Method of simultaneously recycling plastics and detoxifying chromite ore processing residue by residual heat from steel slag

A method of simultaneously recycling plastics and detoxifying a chromite ore processing residue by residual heat of a steel slag, comprising following steps:

• (1) pouring the steel slag, which is in liquid state at 1500° C. to 1700° C. from a slag ladle into an inlet end of a wheeled feeder;
• preliminarily crushing the steel slag, and feeding the steel slag that has been crushed from an outlet end of the wheeled feeder to an inlet of a roller crusher;
• mixing the steel slag, that has been crushed, with plastics, and then pyrolyzing the plastics to obtain a plastic pyrolysis gas and a plastic pyrolysis coke;
• conveying the steel slag and the plastic pyrolysis coke to an outlet end of the roller crusher, and then cooling the steel slag by a cooling water;
• discharging the steel slag;
• (2) spraying the cooling water from step (1) onto the surface of the steel slag at the outlet end of the roller crusher, wherein the cooling water becomes a water vapor;
• controlling the water vapor to flow in a direction opposite to a flow of the steel slag wherein heat is exchanged between the water vapor and the steel slag;
• conveying the water vapor to the inlet end of the roller crusher, and then mixing the water vapor with the plastic pyrolysis gas to produce a mixed gas;
• conveying the mixed gas to the wheeled feeder, wherein heat is exchanged between the mixed gas and the steel slag, producing a mixed gas at 1000° C. to 1400° C.;
• (3) conveying the mixed gas from step (2) to a catalytic reforming furnace, wherein the catalytic reforming furnace is loaded with a calcined chromite ore processing residue;
• heating the calcined chromite ore processing residue with the mixed gas, and catalytically reforming Chromite Ore Processing Residue at 800° C. to 1200° C. to generate an energy gas;
• (4) conveying the energy gas from step (3) to a head of a rotary kiln, wherein heat is exchanged between Chromite Ore Processing Residue and the energy gas;
• continuously conveying Chromite Ore Processing Residue from a tail of the rotary kiln, and then reducing Cr6+ in Chromite Ore Processing Residue into Cr3+ by the energy gas;
• discharging the energy gas from the tail of the rotary kiln to a condensation device after a temperature of the energy gas is below 250° C.;
• controlling the energy gas to flow in a direction opposite to a flow of the cooling water wherein heat is indirectly exchanged;
• condensing, dehydrating and gathering the energy gas;
• and
• (5) discharging Chromite Ore Processing Residue from step (4) from the head of the rotary kiln into a cooling device;
• cooling Chromite Ore Processing Residue below 150° C. by the cooling water wherein a water vapor is generated;
• discharging the cooled chromite ore processing residue, and then controlling a gas pressure in the cooling device to be 0-30 kp higher than the gas pressure in atmosphere by the generated water vapor.