Old Market House (Galena, Illinois) Old Market House (Galena, Illinois) The Old Market House, currently being operated as the Galena Welcome Center, is a brick building built in the Greek Revival style in 1845 in Galena, Illinois. It is owned and operated by the Illinois Historic Preservation Agency as an Illinois State Historic Site. The Old Market House was built by the city of Galena to serve as a city hall and enclosed public farmer's market. A rapid increase in population in the Galena area in the 1830s and 1840s, largely a result of the discovery of galena, a kind of lead ore found in
Mineral processing is not completely known and further research into their mechanisms is being performed. Depressants and activators are used to selectively separate one mineral from another. Depressants inhibit the flotation of one mineral or minerals while activators enable the flotation of others. Examples of these include CN, used to depress all sulfides but galena and this depressant is believed to operate by changing the solubility of chemisorbed and physisorbed collectors on sulfides. This theory originates from Russia. An example of an activator is Cu ions, used for the flotation of sphalerite. There are a number of cells able to be used