化学专业英语翻译4

IIIB

—

VIIIB ELEMENTS

Group

I-B

includes

the

elements

scandium,

yttrium,

lanthanum,

and

actinium

1

, and the two rare-earth series of fourteen elements each

2

—

the

lanthanide and actinide series. The principal source of these elements is the

high

gravity

river

and

beach

sands

built

up

by

a

water- sorting

process

during

long

periods

of

geologic

time.

Monazite

sand,

which

contains

a

mixture of rare earth phosphates, and an yttrium silicate in a heavy sand are

now commercial sources of a number of these scarce elements.

B

组包括元 素钪，钇，镧，和

actinium1

，和

2

稀土系列十四

each2

镧系和 锕系元素的系列。

这些元素的主要来源是重力高与海滩砂建立

起 来的

water-sorting

过程在漫长的地质年代。独居 石砂，其中包含

一个混合稀土磷酸盐，

和一个钇硅酸盐在沉沙现 在商业来源的一些这

些稀有元素。

Separation

of

the

elements

is

a

difficult

chemical

operation.

The

solubilities

of

their

compounds

are

so

nearly

alike

that

a

separation

by

fractional crystallization is laborious and time-consuming. In recent years,

ion exchange resins in high columns have proved effective. When certain

acids

are

allowed

to

flow

down

slowly

through

a

column

containing

a

resin

to

which

ions

of

Group

III

B

metals

are

adsorbed,

ions

are

successively released from the resin

3

. The resulting solution is removed

from the bottom of the column or tower in bands or sections. Successive

sections will contain specific ions in the order of release by the resin. For

example .lanthanum ion (La

3+

) is most tightly held to the resin and is the

last to

be extracted, lutetium ion (Lu

3+

) is less tightly held and appears in

one

of

the

first

sections

removed.

If

the

solutions

are

recycled

and

the

acid concentrations carefully controlled, very effective separations can be

accomplished. Quantities of all the lanthanide series (except promethium,

Pm, which does not exist in nature as a stable isotope) are produced for

the chemical market.

分离的组成部分是一个困难的化工操作。溶解度的化合物是几 乎

一模一样，分离结晶是艰苦和耗时的。近年来，离子交换树脂在高列

< br>已证明有效。

当某些氨基酸可以缓缓流下一列含有树脂的离子组第三

金属离子吸附，先后从

resin3

。由此产生的解 决方案是删除从塔底、

塔带或部分。

连续的部分将包含特定的离 子释放的顺序由树脂。

例如。

镧离子

（

La 3 +

）

是最紧密举行的树脂，

是最后被提取，

镥离子

（

lu3+

）

是不那么严格，

出现在第一部分被删除。

如果溶液再生和酸浓度小心

控制，

可以实现非常有效的分离。

大量的所有镧系元素

（除钷，

下午，

它不存在的性质作为一个稳定的同位素）生 产的化工市场。

The predominant group oxidation number of the lanthanide series is

+3,

but

some

of

the

elements

exhibit

variable

oxidation

states.

Cerium

forms cerium( III )and cerium ( IV ) sulfates, Ce

2

(SO

4

)

3

and Ce(SO

4

)

2

,

which are employed in certain oxidation-reduction titrations. Many rare

earth

compounds

are

colored

and

are

paramagnetic,

presumably

as

a

result of unpaired electrons in the 4

f

orbitals.

主要的氧化数为

+ 3

的稀土系列，但 一些元素表现出不同的氧化态。

铈铈（Ⅲ）形式和铈（Ⅳ）硫酸盐（

SO 4

）

3

，铈和铈（