Method for recycling metal and combustibles from domestic waste incineration slag

Abstract

The invention relates to a method for recycling metal and combustibles from domestic waste incineration slag, and belongs to the field of the solid waste harmless and recycling technology. By means of multi-stage gradient magnetic separation, separation of magnetic metal in the slag is achieved. By means of two-stage eddy current, nonferrous metal in the slag is separated and recycled. According to the grain size distribution and chemical morphological characteristics of the metal in the slag, the metal is crushed and screened in multiple steps so that separated slag particles can be uniform, the recycling rate of magnetic separation and eddy current separation is effectively increased, and finally, according to the density difference of materials, air separation is used for recycling the combustibles in the slag. Finally, the magnetic separation recycling rate of iron in the technological process is 60-80%, the recycling rate of the nonferrous metal aluminum is 60-70%, the recycling rate of the nonferrous metal copper is 40-50%, and separation of the metal in the slag and slag particles can be effectively achieved. The separated metal products can be directly sold or sold after refining, the combustibles can serve as waste incinerator fuel, and the remaining slag can be used as building materials.

Description

technical field [0001] The invention relates to the technical field of solid waste harmlessness and resource utilization, in particular to a method for recovering iron, aluminum, copper and other metals and combustibles from domestic waste incineration slag. Background technique [0002] Domestic waste incineration slag is a by-product of domestic waste incineration, accounting for 15%-25% of the mass of incinerated waste. In 2013 alone, the output of domestic waste incineration slag in my country has exceeded 9 million tons, which has brought huge pressure on its disposal and management. Slag is a mixture of molten slag, cullet, ceramic and masonry debris, magnetic and non-ferrous metals, unburned organic matter, and more. At present, the main disposal and utilization methods of slag are direct landfill or utilization of low-value building materials, including road aggregates, cement / concrete substitute aggregates, landfill covering materials, etc. However, considering th...

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Problems solved by technology

The common problems of these methods are that 1) they all use the method of natural mineral separation, and some metals are directly recovered by gravity separation; due to the complex and uneven composition of slag, the distribution characteristics are quite different from those of ore, and gravity separation recovers metals. The impurity content is high, which cannot meet the requirements of re-smelting

2) Without multi-stage magnetic separation, magnetic (iron) metals adhering to impurities may be mixed into non-ferrous (non-magnetic) metals, so that these recycled materials cannot be purified through the re-smelting process

3) The combination of crushing and screening is unreasonable, which affects the stripping effect of metal and sundries

4) There is no or only part of the slag for winnowing treatment, and the separation of combustibles is not complete, which affects the subsequent use of building materials for the slag

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