Ferric Chloride Etching
Product origin :Tangshan City, Hebei Province, China
Delivery time :15-30 days
Supply capacity :400,000 tons/ year
Ferric chloride made by 3R are strictly controlled in raw materials and production process, which guarantees the high quality, safety and stable performance of the products, and is well received by customers. Ferric chloride is popular and mainly used in water treatment including waste water treatment and drinking water treatment,sludge dehydration and pcb etching,etc.
The Chemistry of Ferric Chloride
Since Rembrandt , etchers have used nitric acid and Dutch mordant to etch copper. At th eturn of the century ferric chloride solution was introduced in gravure work principally because of its interaction with gum bichromate gelatine. With the increased emphasis on health and safety at work, we have had to reappraise these and other chemicals we use. The salt, ferric chloride, has none of the disadvantages associated with the other two etching solutions: it does not produce dangerous fumes, is odourless and, though corrosive, is not absorbed through the skin. Ferric chloride solutions in water are strongly acidic but in their reaction with copper no significant fumes or gases are produced. Simply, except in the presence of free oxygen, copper will not react to any significant extent with hydrochloric acid which is the acid produced with ferric chloride solutions. When ferric chloride is dissolved in water the solution becomes strongly acidic as a result of hydrolysis. The chemical reaction, in words and formulae are:
basically, ferric chloride in water solution ionizes to iron (ferric) and chloride ions; whilst the water ionizes to hydrogen and hydroxyl ions;
Fe³ + 3CL
H³ + OH
The ferric ions will partially combine with the hydrogen and hydroxyl ions to form ferric hydroxide, a compound which is only slightly soluble and precipitates from solution as a brown solid.
Fe³ + 3OH
This precipitation can be regarded as removing hydroxyl ions from the solution, leaving a relative excess of hydrogen ions and it is this access of hydrogen ions that makes the solution acidic. Because of a property of metals known as electro- negativity, copper replaces iron from the solution and forms a mixture of ferrous and cupric irons. Effectively this copper dissolves without producing any gas;