The most stable monolayer boron phase, known as α-borophene, has exceptional potential for use in flexible spintronics due to its remarkable stiffness. Moreover, it is a promising choice for thermoelectric applications due to its low thermal conductivity and high carrier mobility compared to graphene. Using nonequilibrium Green's function (NEGF) combined with the tight-binding (TB) Hamiltonian methods, we investigate thermal spin-dependent currents and the spin Seebeck effects of a zigzag αborophene nanoribbon (α-BNR) in a ferromagnetic-normal-ferromagnetic (FM/NM/FM) junction. Our results show that a pure spin current can be created by an appropriate temperature gradient, which arises from the asymmetrical electrons and holes in α-BNR. This phenomenon is accompanied by the emergence of Seebeck thermopowers with opposite directions for up and down spins, which induces a pure thermal spin voltage in this system. Thermal spin and charge currents behave like a thermoelectric diode in low temperatures. Also, the system can provide perfect spin filtering. To evaluate the spin-dependent thermoelectric efficiency, the spin figure of merit and spin power factor are calculated. It is found that the spin figure of merit can be effectively enhanced as the exchange field strength in leads increases. In addition, we show that the spin figure of merit depends on the width of the nanoribbon and increases as the width of the nanoribbon decreases. Our findings suggest that α-BNR is a favorable material for spinthermoelectric devices.