What happened to the african american soldiers in the north during the civil war?

Some died, some lost their limbs and others survived and lived free for the rest of their lives

Since the answer by pointeman1 covered the main points, I'll cover another area. Although the Civil war was brutal by any standards with higher casualties for Americans than any other war before or since, and life in the military was certainly hard even for white soldiers, let alone blacks, life in the military was a upgrade in living conditions and salary for most of them.

Food and clothing were provided and the pay was better for most of them than any they had previously received. While discipline in the army was harsh, it was certainly no worse than most of them had already experienced.

What no one realized was that the life of an average black man at that time made him ideally suited for soldiering. These men, quite simply put, were already unbelievably tough. And they proved it.

Initially they were looked upon almost the same as the South looked upon their slaves. Few Northerners really thought that Blacks were equals. There were riots in New York City and other Northern cities against a war that would free African-Americans.

The first (serious) Black unit formed was the 54th Massachussetts Volunteers; an infantry regiment. The deal was for the 54th Regiment (and all others) that the officers would be White.

The 54th first major engagement was trying to take Fort Wagner, South Carolina. They suffered over 50% losses as did the attacking White regiments. Fort Wagner was never taken....but...the North now saw the potential in Black units and more were called up and during the Civil War and over 180,000 African-American volunteered. President Lincoln himself credited these Black Union Troops with turning the tide of battle in favor of the Union. Yet when the war was won; when the "Grand Parade" down Pennsylvania Avenue in Washington was on for 4 days, not a single African-American until was invited or allowed to march!

After the war many Black Veterans headed West and became cattle-drovers; and were called "cowboys"

Many remained in the Army. Some were also sent West but, ironically, to surpress the Native-Americans.

They were largely ignored and abandoned by their white masters in the U.S Army. The best example of how they were "used" was at Ft. Pillow, TN. Confederate forces were victorious. During the Union retreat, the Confederates continued to pound the Union forces with military force. The United States attempted to characterize this as a "racial" action by the Confederate forces. In fact, it was more like the Iraqi retreat from Kuwait City, or the German retreat from the Falaise gap. When a military force will not surrender, it is common for the opponent to continue to extract casualties.