aparece às vezes e eu perco meu 4G e vá direto para isso e não tenho conexão, como faço para me livrar dele?
It shows up sometimes and I lose my 4g and go straight to that and have no connection, how do I get rid of it?
It's "1x" not "1k".
This is the core fallback 2G cellular connection of a CMDA (Verizon in the US) network. It's not showing up to replace your 4G LTE connection, it's your LTE that is failing and 1x is the only signal that can reach your phone.
The same thing happens with any carrier and it is by design. If you are in an area that is at the edge of their premium 4G service, you fallback to 3G then 2G.
See Wikipedia page on CDMA for more details.
This is regarding your connection strength. For example, if you are on a GSM network and are in a low coverage area, you could have 4G (HSPA+) or E (EDGE) network connectivity. There is not a way to get rid of it other than changing your provider for service, which is probably Sprint, or by constantly turning airplane mode on for a moment and turning it back off to refresh the connection to your cellular service.