Blackish-Green solution

I was bored and feeling stupid tonight, so I dropped a 9v battery in salt water, hoping to make NaOH. It seemed to work at first, as bubbles of hydrogen were rapidly being formed. But then, I checked back on it a few minutes later, and something blackish was drifting around. Bubbles were still forming (at the anode only, for some reason), so I decanted the solution into a new container. The solution has blackish particles drifting around in a dark green solution. My guess is that the manganese dioxide and potassium hydoxide reacted in solution to make the green solution of potassium manganate, and extra manganese dioxide would explain the black particles. Is this logical, and if not, why? What was the solution? And how did it act the way it did (did the sodium hydroxide eat through the battery?) Now, I know this was in hindsight a dumb experiment, but I'm curious as to what the result was.