NOVELTY - Recycling slag comprises e.g. (i) dehydrating the water content to 80-85% from the slag mud using a hopper (1), then transferring into a spiral presser (2) for dehydrating or pressing, obtaining the water content of the slag as 20-30%, then transferring into microwave drying device (3) and drying, to obtain water content of 5-8%, where the temperature of slag is 100-120 degrees C, condensing the liquid obtained from the microwave drying device to vapor form using a condenser (4) and then transferring to spiral presser, to obtain a filtrate, that is collected in the collection tank (5).    USE - The ash is used as a agriculture fertilizer (claimed).    ADVANTAGE - The method can accelerate the reaction speed, increase the thermal efficiency, increase the gas production rate and is economical.    DETAILED DESCRIPTION - Recycling slag comprises (i) dehydrating the water content to 80-85% from the slag mud using a hopper (1), then transferring into a spiral presser (2) for dehydrating or pressing, obtaining the water content of the slag as 20-30%, then transferring into microwave drying device (3) and further drying, to obtain water content of 5-8%, where the temperature of slag is 100-120 degrees C, condensing the liquid obtained from the microwave drying device to vapor form using a condenser (4), then transferring to spiral presser, to obtain a filtrate, that is collected in the collection tank (5), and then carrying out waste water treatment; (ii) preheating by transferring the slag from microwave drying device into a pre-heater, carrying out pre-heating process, and transferring to a gasification furnace, where the temperature of preheating slag outlet is 300-400 degrees C; (iii) carrying out gasification by filling small amount of oxygen as gasifying agent in the gasification furnace, where the gasification temperature is 950-1100 degrees C and the gas generated from the products during the process is 63-70%; (iv) separating the gasification product by transferring the vaporized product into a separator I, then transferring the separated air into the air pre-heater to pre-heat the air, and separating the liquid and solid products, then transferring into a combustor; (v) purifying gas by transferring the gas from the air pre-heater into the gas purifier, purifying by removing impure gas, to obtain combustible gas, collecting the combustible gas into a collecting tank, where the amount of : hydrogen gas is 35-40%, carbon monoxide is 30-34%, carbon dioxide is 15-18%, methane gas is 10-12%, 2-4% CnHm gasoline and the calorific value of the combustible gas is 14.8-15.7 MJ/m3; (vi) transferring the solid-liquid products of combustion gas from the separator I to the combustor, carrying out in air environment under the fixed carbon and biological oil combustion, at high temperature, generating smoke gas, transferring the smoke gas into a separator II, separating ash, where the ash is transferred to combustor and the smoke is transferred to gasification furnace to supply heat and (vii) composting ash by transferring the ash from combustor to a fertilizer processing tank for processing ash to a agricultural fertilizer.    DESCRIPTION OF DRAWING(S) - The drawing shows a schematic representation of a device utilized in the above mentioned method.    Hopper (1)    Spiral presser (2)    Microwave drying device (3)    Condenser (4)    Collection tank (5)