how do they use salt to make ice in fish factories?

Answer 1

Because salt water freezes at a temperature well below pure water, salt water can be chilled to below 32F and circulated to a cooler that produces ice. The same method is used to freeze and maintain skating rinks cold. There are a series of brine filled pipes circulating cold salt water just under the surface of the fresh water ice. If you add salt to cracked pure-water ice, it will decrease the temperature of the mixture (almost to 0F) and this was the method used in the old fashioned hand cranked ice cream makers that almost every home used to have. By the time you cranked out a batch of ice cream on a very hot day you were more than ready to eat it.

Answer 2

because salty water is denser than fresh water. that's why ships easily float in the ocean. this 'denser' water freezes, but its freezing point is below 0. not like fresh water. there fore, if it freezes slow. it will melt slow. they use it to save ice. if they will use fresh water ice, it won't last.