure plunger pump;    (B) stopping the reaction for 3-5 minutes;    (C) pre-heating extract using heat exchanger;    (D) conveying pre-heated material in gas-liquid separator tank to separate gas and liquid, where liquid phase is rich in nitrogen;    (E) adjusting solid-phase product in a control valve using supercritical reactor, solid phase oscillator, acid storage tank, acid control and quantitative meter D;    (F) storing solid product;    (G) conveying liquid phase in monoammonium phosphate reaction tank;    (H) monitoring pH of liquid using alkali liquid of pool;    (I) feeding magnesium chloride and potassium dihydrogen phosphate dry powder using quantitative feeder D in monoammonium phosphate reaction tank;    (J) dissolving precipitate using low speed-stirring motor;    (K) processing monoammonium phosphate in reaction tank using first output pipe and second input; and    (L) removing gas phase as waste heat using drying room.    DESCRIPTION OF DRAWING(S) - The drawing shows a schematic diagram of apparatus.    Storage tank (1)    Inlet valve (2)    High-pressure piston pump (3)    Outlet valve (4)    Heat exchanger (5)    Gas-liquid flow valve (6)    Gas-liquid separator tank (7)    Wet gas flow meter (8)    Liquid flow meter (9)    Back-pressure valve (10)    Supercritical reactor (11)