Consequences of Charging a Non-Rechargeable Battery
You should never attempt to charge a battery unless you are absolutely certain that it is a rechargeable battery. Non-rechargeable batteries contain dangerous chemicals which can escape if placed in a battery charger.
A non-rechargeable battery, or primary cell, will overheat if placed in a battery charger. Even a normal rechargeable battery will increase slightly in temperature when charged, as will the charging mechanism. When the non-rechargeable battery overheats the seals will break, causing the battery to leak or explode. If the battery explodes the chemicals will spread all over the immediate area, which is a serious health hazard. In extreme cases, the battery may burst into flames. If the heat does not affect the battery enough to open the seal, nothing happens, but the battery will most likely be useless afterward.
How Non-Rechargeable Batteries Work
The reason for these extreme reactions is that non-rechargeable batteries contain chemicals that create a surplus of electrons. Once these chemicals are exhausted, the charge is exhausted, and the battery is dead. A rechargeable battery contains a different set of chemicals that can store excess electrons which can be replenished using an electrical charge. Over time, however, even a rechargeable battery will lose its ability to store these excess electrons and will no longer be able to contain a charge. When one tries to charge a non-rechargeable battery using electricity they are acting against both the physical shell of the battery and the chemical processes contained within.