
Concept explainers
Given the abundance of aluminum in the Earth’s crust, explain why it is more expensive than steel.

Given the abundance of aluminum in the Earth’s crust, explain why it is more expensive than steel
Explanation of Solution
Aluminum, being an abundant metallic element, makes up about 8% of the Earth’s crust.
Bauxite serves as the principal ore for aluminum, and is a hydrous (water-containing) aluminum oxide containing various other oxides.
At first, clay and dirt is washed off from the ore. Then the ore is crushed into powder and treated with hot caustic soda (sodium hydroxide) to remove the remaining impurities. Next, extraction of alumina (aluminum oxide) takes place from this solution which is dissolved in a molten sodium-fluoride and aluminum-fluoride bath at a temperature of about 940◦ to 980◦C (1725◦ to 1800◦F).
Then, direct-current electrolysis of this mixture is performed. Aluminum metal is formed at the cathode (negative pole), and oxygen is gathered at the anode (positive pole). Commercially, 99.99% pure aluminum can be obtained. Aluminum production consumes a lot of electricity which affects its cost in comparison to steel.
Want to see more full solutions like this?
Chapter 6 Solutions
Manufacturing Engineering & Technology
- PROBLEM 3.46 The solid cylindrical rod BC of length L = 600 mm is attached to the rigid lever AB of length a = 380 mm and to the support at C. When a 500 N force P is applied at A, design specifications require that the displacement of A not exceed 25 mm when a 500 N force P is applied at A For the material indicated determine the required diameter of the rod. Aluminium: Tall = 65 MPa, G = 27 GPa. Aarrow_forwardFind the equivalent mass of the rocker arm assembly with respect to the x coordinate. k₁ mi m2 k₁arrow_forward2. Figure below shows a U-tube manometer open at both ends and containing a column of liquid mercury of length l and specific weight y. Considering a small displacement x of the manometer meniscus from its equilibrium position (or datum), determine the equivalent spring constant associated with the restoring force. Datum Area, Aarrow_forward
- 1. The consequences of a head-on collision of two automobiles can be studied by considering the impact of the automobile on a barrier, as shown in figure below. Construct a mathematical model (i.e., draw the diagram) by considering the masses of the automobile body, engine, transmission, and suspension and the elasticity of the bumpers, radiator, sheet metal body, driveline, and engine mounts.arrow_forward3.) 15.40 – Collar B moves up at constant velocity vB = 1.5 m/s. Rod AB has length = 1.2 m. The incline is at angle = 25°. Compute an expression for the angular velocity of rod AB, ė and the velocity of end A of the rod (✓✓) as a function of v₂,1,0,0. Then compute numerical answers for ȧ & y_ with 0 = 50°.arrow_forward2.) 15.12 The assembly shown consists of the straight rod ABC which passes through and is welded to the grectangular plate DEFH. The assembly rotates about the axis AC with a constant angular velocity of 9 rad/s. Knowing that the motion when viewed from C is counterclockwise, determine the velocity and acceleration of corner F.arrow_forward
- Welding: Principles and Applications (MindTap Cou...Mechanical EngineeringISBN:9781305494695Author:Larry JeffusPublisher:Cengage Learning
