Environmental Progress in the Aluminum Industry in the United States

 Environmental Progress in the Aluminum Industry in the United States

Pollution prevention initiatives have been recognized

For better environmental performance due to waste reduction. The focus is on reducing air emissions,

Discharge of water, and solid waste. primary plants are

equipped to capture pollutants and recycle raw materials, and industrial furnaces are continuously reducing

The amount of chlorine gas used.

Recycling aluminum is very important because

Economic as well as environmental impact

on the product. the amount of aluminum that has been

Recycling has doubled in the last decade. Recycling Saves

About 95 percent of the energy is required to extract aluminum from its parent bauxite ore. due to approx

About two-thirds of the aluminum beverage cans produced are recycled at 10,000 recycling centers nationwide and environmental concerns.

Types of Aluminum

aluminum

The four-digit number system is used to identify the pure

Aluminum and Wrought Aluminum Alloys, Table 3-24.

The first digit indicates the major alloying group. For example, IXXX identifies an aluminum that is at least 99.00. is

percent net; 2XXX is aluminum with copper

Major alloying element.

three categories of aluminum

Most welding applications are commercially pure aluminum, wrought aluminum alloys, and aluminum castings

alloy

• Commercially Pure Wrought Aluminum (1100) 99 . is

Percentage of pure aluminum with little iron and silicon

added. It is easily welded, and the weld has strength

Equivalent to the material being welded.

• Wrought aluminum-manganese alloy (3003) includes

About 1.2 percent manganese and a minimum of 97 percent aluminum. It is stronger than the 1100 types and is

less ductile. This reduces his working capacity. it can be welded

without difficulty, and the welds are strong.

• aluminum-silicon-magnesium-chromium alloy (6151)

It has silicon and magnesium as its main alloys. weld

is not as strong as the material being welded, but the weld

The strength can be improved by heat treatment.

• aluminum-magnesium-chromium alloy (5052) is

Strong and highly resistant to corrosion. good flexibility

Allows the material to work. Cold work will produce hardness.

• aluminum-magnesium-silicon alloy (6053) is readily

Can be welded and heat treated.

in titanium-making

United States of America

Titanium is a versatile metal due to its lightweight,

physical properties and mechanical properties. Titanium

Mineral concentrates arise mainly from heavy mineral sands containing ilmenite and/or rutile and

Also, titaniferous slag is formed by the smelting of ilmenite with carbon. These minerals are sand and titaniferous

Slag is processed by pigment manufacturers

The United States of America. However, the United States has become

increasingly dependent on imports of titanium mineral

concentrates.

Titanium dioxide, as ilmenite or exocrine ore,

Usually associated with iron. this material can be

Rutile is one of its purest forms and was mined from beach sand.

Titanium dioxide in the manufacture of pigment

The main raw materials are rutile and ilmenite. It is estimated that about a third of the world's supply of titanium dioxide pigment is found in the United States.

state. In fact, the United States has 362,000. exports to

tons in a typical year.

Titanium sponge is produced in vapor retort by

Phase reduction of titanium tetrachloride with magnesium (Krol process) or sodium (Hunter process)

Metal. (Titanium sponge got its name because of

Spongelike appearance at this point of processing.)

The crawl process is the most common method used

For sponge production around the world.

Titanium ingot is formed by melting of sponge,

Scrap, or a combination of both. alloying elements such as

As vanadium and aluminum are combined to produce

Specific properties are required in the finished product.

Russia and the United States make up the bulk of the production

The world supply of ingots. Vacuum Arc Remelt (VAR)

The process is used to refine the material. a vacuum melter

As shown in Figure 3-20, pages 57-58. In this figure a steel

The electrode is shown, however when refining titanium, a titanium electrode will be used.

Titanium mill products are manufactured by rolling, forging, drawing, or extruding slabs and ingots into products such as billets, bars, rods, wires, plates, sheets, pipes, bars, etc.

and tube. Titanium can also be cast in a variety of

Product.

Scrap and waste are produced at each stage of the production process as well as the manufacturing process. Titanium scrap is a great source of feedstock material

Increase in the melting efficiency of the cold hearth. Above

Two-thirds of the titanium scrap consumed is from a new material that has never been put into service.

Titanium has several properties that make its replacement with other materials very difficult.