Chromium slag pyrolysis treatment method with high efficiency, low consumption, and low pollution

Abstract

The invention discloses a chromium slag pyrolysis treatment method capable of realizing high efficiency chromium slag treatment, and reducing emission amount of harmful substances such as tar at the same time. According to the chromium slag pyrolysis treatment method, chromium slag and straw are mixed and reacted at a high-temperature area; obtained high-temperature tar gas flows to a low-temperature area, a part of the high-temperature tar gas is cooled onto the surface of the chromium slag which is delivered to the high-temperature area, and is reacted with Cr (VI) on chromium slag surface, and the other part of the high-temperature tar gas is removed via reaction with oxygen at the low-temperature area; at the same time, because of full utilization of the tar gas, effective reduction of Cr (VI) in the chromium slag is realized, and oxidation of chromium is controlled effectively; and in addition, another by-product of the chromium slag pyrolysis treatment method, high temperature tail gas is taken as a heat source to heat the chromium slag, so that energy consumption is reduced greatly.

Description

technical field [0001] The invention is a high-efficiency, low-consumption and low-pollution pyrolysis treatment method for chromium slag. Through process control, Cr(VI) in chromium slag can be efficiently reduced, and at the same time, the emission of tar gas and other harmful substances in tail gas can be greatly reduced, and at the same time, the Energy saving. The invention belongs to the technical field of environmental protection. Background technique [0002] Chromium slag is a by-product emitted during the production of dichromate. Because it contains water-soluble Cr(VI), it is extremely toxic. If it is stacked in the open air without treatment, it will cause varying degrees of pollution to groundwater sources, rivers or sea areas, and seriously endanger human health and the growth of animals and plants. [0003] Generally speaking, the current detoxification methods for chromium slag (i.e. changing highly toxic Cr(VI) to Cr(III)) are divided into two categories:...

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Problems solved by technology

However, this process has many defects. On the one hand, because the process mixes organic matter and chromium slag in the low-temperature area, during the movement of the two to the high-temperature area, the organic matter in the sludge will continuously produce tar gas and enter the tail gas along the airflow, while the tar gas Contains a large amount of carcinogens such as polycyclic aromatic hydrocarbons, and is easily discharged in the form of PM2.5 during the cooling process, which is extremely harmful, so its pollution problem needs to be paid attention to

On the other hand, the tar gas produced by the organic matter in this process is diluted by the high-temperature gas flow, resulting in a decrease in the concentration of reducing gases in the gas flow, which reduces the Cr(VI) reduction efficiency.

In addition, the high-temperature gas flow required by the process needs to strictly control the reduction conditions, which increases the tedious process control on the one hand, and wastes energy on the other hand

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