Neal's link on efflorescence is probably correct and if so indicated moisture is evaporating through that spot and leaving the minerals behind. But the problem may be bigger than that crust you see.
i see a hose to a floor drain that may be increasing the amount of water under that slab. I would suggest that be discharges into the sewer drain or pumped outside. But unknown is what other water issues there might be, do you have a sump pit?
Resolve the moisture under the concrete and then repair that spot. Also notes is that the floor appears to be painted or otherwise partially sealed making that spot the easiest point of exit. Sealing everything may just push the moisture out somewhere else.
Bud
i see a hose to a floor drain that may be increasing the amount of water under that slab. I would suggest that be discharges into the sewer drain or pumped outside. But unknown is what other water issues there might be, do you have a sump pit?
Resolve the moisture under the concrete and then repair that spot. Also notes is that the floor appears to be painted or otherwise partially sealed making that spot the easiest point of exit. Sealing everything may just push the moisture out somewhere else.
Bud