FAQ >> Metals, cement, and aggregates crusher development

Metals, cement, and aggregates crusher development

Until the 15th century, all the major developments in size reduction were for the food preparation industry-for the grinding of grain to make flour. Although there were demands for minerals, particularly gold, copper, zinc, and lead, and for construction materials, the demands were small, and the methods used to grind grain were adequate. When manually operated tools and machines, however, were applied to crushing and grinding rocks and mineral ores, the size-reduction process took longer because the materials were much harder and required more energy to break. Rocks and mineral ores were also much larger than grains and had to be broken manually before they could even be fed into a mortar and pestle or a quern. Finally, rocks and mineral ores are much more abrasive than grains, increasing the wear and tear on and decreasing the life span of the crushing and grinding equipment.

The increased demand for metals, cement, and aggregates, which began around the 15th century, reached its peak during the 19th and 20th centuries. To meet the increased demand for machinery that could crush and grind metallic and industrial mineral ore, cement raw material and clinker, and large rocks to the smaller size needed for aggre- gates, new classes of heavy-duty equipment using emerging sources of energy were required. As discussed in the last chapter, first waterpower was used with water wheels to drive the machinery. Next came steam engines, which led to further size-reduction developments. Then, electric motors replaced steam engines, reenergizing the progress of size-reduction technology once again. It is interesting to note that water, and the steam made from water, is the main source of energy that drives the turbines that drives the electric generators.

Because rocks, cement raw materials, cement clinker, and mineral ores all require the same basic types of crushing and grinding equipment, we devote this chapter and the two that follow to stamp mills and crushers, roller mills, and tumbling mills. We discuss these technologies roughly in chronological order of their development and also present information on the uses for each.

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