Competent high temperature melt resource treatment technology of domestic waste fly ash

Process flow chart

Environment-friendly recycled glass sand

Alloy slag

Technology is introduced：

★Pretreatment before melting

Field of fly ash, accessories into the batching system respectively corresponding to the storage tank to store, batching system through feeding device according to the quantitative will fly ash, auxiliary materials into the mixer mixing, after mixing materials by fighter hoist into granulator granulation, within the bin after molding material in forming bin waiting for melting treatment.

★High temperature molten

Melting furnace upper silo with anti-blocking vibration and weighing function, feeder according to the set number of continuous and uniform material into the melting furnace for high temperature melting. Melting furnace from top to bottom is divided into gasification area, insulation layer, molten pool, the material first through the melt furnace inlet into the melting furnace, through the gasification area falls into the upper part of the insulation layer, the insulation layer is composed of gradually rising unmelted material, the insulation layer will be separated from the melting pool and gasification area. Material in the melting furnace to complete the process of softening, deformation, melting, melting flow, water and volatile material into the gasification area from the flue gas outlet melting furnace. Melting furnace energy for electricity is the clean energy advocated by the country. The melting temperature is controlled at 1200℃ ~ 1450℃ to ensure the complete melting of the material into the furnace. The metal in the material, due to its high density, remains below the melting pool and is discharged regularly for metal smelting. Other inorganic substances with low density fall into the sealed water of the slag discharge machine through the overflow outlet, and the molten slag enters the water after rapid cooling and crushing, that is, the glass molten slag. The slag discharge system is equipped with plate heat exchanger to ensure that the slag discharge water is lower than 50℃.

★Resource utilization of molten slag

Through after the melting, most metals separated from the materials and recycled materials containing trace heavy metals form extremely stable glassy slag, such as heavy metal seal from dissolution, inorganic glass formation, density increase greatly, so the volume reduction rate can reach more than 80% of fly ash, slag heat burning rate reduction ∽ 0, achieve nontoxic emissions standards requirements. As a by-product, vitreous slag can be used for mineral powder in municipal road asphalt mixture, brick making, building wall materials, etc.

Equipment characteristics and technological methods of advanced and applicability：

· This project adopts fly ash preparation method, is to add fly ash ingredients, uniform mixing, pressing molding, its purpose is: (1) reduce the melting temperature of materials, save melting cost; (2) to ensure that the material after high temperature melting to meet the requirements of vitreous slag, the product is more safe, can be all resource utilization; (3) The molding material can prolong the storage period of non-failure of the material after mixing, and can reduce the high greenhouse ash;

· The molten energy of this project is electricity, which belongs to the clean energy advocated by China; Melting furnace does not participate in the combustion, do not need to supplement the air for reducing atmosphere, high temperature does not produce nitrogen oxides, the material itself contains nitrogen oxides are reduced; Melting furnace heating fast, high efficiency, small volume, less heat loss, low energy consumption; Melting furnace temperature in 1200℃ ~ 1450℃, material residence time > 15min, organic matter is completely decomposable with flue gas discharge, the metal density is larger at the bottom of the melting pool is regularly discharged, metal recovery benefit is good, slag metal content is low, leaching meets the standard, slag heat burn reduction rate ∽0, slag application range is wide.

· After the melting furnace is equipped with high temperature flue, adiabatic design, the residence time of flue gas at high temperature is BBB 0 2 seconds; With air supplement device, through the swirling air, so that the flue gas and air fully mixed contact, combustible burning. ◼ flue gas through the cloth bag dust collector metal ash collection and resource utilization, good efficiency, and is conducive to the purification of tail gas.

This project is mainly aimed at high-temperature melting treatment of fly ash, making it harmless, reducing, recycling and energy saving. The selected equipment and process are suitable for on-site treatment of waste production units, which covers a small area and has no transportation cost and secondary pollution risk in the transportation process. Flying ash is the waste produced by the enterprise's own domestic garbage incineration. The amount of exhaust gas generated is very small, and the existing exhaust gas treatment process does not need to be increased and adjusted. Comparison of present centralized collection of fly ash landfill disposal way and the centralized collection of fly ash melting treatment scheme is proposed, the production unit directly to the court to scrap disposal way is more suitable for hazardous waste treatment in China, the working condition of melting system stability, wide range of processing, low investment, low running cost, disposal more thoroughly, resource recovery benefit is more outstanding.

Technical highlights：

◆ wide adaptability of waste: domestic waste incineration fly ash, heavy metal containing waste can be treated;

◆ Small energy consumption: the heat source is electricity, which is clean energy, with high efficiency (up to 80%), heat energy reuse, more energy saving;

◆ Low cost of tail gas treatment: little amount of exhaust gas production, low investment cost of tail gas purification equipment, low operating cost;

◆ Low maintenance cost: the furnace body is light and small, the operation is flexible, the temperature is controllable, the loss is small;

◆ minimal waste water production: low waste water treatment costs;

◆ No solid waste generation: the preparation process (glass production batching process), vitreous slag with high quality, no need for landfill;

◆ Alloy and metal ash can be recycled: resource reuse, considerable profit;

◆ Recyclable glass sand: other inorganic materials to form glass slag, as a product widely used, green 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, less constrained by environment

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