Question

600 tons of low grade iron ore (40% Fe) are blended with 400 tons of high grade iron ore (65% Fe). The grade of the blended ore is ........ % Fe (answer in one decimal place).

Hint:

To calculate the grade of a blended ore, use the weighted average of the constituent ore grades based on their mass and percentage content.

Answer 1

Correct Answer: 50

Step 1: Understand the blending process.
We are given the mass of low grade and high grade iron ore, along with their respective Fe percentages. To calculate the grade of the blended ore, we use a weighted average formula.

Step 2: Calculate the total amount of Fe in each ore.
For the low grade ore (600 tons, 40% Fe): \[ \text{Fe in low grade ore} = 600 \, \text{tons} \times 0.40 = 240 \, \text{tons of Fe} \] For the high grade ore (400 tons, 65% Fe): \[ \text{Fe in high grade ore} = 400 \, \text{tons} \times 0.65 = 260 \, \text{tons of Fe} \]

Step 3: Calculate the total amount of Fe in the blended ore.
\[ \text{Total Fe in blended ore} = 240 \, \text{tons} + 260 \, \text{tons} = 500 \, \text{tons of Fe} \]

Step 4: Calculate the grade of the blended ore.
The total mass of the blended ore is: \[ \text{Total mass of blended ore} = 600 \, \text{tons} + 400 \, \text{tons} = 1000 \, \text{tons} \] The grade of the blended ore is: \[ \text{Grade of blended ore} = \frac{500 \, \text{tons of Fe}}{1000 \, \text{tons of ore}} \times 100 = 50.0% \, \text{Fe} \]

Step 5: Conclusion.
The grade of the blended ore is 50.0% Fe.