Если у вас возникли сложности с курсовой, контрольной, дипломной, рефератом, отчетом по практике, научно-исследовательской и любой другой работой - мы готовы помочь.
Предоплата всего
Подписываем
Primary zinc production produces air emissions, process wastes and solid-phase wastes emissions come primarily from the zinc roasting process and consist primarily of sulfur dioxide emissions. Most emissions are recovered on site in sulfuric acid production plants, where sulfuric acid is produced.
Zinc roasters also produce particulate emissions. Particulate air emissions from primary zinc production often contain cadmium, lead and other compounds, depending on inputs. The slurry formed from the emissions control equipment is K066 hazardous waste.
The electrowinning process produces waste heat. Rather than letting the hot gas escape into the environment, some is recovered and sent to cooling towers where the steam is collected for reuse. Wastewater is produced from leaching, purification and electrowinning. The water is usually treated and discharged. Reuse opportunities may be available.
Solid wastes include acid plant slurries, sludge from electrolytic cells and copper cakes, a by-product of zinc production, from the purification cells. Much of the waste is considered RCRA hazardous waste. Anode slime from electrolytic cells consists of impurities not captured prior to the electrowinning process. The composition usually makes the slime a RCRA hazardous waste. Copper cakes are captured and sold to copper processing plants.
Secondary zinc processing produces air emissions and solid waste emissions. Air emissions come from sweating and melting. The emissions include particulates, zinc fumes, volatile metals, flux fumes and smoke, rubber, plastics and zinc scrap. Incomplete combustion products are also emitted, but are eliminated when passed through an after burner. Particulates are collected in emissions control equipment such as baghouses. The particulates are often refined for the metals.
In distillation and oxidation processes, zinc oxides in the form of dust are produced. The oxides are collected in baghouse emissions control systems. Air emissions are also common from the pyrometallurgical processes. If simple re-melting of the zinc is required, the emissions are not high. However, if the zinc requires reduction or other refinement, emissions are likely. The lower the quality of zinc scrap, the more air emission produced in the process. Air emissions are usually collected in ventilation systems. The emissions control dust is usually sold as fertilizer or animal feed.
Solid waste is present in the form of slag. The slag from secondary zinc production usually contains copper, aluminium, iron and lead. Slag is generated during pyrometallurgical processes and may be hazardous.
Primary and secondary copper processing produce similar pollutants with similar pollution prevention opportunities. Air emissions include particulates and sulfur dioxide. Particulate air emissions usually include iron and copper oxides, but many contain other metal oxides, sulfates or sulfuric acid. Particulates are usually captured using emissions control equipment. Depending on the composition of the emissions some recovery of heavy metals may be possible.
In addition, secondary copper processing produces air emissions from the removal of excess oils and cutting fluids. The air emissions are usually captured using baghouses. After-burners may also be used to fully combust products. Sulfur dioxide is usually captured using single stage electrostatic precipitation. Once captured, the sulfur dioxide is converted into sulfuric acid and sold or reused in process.
Liquid wastes from the copper processing plant include large quantities of water. Most of the water can be reused with minimal refinement. The leaching process creates some sulfuric acid liquid waste. The sulfuric acid is almost always directly reused. Electrolytic refining procedures also produce some liquid waste. This waste is usually sent to waste water treatment facilities and discharged.
|
Task 1. |
Translate into English: |
процес випалювання цинку, процес електровиділення, шлам, викидне тепло, витікання гарячого газу, електролітний елемент, штикова мідь, анодний шлам, міднопереробний завод, неповне згоряння, спалювач, вентиляційні системи, комбікорм, добрива, шлак, первинна та вторинна обробка цинку, викиди діоксиду сірки, обезводнювання (витоплювання), пиловловник.
|
Task 2. |
Speak about the types of wastes utilization you have learnt from the text. |
|
Task 3. |
Fill in the tables with the necessary information from the text: |
|
Primary zinc production |
||
|
type |
composition |
ways of utilization |
|
Zink roasting process |
||
|
air emissions |
||
|
process wastes |
||
|
solid-phase wastes |
||
|
particulate emissions |
||
|
Electrowinning process |
||
|
waste heat |
||
|
Secondary zinc processing |
||
|
Copper Processing |
||