How to convert minutes to hours using MYSQL?
You need DIV and % operators.

DIV is the integer division and % is the modulo function, returning the reminder:

SELECT 12345 DIV 60 AS hrs, 12345 % 60 as min;


UPDATE

You have to change your query such way:

SELECT
   . . . . .
   TIMESTAMPDIFF(MINUTE, Tickets.date, Tickets.solvedate) DIV 60 AS TempoH,    
   TIMESTAMPDIFF(MINUTE, Tickets.date, Tickets.solvedate) % 60 AS TempoM
   . . . . .