The use of a water-miscible polyhydric alcohol (component B) having two or three hydroxyl groups for improving the collector performance of a collector composition for the reverse iron ore flotation (component A) comprising at least one alkyl ether amine of formula and/or alkyl ether diamine of formula R 1 -(O-A)-NH 2 R 2 -(O-A)-NH-R 3 -NH 2 wherein R 1 is a hydrocarbyl group with 6 to 24 carbon atoms, R 2 is a hydrocarbyl group with 6 to 24 carbon atoms, R 3 is an aliphatic hydrocarbyl group with 2 to 4 carbon atoms A is an alkylene group with 2 to 6 carbon atoms, wherein the water- miscible polyhydric alcohol (component B) having two or three hydroxyl groups is selected from the group consisting of ethylene glycol propylene glycol, butylene glycol, pentanediol, neopentyl glycol, hexanediol, glycerol, diethylene glycol and triethylene glycol, wherein the term "improving the collector performance" means (i) an increase of recovery rate of iron ore when the water-miscible polyhydric alcohol having two or three hydroxyl groups is present, compared to the case when said alcohol is absent; (ii) a higher selectivity in removal of silicate, which means that the collector composition comprising the water-miscible polyhydric alcohol enables a higher proportion of the iron to be retained and a higher proportion of the silicate to be removed, compared to the case when said alcohol is absent; (iii) that the amount of iron retained and the amount of silicate removed in the flotation process according to the second aspect in the presence of the water-miscible polyhydric alcohol remains essentially unchanged when the temperature at which said process is executed drops to temperatures of below 10 °C, preferably down to 5 °C, or even below 5 °C, compared to the case when said alcohol is absent in which case the amount of iron retained and the silicate removed becomes poorer; (iv) that the froth formed by the collector composition comprising the water-miscible polyhydric alcohol is less voluminous, and after separation from the flotation cell it collapses faster, compared to the case when said alcohol is absent, and wherein improvement of collector performance and improving the collector performance is assumed to occur if one or more of conditions (i) to (iv) are met. R 1 is a hydrocarbyl group with 6 to 24 carbon atoms, R 2 is a hydrocarbyl group with 6 to 24 carbon atoms, R 3 is an aliphatic hydrocarbyl group with 2 to 4 carbon atoms A is an alkylene group with 2 to 6 carbon atoms, wherein the water- miscible polyhydric alcohol (component B) having two or three hydroxyl groups is selected from the group consisting of ethylene glycol propylene glycol, butylene glycol, pentanediol, neopentyl glycol, hexanediol, glycerol, diethylene glycol and triethylene glycol, wherein the term "improving the collector performance" means (i) an increase of recovery rate of iron ore when the water-miscible polyhydric alcohol having two or three hydroxyl groups is present, compared to the case when said alcohol is absent; (ii) a higher selectivity in removal of silicate, which means that the collector composition comprising the water-miscible polyhydric alcohol enables a higher proportion of the iron to be retained and a higher proportion of the silicate to be removed, compared to the case when said alcohol is absent; (iii) that the amount of iron retained and the amount of silicate removed in the flotation process according to the second aspect in the presence of the water-miscible polyhydric alcohol remains essentially unchanged when the temperature at which said process is executed drops to temperatures of below 10 °C, preferably down to 5 °C, or even below 5 °C, compared to the case when said alcohol is absent in which case the amount of iron retained and the silicate removed becomes poorer; (iv) that the froth formed by the collector composition comprising the water-miscible polyhydric alcohol is less voluminous, and after separation from the flotation cell it collapses faster, compared to the case when said alcohol is absent, and wherein (i) an increase of recovery rate of iron ore when the water-miscible polyhydric alcohol having two or three hydroxyl groups is present, compared to the case when said alcohol is absent; (ii) a higher selectivity in removal of silicate, which means that the collector composition comprising the water-miscible polyhydric alcohol enables a higher proportion of the iron to be retained and a higher proportion of the silicate to be removed, compared to the case when said alcohol is absent; (iii) that the amount of iron retained and the amount of silicate removed in the flotation process according to the second aspect in the presence of the water-miscible polyhydric alcohol remains essentially unchanged when the temperature at which said process is executed drops to temperatures of below 10 °C, preferably down to 5 °C, or even below 5 °C, compared to the case when said alcohol is absent in which case the amount of iron retained and the silicate removed becomes poorer; (iv) that the froth formed by the collector composition comprising the water-miscible polyhydric alcohol is less voluminous, and after separation from the flotation cell it collapses faster, compared to the case when said alcohol is absent, and wherein improvement of collector performance and improving the collector performance is assumed to occur if one or more of conditions (i) to (iv) are met.