Pipe phosphate process

Thermal phosphoric acid process uses yellow phosphorus as raw materials with electrothermal production, made ​​of phosphoric acid with content of 85% by Combustion water.

Thermal phosphoric acid production process with a heat recovery unit, usually two-step method, ie the combustion of phosphorus and P2O5 hydration in the two devices. Among them, P2O5 hydration device with the traditional hydration tower; burning phosphorus equipment within the set of heat exchange tubes, the heat of combustion of the recovery of phosphorus and byproduct steam. The key technology of burning phosphorus devices is how to prevent heat exchange tubes P2O5 was high temperature gas corrosion, and can provide good heat transfer conditions.

The national patent technologies are to be protected by controlling the process conditions, so that the heat exchange steel pipe formed on the surface layer of special phosphide.

Wet process phosphoric acid from phosphate rock inorganic acids (mainly sulfuric acid or hydrochloric acid) decomposition, first obtained the fertilizer with the crude phosphoric acid, and then go through the various steps to purify the impurity, the final purity and thermal process of industrial-grade phosphate concentrate is made . The main purification methods are chemical precipitation, ion exchange resin, crystallization, solvent precipitation and solvent extraction. Solvent extraction has obtained high purity of the product, production technology and equipment is relatively simple, low energy consumption, consumption of raw materials, production capacity, separation, recovery, less environmental pollution, the production process easily automated and continuous, and conducive to the comprehensive utilization of resources and other advantages, which attracted wide attention.

Kiln phosphoric acid process in the rotary kiln using gas heating of low-grade phosphate rock powder, to restore the oxidation reaction, rotary kiln kiln gas preparation of industrial phosphoric acid absorbed by the circulating acid. The new kiln phosphoric acid process is characterized by: high impurity content, it can use low grade phosphate rock to produce high-quality and high concentration of phosphoric acid;, P2O5 content as low as 17% when the high SiO2 content of phosphate in; system the quality and concentration of phosphoric acid at or near the thermal phosphoric acid. In addition, the process to make full use of the chemical reaction heat of the production process, significantly reducing the production of energy.

Phosphating is the process of converting a steel surface to iron phosphate. This is mostly used as a pretreatment method in conjunction with another method of corrosion protection. A layer of phosphate coating typically includes iron, zinc or manganese crystals.

Phosphating is also known as phophatizing and phosphate conversion coating.

Corrosionpedia explains Phosphating
Phosphate coatings are usually applied to carbon steel, low-alloy steel and cast iron. The coating is formed with a solution of iron, zinc or manganese phosphate salts in phosphoric acid, and is applied by either spraying the solution onto the substrate, or immersing the substrate into the solution. When steel or iron parts are placed in the phosphoric acid, this causes a metal reaction which locally depletes the hydronium (H3O+) ions, raises the pH, and causes the dissolved salt to fall out of the solution and precipitate on the surface. The acid and metal reaction also creates iron phosphate, which may be deposited.

The following is a typical phosphating procedure:

The main uses of phosphating are:

Corrosion protection in conjunction with organic coatings, such as paints and polymer films
Facilitation of cold-forming processes, such as wire drawing and tube drawing, or deep drawing

Seamless pipe Specification, standard and identification

Seamless pipes are extensively applied for the nuclear device, gas, petrochemical, ship building and boiler industries. Seamless pipes dominates 65% of market share in Chinese boiler industry.