问题 问答题 简答题

转炉用白云石或菱镁矿的作用是什么,对白云石和菱镁矿有什么要求?

答案

参考答案:

(1)白云石是调渣剂,有生白云石与轻烧白云石之分。

生白云石的主要成分为CaCO3•MgCO3。经焙烧可成为轻烧白云石,其主要成分为CaO、MgO。根据溅渣护炉技术的需要,加入适量的生白云石或轻烧白云石保持渣中的MgO含量达到饱和或过饱和,以减轻初期酸性渣对炉衬的蚀损、使终渣

能够做黏,出钢后达到溅渣的要求。

对生白云石的要求是ωMgO>20%,ωCaO≥29%,ωSiO2≤2.0%,烧减≤47%,

块度为5~30mm。

由于生白云石在炉内分解吸热,所以用轻烧白云石效果最为理想。对轻烧白云石的要求是ωMgO≥35%,ωCaO≥50%,ωSiO2≤3.0%,烧减≤10%,块度为

5~40mm。

(2)菱镁矿也是调渣剂,菱镁矿是天然矿物,主要成分是MgCO3,焙烧后用做耐火材料。对菱镁矿的要求是ωMgO≥45%,ωCaO<1.5%,ωSiO2≤1.5%,烧

减≤50%,块度为5~30㎜。

(3)MgO-C压块是吹炼终点碳低或冶炼低碳钢溅渣时的调渣剂,由轻烧菱镁矿和碳粉制成压块,一般ωMgO=50%~60%,ωC=15%~20%,块度为10~30mm。

阅读理解

阅读理解。

     阅读下面的短文,请根据短文后的要求将答案答题(请注意问题后的要求)。

     The Internet has opened up a whole new online world for us to meet, chat and go where

we've never been before. But just as in face-to-face communication, there are some rules of

behavior that should be followed when online.

     The basic rule is simple: treat others in the same way you would want to be treated. Imagine

how you'd feel if you were in the other person's shoes. For anything you're about to send: ask

yourself, "Would I say this to the person's face?" If the answer is "no", rewrite and reread.

Repeat the process till you feel sure that you'd feel comfortable saying the words to the

person's face.

     If someone in the chat room is rude to you, your instinct(本能反应)is to fire back in the

same manner. But try not to do so. You should either ignore the person, or use your chat

software to block their messages. If it was caused by disagreement with another member,

try to fix the situation by politely discussing it. Remember to respect the beliefs and opinions

of others in the chat room.

     If you do decide to tell someone in the chat room about a mistake, point it out politely. At

the same time, if you find you are wrong, be sure to correct yourself and apologize to those that

you have offended.

     It is not polite                such as their age, sex, and marital status. Unless you know the person

very well, and you are both comfortable with sharing personal information, don't ask such questions.

1. What's the best title of the passage? (Please answer within 10 words.)

                                                                               

                                                                              

2. Why should we ask ourselves "Would I say this to the person's face?" when we are to send a

     message online? (Please answer within 20 words.)

                                                                               

                                                                              

3. Please fill in the blank in the last paragraph to complete the sentence.(Please answer within

    10 words.)

                                                                              

4. Which rule do you think is the best? Why? (Please answer within 30 words.)

                                                                               

                                                                              

5. Translate the underlined sentence in the first paragraph into Chinese.

                                                                               

                                                                              

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