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How It's Made - Inorganic Pigments

people have always used color as a means

of expression prehistoric man created

paint from a mix of dirt and animal fat

or spit over the centuries pigment

production has become a lot more

sophisticated chemical manufacturing

produces synthetic mineral pigments to

add color to the products in our world

from pavers to paint to plastic and

cosmetics this is where the color comes

from synthetic mineral pigments they

start with a salt recycled from the

steel industry in this case it's iron

sulfate which has a bluish green hue

they add warm water and they're ready

for the next ingredient high-quality

scrap it's another source of iron and

it's about to be recycled into pigment

crane claws transfer it to the mix

chemicals are added

every so often a technician scrutinizes

a sample of the yellow slurry if he

decides the color or thickness aren't

quite right adjustments will be made the

slurry now flows over a perforated metal

drum with a filter cloth stretched

across it as a spray of water rinses off

the salt the fluid in the yellow slurry

is sucked through the filter cloth and

into the drum leaving a more

concentrated pigment on the surface

called filter cake the filter cake falls

and chunks onto a screw conveyor and

ends up at the top of a towering spray

dryer inside Machinery presses the

highly concentrated pigment through the

holes of a rotating disc this causes a

spray of droplets that when exposed to

hot air dries into pigment particles

this yellow pigment is now ready to be

mixed into an emulsion paint for

coloring wallpaper a generous amount can

produce a bolder shade a little less and

it's a more mellow yellow to make black

pigment they start with cast iron

filings another form of automotive scrap

this magnetic crane transfers the

filings for production and again it will

take a chemical reaction to produce the

pigment slurry the chemical reaction

also generates energy that's recovered

and used in the manufacturing process

they wash and thicken the black slurry

on a revolving drum just like they did

for the yellow pigment but this thick

paste won't just be used to make black

pigment it will also be used to make red

for the dramatic conversion to red the

paste flows directly into a kiln where

it's baked until dry they introduce air

and increase the temperature to 850

degrees Celsius making the black

particle turn red they transfer the red

pigment to a drum where they mix the

pigment and adjust the color properties

then they grind it to a finer

consistency once the pigment is packaged

in paper bags it's ready for transport

or warehousing

like sugar pigment comes in both a

powdered and granulated form this

demonstration shows the difference

between the two the powdered pigment is

more clumpy and doesn't flow from the

opened end of the beaker

by contrast the granular pigments are

tiny microbeads that flow freely which

makes it desirable for users who want to

mix and meter pigments more easily to

test how the pigment would color brick

they mix red pigment with a concrete

substitute and compare the result to the

standard to confirm that they match up

but sometimes they need a real concrete

example of a pigments color tone so they

add a small amount to a mixer full of

aggregate water and cement the mixer

rotates and once the ingredients are

thoroughly blended they open the lid to

reveal the red brick paste they scoop it

up for transfer to a brick forming

machine

and then Philbrick forms with the paste

they activate a plunger that taps it

down to compact it into the forms

producing bricks red black or yellow

these pigments are sure to make things

more colorful