Solid/hazardous waste treatment solution provider
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Technical introduction

smelting solid hazardous waste treatment

Smelting hazardous wastes mainly come from arsenic containing hazardous wastes generated in the smelting process of copper, lead, zinc and tin smelters, including white smoke dust, arsenic filter cake, arsenic alkali residue, neutralization residue, etc. According to the amount of valuable metals, it can be divided into arsenic containing hazardous wastes rich in valuable metals and arsenic containing hazardous wastes poor in valuable metals. According to different classifications, we design different process ideas, aiming to treat smelting hazardous wastes with the ideas of higher comprehensive recovery rate, more stable disposal, lower processing cost, environment-friendly and environment-saving.
For the arsenic containing hazardous wastes with poor valuable metals, the comprehensive recovery value is not high. Our technical idea is to convert the hazardous wastes into arsenic compounds suitable for reducing metal arsenic after treatment, and then reduce arsenic to crude metal arsenic through reduction. The crude metal arsenic enters the rigid landfill for direct landfill.
The new hazardous waste landfill standard (implemented on December 31, 2019) clearly requires that wastes with arsenic content greater than 5% should enter the rigid landfill. Arsenic containing wastes entering the rigid landfill need to be pretreated to make them no longer reactive and flammable, and there is no requirement for leaching toxicity; Waste containing less than 5% arsenic can be pretreated to non reactivity and flammability before entering the rigid landfill. It can also be treated to the "control limit for allowable landfill of hazardous waste" and meet other requirements for entering the flexible landfill before entering the flexible landfill.

Core equipment

Batching process scheme - main equipment of intelligent batching

Technical ideas for comprehensive recovery and safe disposal of smelting hazardous wastes

For arsenic rich hazardous wastes, our technical idea is: the hazardous wastes are separated by re oxygen enriched side blowing electric furnace, the crude lead produced by the side blowing furnace is electrolytic refined, and the electrolytic anode mud is smelted to produce precious metal products; If the zinc content of the slag produced by the side blowing furnace is low, it shall be sold to the cement plant or disposed of as general solid waste. If the zinc content is high, it shall be blown in the fuming furnace. The flue gas of side blowing furnace is collected at high temperature through waste heat boiler and electric dust collection to produce lead containing indium germanium dust for small metal smelting; The flue gas after electric dust collection is collected by quenching to produce crude arsenic oxide, which is then purified, and the produced pure arsenic oxide is sold out. If the pure arsenic oxide Market is not good, the pure arsenic oxide will be reduced to metal arsenic for sale or rigid landfill. Finally, valuable metals such as lead, copper, silver and indium are fully recovered, and arsenic is opened in the form of arsenic trioxide or metal arsenic.

Batching process scheme - Intelligent batching

Smelting hazardous wastes contain complex components, arsenic and heavy metals, and some materials raise dust, which is very harmful to human body. According to the characteristics of arsenic containing hazardous wastes, Hunan Ruiyi has put forward the concept of "intelligent batching" in China. Using equipment such as pipe chain conveyor and vertical warehouse, it realizes intelligent transportation and intelligent batching from material mobilization to process links, so as to avoid material contact with human body and material landing to a greater extent, so as to achieve no dust in the site, environmental friendliness and full intelligent operation. The process scheme is planned to be adopted in the 50000 T / a comprehensive recovery and safe disposal project of valuable metals of Yunnan Ruiyi Environmental Technology Co., Ltd.

Smelting process scheme - re oxygen enriched side blowing electric furnace

The main features of this flue gas treatment process are:
1. Heavy metals are concentrated in high-temperature smoke and dust, which is collected by waste heat boiler and electric dust collector, and the collected high heavy metal smoke and dust is used to recover small metals;
2. Arsenic is enriched in low-temperature smoke and dust. The low-temperature smoke and dust is collected by the bag dust collector behind the quench tower. The collected low-temperature smoke and dust is used to purify arsenic trioxide and prepare metal arsenic.
3. Through the ionic liquid absorption system, the concentration of sulfur dioxide in flue gas is stabilized at 4% ~ 4.5%, so that it has the conditions for acid making. The tail gas of acid making can be desulfurized through the ionic liquid absorption system, so as to achieve "near zero emission" of sulfur dioxide.

Arsenic oxide purification process scheme

Arsenic trioxide is collected in the bag dust collector behind the quench tower. At this time, its purity is about 20%. The main purpose of purification is to enrich about 20% of arsenic trioxide to more than 90%.
The equipment we use is steel belt furnace, which is mainly characterized by:
(1) The whole equipment is sealed without dust and has strong environmental protection;
(2) The thickness of low temperature, oxygen free and thin material layer is designed to ensure that only arsenic trioxide volatilizes and other impurities do not volatilize;
(3) Long reaction time makes arsenic trioxide volatilize in sufficient time;
(4) Good degree of automation, no workers on duty, full computer operation;
(5) Automatic slag discharge without workers' operation.

Arsenic oxide purification process scheme

The pure arsenic trioxide collected from the cloth bag of steel belt furnace is used for arsenic reduction. We use closed arsenic reduction furnace for arsenic reduction.
The closed arsenic reduction furnace has the following characteristics:
1. Arsenic trioxide is a highly toxic substance. The closed arsenic reduction furnace has good tightness to ensure that there is no arsenic oxide overflow;
2. The overall system adopts intelligent operation, so that workers do not need to operate on site and avoid workers' contact with equipment to a greater extent;
3. The arsenic produced can be automatically packed in barrels without manual operation;
4. The direct yield of the equipment is high, reaching more than 95%.

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