问题 问答题 简答题

炉渣的主要成分是什么?

答案

参考答案:

炉渣成分来自以下几个方面:

(1)矿石中的脉石;

(2)焦炭灰分;

(3)熔剂氧化物;

(4)被浸的炉衬;

(5)初渣中含有大量矿石中的氧化物。

对炉渣性质起决定性作用的是前三项。脉石和灰分的主要成分是SiO2和Al2O3称酸性氧化物;熔剂氧化物主要是CaO和MgO称碱性氧化物。当这些氧化物单独存在时,其熔点都很高,高炉条件下不能熔化。只有它们之间相互作用形成低熔点化合物,才能熔化成具有良好流动性的熔渣。原料中加入熔剂的目的就是为了中和脉石和灰分中的酸性氧化物,形成高条件下能熔化并自由流动的低熔点化合物。炉渣的主要成分就是上述4种氧化物。用特殊矿石冶炼时,根据不同的矿石种类,炉渣中还会CaF2、TiO2、BaO、MnO等氧化物。另外,高炉渣中总是含有少量的FeO和硫化物。

阅读理解

Work is a part of living —my grandparents understood that. They lived and worked on a farm that has been in my family for 150 years. They raised chickens for eggs , pigs and cattle for meat . Cows were kept for milk and the cream, from which Grandma made butter and cheese. What little yard they had became a garden.

The Depression, therefore, didn’t make much change in their lives. But it did bring an unending flow of men out of work, drifting from job to job, to the farm. The first to show up at the door of the kitchen was a man in rags. He took off his hat and quietly explained that he hadn’t eaten for a while. Grandpa stood watching him a bit , then said , “There’s a stack of firewood against the fence behind the barn (谷仓). I’ve been needing to get it moved to the other side of the fence . You have just about enough time to finish the job before lunch .”

Grandma said a surprising thing happened. The man got a shine in his eyes and he hurried to the barn at once. She set another place at the table and made an apple pie. During lunch, the stranger didn’t say much, but when he left, his shoulders had straightened. “Nothing ruins a man like losing his self-respect,” Grandpa later told me.

Soon after, another man showed up asking for a meal. This one was dressed in a suit and carried a small old suitcase. Grandpa came out when he heard voices. He looked at the man and then offered a handshake.” There is a stack of firewood along the fence down behind the barn I’ve been meaning to get it moved. It’d sure be a help to me . And we’d be pleased to have you stay for lunch.” The fellow set his suitcase aside and neatly laid his coat on top. Then he set off to work.

Grandma says she doesn’t remember how many strangers they shared a meal with during those Depression days-or how many times that stack of wood got moved.

小题1:When he was asked to move a stack of firewood, the first man who asked for a meal got a shine in his eyes for he was glad that         .

A.he had found a good job

B.he would have something to eat

C.he would no longer suffer from the Depression

D.he would get what he wanted without losing his self-respect小题2:The writer’s grandfather asked those jobless men to move the stack of firewood because     .

A.he didn’t want them to have a meal free of charge

B.he had been needing to get it moved

C.he wanted to help them in his own way

D.he wanted to show them his kindness and respect小题3:The writer’s grandfather was all of the following but         .

A.kind

B.thoughtful

C.wealthy

D.sympathetic小题4:The best title for the story would be         .

A.The Depression                  B.The Pleasure of Helping Others

C.No Pains , No Gains D.Work-A Part of Living

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