On the left of the main menu, chose Reference and then Export
Next, choose BibTeX - RefWorks ID from the drop down menu. Be sure to choose "all in list" to capture all references.
The export will create a page like the one below. Save it as a text file from the File menu in your browser.
Next, choose the Import option from the Zotero gear icon:
When you import the saved .txt file from your computer, you citations will be instantly added to a new folder with the name of your text file:
Please note, that when you export your references, it will seem like a long web page of text, but you then simply need to save that file to your computer as .txt, and it can be imported to Zotero.