Senior U.S. officials involved in indirect talks with Iran returned home yesterday without any prediction of when, or even whether, the time-consuming and tedious process will achieve release of the 52 American hostages.

The U.S. team headed by Deputy Secretary of State Warren Christopher had spent two days in Algiers briefing three Algerian diplomats who are the intermediaries chosen by Iran for the indirect but authoritative contacts.

Christopher said at Andrews Air Force Base that "the process seems to be working." He added, however, "this involves a good deal of time and complexity because we're dealing with three different languages [English, Farsi and the French of the Algerians], different legal systems and some highly complicated financial matters."

Other officials familiar with details of the discussions said Christopher presented the Algerian intermediaries with a 5 1/2-page, double-spaced document presenting the clarifications, requested by Iran, of a five-page U.S. document transmitted through the Algerians three weeks ago.

Sources said U.S. proposals for meeting Iran's four hostage release conditions are still general, with many practical details to be addressed in the indirect dialogue. This suggests that, if this quasi-negotiating process works, it will be many weeks before full agreement can be reached.

Moreover, it is still uncertain whether the faction-ridden authorities in Tehran will agree that the slow process holds sufficient promise to justify continuing. On orders of Ayatollah Ruhollah Khomeni, "negotiation" with the "Great Satan," the United States, has been ruled out, which accounts for the cumbersome indirect procedure.

The official who heads the Iranian end of the diplomatic dialogue, Bhzad Nabavi, minister of state for executive affairs, was quoted in Tehran yesterday as saying the hostages will be freed, stand trial or have their case returned to the Iranian parliament, or Majlis, depending on the latest U.S. message.

"If the response is positive, the release will be done. If negative, we will give the hostages to the court for trial. If the response is halfway, that is, some conditions are accepted and some are not, we will ask the Majlis to tell us what to do," Nabavi was quoted at a news conference in Tehran.

The Iranian official spoke shortly before the arrival in Tehran of the three-man Algerian diplomatic team bearing the message given from Christopher.

Washington officials had no expectation the Iranians would find U.S. response to Iran's conditions completely acceptable, but they hoped Iran would not find it completely unacceptable.

Secretary of State Edmund S. Muskie explained Wednesday that "a literal reading" of the four Iranian conditions is "beyond the president's authority to implement." He said the United States is telling Iran that Carter is able and willing to "go a significant and, indeed, a substantial way toward the objectives" of the Iranian conditions.

Muskie took heart from the fact that Iran and the United States are proceeding through "quiet diplomatic channels" rather than in public, a point reiterated yesterday by State Department officials in explaining their grounds for satisfaction with the current process.

In Tehran, however, Reuter news agency quoted Nabavi as telling the press conference that the U.S. reply will be published "as soon as it reaches Iran."