Joseph Aspdin was an English cement manufacturer who obtained the patent for Portland cement on 21 October 1824.
Joseph Aspdin (or Aspden) was the eldest of the six children of Thomas Aspdin, a bricklayer living in the Hunslet district of Leeds, Yorkshire.
By 1817 he had set up in business on his own in central Leeds. He must have experimented with cement manufacture during the next few years, because on 21 October 1824 he was granted the British Patent BP 5022 entitled An Improvement in the Mode of Producing an Artificial Stone, in which he coined the term "Portland cement" by analogy with the Portland stone, an oolitic limestone that is quarried on the channel coast of England, on the Isle of Portland in Dorset.
Aspdin called the product Portland cement because set mortar made from it resembled “the best Portland stone". Portland stone was the most prestigious building stone in use in England at the time. The patent clearly does not describe the product recognised as Portland cement today.
The product was aimed at the market for stuccos and architectural pre-cast mouldings, for which a fast-setting, low-strength cement was required (see cement). It was fired at low temperature (below 1250 °C) and therefore contained no alite.
The process described is a "double burning" process in which the limestone is burned on its own first, then slaked, mixed with clay, and burned again. This was a common practice for manufacturers of both Artificial and Portland cements when only hard limestones were available.
The grinding technology of the time consisted only of flat millstones, and it was more economic to comminute the limestone by burning and slaking than by grinding.
According to edubilla.com