Just like Google, Bing is featuring a serious anti-spam filtering system that may slow down or completely block any scraping events.
So, if you need Bing for data mining, you need to carefully consider the proxies that you will use for this mission.
As you understand, public and free proxies are not even considered an alternative for that, since they get banned even before you get the first array of data.
Avoiding IP blocks and captchas of Bings require highly reliable proxies that have been properly tested for this search engine and proved to be effective.