In potash it turns black, but in alum nothing happens until you bring it to the boil, then purple colour comes flooding out.
在碳酸钾中，它变成黑色，而在明矾中一开始却什么反应都没有，直到煮沸后紫色都溢出来了。
2
The principle and process of producing potassium-nitrogen compound fertilizer and aluminium hydroxide from potashalum are studied. Some problems are solved through the pilot test.