Pulp and Paper Mill Chemicals Received: Caustic - Sodium Hydroxide - Used to make cooking liquor in chemical and some mechanical pulp mills.  Also used in recycle mills to reprocess the pulp.  Received as 50% solution in dedicated chemical tank cars.  Usually comes in the manufacturers cars, like Olin or Hooker, or lessor cars like GATX.  They say sodium hydroxide on the side near the end. Lime - Calcium Carbonate - Used to make cooking liquor in chemical pulp mills.  Received in about any style of 2 or 3 bay covered hopper, usually with lime streaks down the side, unless they're brand new. Sulfuric Acid - Used to acidify the pulp in any pulp or paper mill.   Used for pH adjustment in waste treatment plants.  Received as 93 or 97% solution in dedicated chemical tank cars.  Usually comes in the manufacturers cars, like Olin or Hooker, or lessor cars like GATX.   They say sulfuric acid on the side near the end. Salt Cake - Sodium Sulfate -  Used to make cooking liquor in chemical pulp mills. Received in railroad name covered hoppers. Chlorine - Used in chemical pulp mills with bleach plants (white paper.)  Received as liquefied gas in dedicated tank cars.  Usually comes in the manufacturers cars, like Olin or Hooker, or lessor cars like GATX.  They say chlorine on the side near the end. It has been phased out in the 1980's and early 1990's. Sodium Chlorate - Used in chemical pulp mills with bleach plants (white paper.) Used to make chlorine dioxide, a bleach.  This bleach has replaced chlorine, and is too unstable to ship, so you buy the chlorate crystal and make it on site. It comes in a special covered hopper that is lined or made of aluminum.  Instead of hoppers with doors on the bottom, the hoppers are sealed with pipe connections on the side.  You pump hot water into the car to dissolve the crystal.   You could make one from a cylindrical or centerflo hopper by cutting it down to 2 bays.  The aluminum ones are not painted, so they look silver.  It has only been used since the mid 1950's. Sulfur Dioxide - Used in chemical pulp mills with bleach plants (white paper.) Received as liquefied gas in dedicated tank cars.   Usually comes in the manufacturers cars, like Olin or Hooker, or lessor cars like GATX.  They say sulfur dioxide on the side near the end. Starch - Used in paper mills for sizing (water resistance) and coatings.  Received as powder in a covered hopper, often the airslide type, or as a slurry in a chemical type tank car.  Usually comes in the manufacturers car, like Corn Products (CPC) or Staley.  The slurry wasn't around before the 1980's.   In the old days it came bagged or loose in boxcars. Clay - Kaolin - Used in paper mills to fill (make smoother) or coat the paper.  .  Received as powder in a covered hopper, often the airslide type, or as a slurry in a chemical type tank car.  Usually comes in the railroad cars, like Sandersville (almost all the clay in the US comes from this Georgia railroad,) or the manufacturer's car, like Thiele.  Its been largely phased out since the 1980's, in favor of calcium carbonate.  The slurry wasn't around before the 1980's.   In the old days it came bagged or loose in boxcars. Calcium Carbonate -  Used in paper mills to fill (make smoother) or coat the paper.  .  Received as powder in a covered hopper, often the airslide type, or as a slurry in a chemical type tank car.  Mills with a pulp mill usually make it on site.  Its brighter and cheaper than clay.  It wasn't used too much before the 1980's. Talc  -  Used in paper mills to fill (make smoother) or coat the paper.  Also used in pulp mills as additive to control pitch.   Received as powder in a covered hopper, often the airslide type.  Its not that common a filler, and for a pulp mill it usually comes in bags rather than a full car. Muriatic Acid - Hydrochloric Acid - Used to acidify the pulp in any pulp or paper mill.  Used for pH adjustment in waste treatment plants.  Received as 37% solution in dedicated chemical tank cars.   Usually comes in the manufacturers cars, like Olin or Hooker, or lessor cars like GATX.  They say hydrochloric or muriatic acid on the side near the end.  Its not nearly as common as sulfuric, since its more expensive. Soda Ash - Used to make cooking liquor in chemical and some mechanical pulp mills.  Received in railroad name covered hoppers.   Its not nearly as common as caustic. Peroxide - Hydrogen Peroxide - A bleach used in chemical, mechanical, and recycle mills - Usually received as 50% solution by truck, but if far away from the manufacturer, it comes in 70% solution in short tanks (the little 30 footers).  It wasn't used much before the 1980's Methanol -  Used in manufacturing chlorine dioxide.  Usually received by truck, but does come by tank car.  It wasn't used before the 1980's. Shipped: Tall Oil - Chemical pulp mills generate a product called tall oil.   It is a byproduct from making pine pulp.  It is shipped out in chemical tank cars.  This is much more common in the south. Turpentine - Again a byproduct from southern pine mills.  It is not very heavy, so if you have always wanted one of those 60 foot tank cars, they are used for turpentine (the regular ones too.)