There are a number of requirements you need to fulfill in order to get a student visa in Argentina. Having you high school diploma validated is just one of them.
I found this on an official .gov.ar website (translated by google):
If you finished your secondary education in a country with which Argentina does not have an educational agreement and want to study at a higher level in a national institution, you have to carry out the recognition process.
What documentation do I need?
First, they must be sent to the educational authority of the jurisdiction where they reside to take the National Training courses (RM No. 2202/13). Once approved, you must begin the process of recognition in the Directorate of National Validity of Titles (RM No. 1208/05).
Identity accreditation document (original and photocopy).
Foreign:
In the case of not having DNI, they must present identity document with the one that entered the country (passport or identity card as the case may be).
Important:
In all cases the documentation that proves the identity of the interested party must be valid.
The school documentation must correspond to the completion of secondary education that allows the pursuit of higher education in the country of origin.
The surname (s) or the name (s) must be exactly the same between all the school documents and those of the current identity document.
School documentation (original and photocopy).
Analytical (or its equivalent according to the country that issues the school documentation).
Title (or its equivalent according to the country that issues the school documentation).
Proof of approval of the National Training subjects, legalized by:
Ministry of Education of the jurisdiction where he gave the National Formation subjects.
Legalization circuit:
All foreign school documentation must contain the following legalizations:
Ministry of Education of the country of origin that certifies the signature of the school authority.
Ministry of Foreign Affairs of the country of origin that certifies the signature of the Ministry of Education.
Argentine consulate in the country of origin that certifies the signature of the Ministry of Foreign Affairs.
Or, in case of coming from countries that are adhered to the Apostille Convention of the Hague, the intervention of the Argentine Consulate is not necessary.
Translation of the documentation written in foreign language:
Documentation written in a foreign language must be translated in Argentina, by a Public Translator of Registry and legalized before the Translators' Association corresponding to each jurisdiction.
Source:
https://www.argentina.gob.ar/reconocer-titulo-secundario-de-paises-sin-convenio
I then found this information using google, searching for the requirements to study in Argentina:
Note: This is not an .gov.ar website so the information should be compared to the requirements listed on the Argentine migraciones website.
Case 3. International students from Countries that DO REQUIRE A VISA to enter Argentina as tourists
They must request their application for admission to an Argentine University in their country of origin and that university will request the National Migrations Office to issue an authorization to enable students’ entry.
With their authorization to enter the country and a university admission, students will request their visa at the Argentine Consulate in their country, which they will receive provided they fulfil the following requirement:
•Prove their identity by means of a valid passport;
•Lack of a criminal record in their country of origin or where they have resided during the past five (5) years;
•Submit birth certificate;
•Prove financial means to subsist and stay in Argentina;
•Prove necessary knowledge of the national language
•Take notice that their entrance has been granted for the sole purpose of attending the courses which are the reason for requesting residence;
•Pay respective fee.
Having fulfilled these procedures, a temporary residence permit shall be granted for a period of two years in all cases, which may be extended as long as they maintain the lack of a criminal record in Argentina, their regular student status and pay the specific fee.
Source:
http://estudiarenargentina.siu.edu.ar/aplicacion.php?ah=4f5889ae57820&ai=estudiar||19000030&mapa_grande=¬icia=&id_idioma=3&contacto=&institucion_universitaria=&mapa_del_sitio=&declaracion_legal=&id_menu=22#Case3
