You can remove they from your toolbar, use the option customize to do this:

• Customize Firefox controls, buttons and toolbars

You can toggle the loop.enabled pref to false on the about:config page. Close and restart Firefox.

You can open the about:config page via the location/address bar. You can accept the warning and click "I'll be careful" to continue.

• http://kb.mozillazine.org/about:config

Right-click each of those buttons and select Remove from Toolbar.

That's alright but i want to deploy the Firefox to some Workstation in our Company and i don't want that they have the possibility to "share" pages.

regarding the share-functionality, you could lock social.share.activationPanelEnabled and social.remote-install.enabled to false and social.activeProviders to an empty string...

http://kb.mozillazine.org/Locking_preferences