Method and apparatus for separating valuable minerals from ore

A method for a beneficiation process of minerals, the method comprising the steps of:

• comminuting ore which contains valuable minerals;
• generating an air wall, by an exhaust blower, to the top part of a feed neck comprised by a grinder used for comminution by using a horizontal airflow, via which air access into the grinder is reduced as well as gas and ore dust that have risen to the top part of the feed neck of the grinder are removed;
• performing a classification wherein ore of too large a particle size is returned to the comminuting step, and ore of a desired particle size is directed onwards to a following step of the method, wherein the comminuted ore is beneficiated by flotation for separating valuable minerals;
• feeding, in order to displace oxygen, carbon dioxide oversaturated water and/or carbon dioxide gas to at least one of the following process steps:
• ore comminution, classification of comminuted ore, intermediate step between comminution and classification, feeding of the comminution and/or classification;
• circulating output carbon dioxide from the flotation beneficiation step back to the flotation beneficiation step through a pressure balancing arrangement;
• and
• performing pressure balancing to balance the gas pressure of flotation beneficiation cells used in flotation beneficiation to match the normal ambient air pressure for compensating an effect of a change in a water level of the flotation cells on a volume of gas circulation may be without a need to blow out gas.