Can I use the LG Ultrafine 5K display with a PC?
The compatibility of these monitors with a PC and/or Windows is unclear. Even the FAQs page has a couple of related questions, but these are yet to be answered.
However, I wouldn't recommend buying this with the intention of using it with your setup unless you get a definitive answer from either Apple or LG.
In the meantime I refer you to this info:

At this point you may have noticed that all of these specs are the same as Apple's iMacs. LG Display makes the IPS displays in the iMacs, so it's very likely if not certain that these are the same panels. Given that these monitors are targeted at users of the new MacBook Pro, it's also very likely that they do not have any sort of sRGB fallback mode, as such an option is unnecessary on macOS where there is end to end color management in any AppKit app and even in most apps that don't use AppKit. This is important to keep in mind for anyone interested in buying these for a Windows computer. The state of color management on Windows means that in nearly every application you'll be stuck with oversaturated colors and no workaround, so I wouldn't recommend it even if it can work.
While I'm on the topic of Windows support, I will say that from a
technical perspective, the displays should work with a Windows
computer. However, product listings for the monitor specify that you
need a Mac with USB-C for the 4K model, and a Mac with Thunderbolt 3
for the 5K model. This limits the 4K model to Apple's MacBook, and the
new MacBook Pros, with the 5K model only working on the latter. This
also ties back to the integration with macOS. Most monitors use
physical buttons for controlling brightness and volume, but the LG
UltraFine displays use the integrated controls that macOS provides,
meaning that it can respond to the volume and brightness keys on Mac
keyboards. It doesn't look like the monitors have any buttons to fall
back on, so this may be another situation where Windows users should
be wary, and it definitely explains why the monitors are being
marketed specifically for their integration with macOS.

Source: http://www.anandtech.com/show/10798/lg-introduces-new-4k-and-5k-ultrafine-monitors