问题 问答题 简答题

何谓增压烧结?

答案

参考答案:

增压烧结是指在抽风负压不变时,用空气压缩机提高料层上面的供气压力、相应地增大ΔP,提高通过料层风量的烧结方法。该法最初是前苏联学者于1966年提出的,并在烧结盘上进行过工业试验,取得提高垂直烧结速度的显著效果。整个设备罩在密封罩内,混合料的装入和成品矿的卸出均通过圆锥形料钟和给(排)料漏斗(或经阀门系统)来实现。试验研究表明,料层上面的空气压力提高0.6个大气压,烧结机的生产率增加两倍。但是,由于增压烧结工艺使烧结设备的操作复杂化,因此在烧结机上应用仍然有困难,需要进一步研究改进。

阅读理解

阅读理解。

     The earth is about 4,600 million years old. Modern man has lived on the earth for only 35,000 years, but

during that time, we have changed our planet in many ways. Many of the things that we have done are good, but

more are not good for the earth.

     Water pollution

     A lot of people, birds and fish die each day because of water pollution. Factories have polluted the land and

the water. As a result, many rivers and lakes are now dead.

     Air pollution

     In big cities, factories, as well as cars, trucks and buses are the main cause of air pollution. Many people in

cities now have serious health problems. For example, Mexico city used to be a beautiful sunny capital, but today

it is always covered by thick brown clouds.

     Soil pollution

     In order to have a good harvest, most of the farmers use chemicals too much in their fields. That's bad for

the soil. But this kind of pollution is difficult to stop.

     Hope for the future

     These problems are very serious for our future, so all of us should do something to improve our

environment. If we can stop pollution, our planet will become more and more beautiful and our health will be

better. Let's be greener people!

1. _____ have made the earth change a lot. [ ]

A. Human beings

B. Animals

C. Plants

D. People in other planets

2. There are _____ kinds of pollution in this passage. [ ]

A. two

B. three

C. four

D. five

3. Pollution isn't a big problem now, is it? [ ]

A. Yes, it is.

B. No, it isn't.

C. Yes, there is.

D. No, there isn't.

4. Which sentence is NOT right according to the passage? [ ]

A. Most of things that we have done are good for our planet.

B. We must stop the factories from pouring waste water into the rivers and lakes.

C. Because of water pollution, many rivers and lakes are now dead.

D. Water pollution is very serious nowadays.

5. Which sentence is RIGHT? [ ]

A. Though Mexico city is always covered by thick brown clouds, it's still a beautiful sunny capital.

B. Air pollution can make people sick.

C. Now fewer farmers use chemicals in the fields.

D. Factories, cars, trucks and buses are the main cause of soil pollution.

选择题