(April 2015) Corruption in Brazil exists on all levels of society from the top echelons of political power (as seen in the MensalÃ£o Scandal and the Operation Car Wash and the Petrobras scandals) to the smallest municipalities.
Quartz sands, which are high in silica content, are used to make glass. When quartz sands are crushed they produce particles with sharp, angular edges that are sometimes used to make sandpaper for smoothing wood. Some quartz sand is found in the form of sandstone.
It is commonly used in machine molding and hand molding. The sand made can be used to pour liquid metal without drying, which has the advantages of low production cost and short production cycle. Wet clay sand used in sand casting production accounts for about 60%.reen Sand (Clay Sand) Clay sand is the mixture of natural silica sand, clay, additives and water. The clay used to make wet clay sand is bentonite clay. The compressive strength is generally 0.05 to 0.1 Mpa.