Responsa sobre Brachot 9:8

Regarding the obligation to recite the blessing on washing the hands every time one exits the toilet and wishes to study Torah or recite the afternoon or evening prayers. For just as in the morning one recites the blessing, so too every time that hand-washing is required, one should recite the blessing.^*There are at least two questions here: whether each of the three daily prayers should be preceded by hand-washing, and whether study of Torah requires ritual hand-washing too. On the first issue, see Rosh on Berachot 9:23 who holds that the blessing on hand-washing should be recited before prayer, but not after going to the toilet otherwise. Rashba reports this issue as a dispute between the Raavad, who required the blessing each time after going to the toilet, and the Ramban, who only required it in the morning (see Teshuvot Hameyuchasot LaRamban 173). See also Tosafot Yeshanim on Yoma 30a:1, where Rabbeinu Tam and his father Rabbeinu Meir hold that handwashing is sometimes required after the toilet, but not a blessing, while others did require it. On the issue of Torah study, see Sefer Mitzvot Katan 181:2, where 'our rabbis' are said to have washed their hands before studying Torah.