Portland cement...what is the recipe from scratch?

Question

What is the main ingredient to portland cement and the minor ingredients. What is the base rock that is mined and how high is the heat used to process this rock to a powder for the cement? Before water and aggregate is added what are the other products used. What is the percentage in relation to the base? I hope these questions makes sense.

Answer 1

You are talking about creating cement from limestone.

Manufacturing Process
Portland cement, the fundamental ingredient in concrete, is a calcium silicate cement made with a combination of calcium, silicon, aluminum, and iron. Producing a cement that meets specific chemical and physical specifications requires careful control of the manufacturing process. The first step in the portland cement manufacturing process is obtaining raw materials. Generally, raw materials consisting of combinations of limestone, shells or chalk, and shale, clay, sand, or iron ore are mined from a quarry near the plant. At the quarry, the raw materials are reduced by primary and secondary crushers. Stone is first reduced to 5-inch size (125-mm), then to 3/4-inch(19 mm). Once the raw materials arrive at the cement plant, the materials are proportioned to create a cement with a specific chemical composition. Two different methods, dry and wet, are used to manufacture portland cement. In the dry process, dry raw materials are proportioned, ground to a powder, blended together and fed to the kiln in a dry state. In the wet process, a slurry is formed by adding water to the properly proportioned raw materials. The grinding and blending operations are then completed with the materials in slurry form. After blending, the mixture of raw materials is fed into the upper end of a tilted rotating, cylindrical kiln. The mixture passes through the kiln at a rate controlled by the slope and rotational speed of the kiln. Burning fuel consisting of powdered coal or natural gas is forced into the lower end of the kiln. Inside the kiln, raw materials reach temperatures of 2600�F to 3000�F (1430�C to 1650�C). At 2700�F (1480�C), a series of chemical reactions cause the materials to fuse and create cement clinker-grayish-black pellets, often the size of marbles. Clinker is discharged red-hot from the lower end of the kiln and transferred to various types of coolers to lower the clinker to handling temperatures. Cooled clinker is combined with gypsum and ground into a fine gray powder. The clinker is ground so fine that nearly all of it passes through a No. 200 mesh (75 micron) sieve. This fine gray powder is portland cement.

This should about cover it. Any more questions, see the link below.

Answer 2

The BEST chocolate cake recipe I've used is the Hersey's choco. cake recipe on the back of their unsweetened choc. powder container. It is so moist you don't even need to butter or spray the bakeware prior to baking! The cake slides right out when cooled. As far as the flat & dense problem, try troubleshooting these potiential issues: 1. How old is the baking powder? People rarely use the whole can before it goes stale. Try storing it in the freezer. 2. Warm the eggs to room tempreture before adding to the wet mixture. Very vital for fluffy cakes/baked items. 3. Mix the cake on a very high setting on your mixer. Not egg white high, but from a scale of 1-10 do 7 or 8. This incorporates air which makes it fluffly as well. Do this for at least 3 min. Hope this helps!

Answer 3

Portland cement was developed from cements (or correctly hydraulic limes) made in Britain in the early part of the nineteenth century, and its name is derived from its similarity to Portland stone, a type of building stone that was quarried on the Isle of Portland in Dorset, England. Joseph Aspdin, a British bricklayer, in 1824 was granted a patent for a process of making a cement which he called Portland cement.
The raw materials for Portland cement production are a mixture (as fine dust in the 'Dry process' or in the form of a slurry in the 'Wet process') of minerals containing calcium oxide, silicon oxide, aluminum oxide, ferric oxide, and magnesium oxide.
The raw mixture is heated in a cement kiln, a gigantic slowly rotating and sloped cylinder, with temperatures increasing over the length of the cylinder up to ~1480 °C. and then grinded to powder. When you add water and aggregate to cement you are making a material called concrete.
The water/cement ratio is of paramount importance to the final set strength of the concrete, and the cement/aggregate ratio and aggregate size distribution are also important. I am fairly sure the optimum w/c ratio is 0.28, but up to 0.35 is commonplace. Cement to aggregate ratio depend how strong you want concrete to be.