The technology of calcination of materials in high temperature rotary furnace with eddy current self-heating

Eddy current self-heating tailings and tailings recycling technology - process flow chart

Live photo of material calcination in eddy current self-heating high temperature rotary furnace

Technology is introduced：

★Pretreatment of raw materials

The raw material in the silo is sent into the raw material silo of the batching system through the belt conveyor, and the activator and additive are prepared according to the set quantity through their respective silo weighing and feeding systems. Then by the belt conveyor into the two-shaft mixer for uniform mixing. The mixed material is sent to the ball press for molding. Then through the belt conveyor and bucket elevator to the top of the vortex self-heating high temperature rotary furnace silo, complete the pretreatment of raw materials. The whole process is completed in a closed environment without exhaust gas leakage. After starting the machine, the raw material can be pretreated automatically according to the set requirements in the whole process, without manual intervention, only regular inspection can be done, with a high degree of automation.

★Calcination of raw materials and metal activation, magnetization reaction

Eddy current self-heating type high temperature rotary furnaces at the top of the bin with the function of prevent vibration and weighing metering, bin exports and imported equipment for the feeder airtight, feeder exports and eddy current self-heating type high temperature rotary furnaces inlet airtight cohesion, feeder according to the set quantity continuously even after molding material into the vortex of autothermal reforming high temperature rotary furnaces calcination and activation, magnetization response. The material in the eddy current self-heating high temperature rotary furnace from front to back through preheating, medium temperature reaction gasification, high temperature reaction gasification, cooling into the slag hopper. Through the screw conveyor and belt conveyor sent to the vibrating feeder, continuous into the mill, the crushed material through the magnetic separator, sorting out the concentrate and tailings. Concentrates are sent to smelting units for resource utilization. The content of metals in the tailings is trace, which is completely incinerated by high temperature organic matter. It is non-toxic and harmless, and can be used as resource utilization of building materials. Complete the material harmless and metal activation, magnetization, separation and resource utilization. The eddy current self-heating high temperature rotary furnace adopts electric heating, which is a clean energy advocated by the state. It produces little waste gas, heating up fast, and temperature control is simpler. The metals in the raw material can be heated up quickly and enter the state of activation and magnetization reaction. The eddy current self - heating high - temperature rotary furnace adopts the counter - current type, more energy saving. The vortex self-heating high temperature rotary furnace is under negative pressure, no dust leakage.

★Waste gas treatment and metal collection

After the exhaust gas passes through the cyclone dust collector, bag dust collector, water rotary spray tower, electric mist dust collector and mist eliminator dust collector, it enters the activated carbon adsorption box for odor removal, and then passes through the desulfurization and denitration device, and is sent into the exhaust tube by the induced draft fan for discharge to the standard. The high content metal ash collected by the cyclone and bag dust collector is sent to the smelting unit for resource recovery, and the wastewater from the water rotary spray tower and electric fog dust collector is precipitated, filtered and collected for metal purification.

Equipment characteristics and technological methods of advanced and applicability：

· This project by accurately adding activator to raw materials: ① accelerate the metal activation, magnetization reaction speed; ② increase the metal separation rate, up to 70-98%; ③ reduce energy consumption.

· The start-up energy of this project's eddy current self-heating high temperature rotary furnace is electricity, which belongs to the clean energy advocated in China. The eddy current self-heating high temperature rotary furnace produces less waste gas and takes away less heat, saving the cost of activation of raw materials and separation of magnetized metals. The eddy current self-heating high temperature rotary furnace is countercurrent. The air is heated through the material cooling area, and then heated in the high temperature area. Then the heat is transferred to the preheating area to the new material in the eddy current self-heating high temperature rotary furnace, and the energy is reused in large quantities. The eddy current self-heating high temperature rotary furnace has the characteristics of fast temperature rise, high efficiency, small volume, less heat loss and low energy consumption. According to the material requirements, the temperature and the speed of the eddy current self-heating high temperature rotary furnace can be controlled freely.

· The Fe2O3 in the material can be transformed into magnetized Fe3O4 by heating and controlling oxygen in the eddy current self-heating high temperature rotary furnace. The Fe3O4 in the material can be separated effectively by magnetic separation.

· The amount of exhaust gas is small, and the metal can be separated and recycled through the dust removal system of exhaust gas purification, and the metal content in the exhaust gas can be reduced at the same time, and the exhaust gas treatment is simpler.

· This project not only can be used to solid waste (tail slag, tailings), and can be used to contain heavy metals (including precious metal elements) of waste and undressed ore resources disposal, reuse disposal of the material and metal elements, and greatly reduce the processing in the process of "three wastes" emissions, do material recycling use, wastewater recycling, flue gas emissions standards.

· This technological breakthrough the original blast furnace and the calcining rotary kiln technology, reduction of separation method using coal, gas heating of the low recovery efficiency, high energy consumption, high pollution emissions of the bottleneck, realize the calcining process of high efficiency, low energy consumption, low emissions, to harmless, reduction and recycling, production energy conservation purposes. The selected equipment and process are suitable for on-site self-treatment of waste production units, which covers a small area, has no storage cost and transportation cost, and avoids the risk of secondary pollution in the transportation process. The direct on-site self-disposal of waste production units is more suitable for the treatment of solid waste in China, and the eddy current self-heating tailings and tailings resource reuse treatment technology. Stable working condition, wide range of treatment, low investment, low operating cost, more thorough treatment and disposal, more prominent recycling benefits.

Technical highlights：

◆ wide adaptability of waste: tailings, tailings, raw ore and dangerous waste can be treated;

◆ High efficiency: heat source is electricity, clean energy, eddy self-heating type, high efficiency (up to 80%);

◆ Low energy consumption: countercurrent design, good use of waste heat, more energy saving;

◆ Low cost of tail gas treatment: less waste gas production, low investment of tail gas purification equipment, low operating cost;

◆ Low maintenance cost: easy installation, flexible operation, temperature control, small loss;

◆ Very little waste water production: waste water can be recycled, low disposal cost;

◆ No solid waste generation: The tailings are non-toxic and harmless, and the products are widely used without landfill.

◆ Metal ash can be recycled: Resources reuse, considerable profits;

◆ High degree of automation: PLC design, flexible operation, low labor intensity, safer;

◆ Flexible process control: reaction temperature and residence time (speed) can be set according to the requirements of raw materials.

◆ High degree of automation: PLC design, flexible operation, low labor intensity, safer;

◆ The project construction period is short: 9 ~ 12 months, small area, combined type, small area, small environment constraint.

Technology to compare：

The traditional coal burning blast furnace and natural gas rotary kiln need to introduce a large amount of air to assist combustion in the combustion process. The eddy current self-heating technology does not need to transport a large amount of air to the kiln, and the whole calcination process will not produce a large amount of flue gas and dust containing high concentration of carbon dioxide. It reduces carbon emissions, reduces environmental pollution, and reduces the energy taken away by exhaust gas. Reduce the investment cost of exhaust gas equipment and operating cost of exhaust gas treatment.

The amount of waste gas produced by traditional natural gas rotary kiln calcination is 21 times that of this project; Waste gas heat removal is 6.2 times of the project.