QUES: Zinc metal is produced using extractive metallurgy. After grinding the ore, froth flotation, which selectively separates minerals from gangue by taking advantage of differences in their hydrophobicity, is used to get an ore concentrate. This concentrate consists of about 50% zinc with the rest being sulfur (32%), iron (13%), and SiO
2 (5%). The composition of this is normally zinc sulfide (80% to 85%), iron sulfide (7.0% to 12%), lead sulfide (3.0% to 5.0%) silica (2.5% to 3.5%), and cadmium sulfide (0.35% to 0.41%).

What is froth flotation used for?
What is the answer?
ANS: get an ore concentrate
QUES: The investigation of the transmitted signals started immediately after the launch of Compass -M1 on 14 April 2007. Soon after in June 2007, engineers at CNES reported the spectrum and structure of the signals. A month later, researchers from Stanford University reported the complete decoding of the "I" signals components. The knowledge of the codes allowed a group of engineers at Septentrio to build the COMPASS receiver and report tracking and multipath characteristics of the "I" signals on E2 and E5B.

When did the investigation of the signals transmitted by Compass -M1 begin?
What is the answer?
ANS: immediately after the launch of Compass -M1 on 14 April 2007
QUES: Montana has 56 counties with the United States Census Bureau stating Montana's contains 364 "places", broken down into 129 incorporated places and 235 census-designated places. Incorporated places consist of 52 cities, 75 towns, and two consolidated city-counties. Montana has one city, Billings, with a population over 100,000; and two cities with populations over 50,000, Missoula and Great Falls. These three communities are considered the centers of Montana's three Metropolitan Statistical Areas.

What city in Montana has over 100,000 people?
What is the answer?
ANS:
Billings