Ramisa Sas handles zinc in slabs and semi-finished products.
Commercial zinc has a purity grade of 99.8% with the following impurities: Pb: 0.05 - 0.10%; Fe max. 0.012%; Cd: 0.05 - 0.10%; Cu max. 0.005%; Sn max. 0.001%; Al max. 0.001%.
Zinc slabs known as GOB (Good Ordinary Brand) with various purity grades are also traded on the market, so it is advisable to request the analysis.
Material traded in the exchange warehouses of the London Metal Exchange.
Zinc slabs with 99.995% purity
In slabs, ingots or plates with a maximum weight of 55 kg each.
On the exchange, delivery is allowed only of the brands approved according to the list issued by the London Metal Exchange.
Minimum lot size: 25 TO (each lot must be of a single brand)
ZINC SEMI-FINISHED PRODUCTS
Ramisa can supply:
Zinc wire from 1.2 mm up to 4.74 mm
Zinc wire in ZNAL and ZNSN alloy
Zinc strips with thickness starting from 0.07 mm
Zinc plates machined to drawing
Zinc platelets (100x50x10 mm)
Extruded bars in zinc and alloys:
Bars in pure zinc (20x500 mm)
Bars in pure zinc (40x500 mm)
Pure zinc billet 130 mm diameter x 500 mm length
ZINC SPHERES AND HEMISPHERES FOR ELECTROPLATING AND OTHER PROCESSING
Ramisa can supply:
Zinc spheres
Cylindrical hemispheres 30 x 12/15 mm
Cylindrical hemispheres 33 x 20 mm
Cylindrical hemispheres 33 x 33 mm
Granules
Zinc rods
ZINC ALLOYS - ZAMAK
The term Zamak indicates a group of alloys with a high zinc content, particularly suitable for die casting.
The most common Zamak alloys:
G-ZnAl 14
Zn 96%; Al 4%; Cu 0; Mg 0.03 - 0.06%
G-ZnAl14Cu1
Zn 95%; Al 4%; Cu 1%; Mg 0.03 - 0.06%
G-ZnAlCu3
Zn 93%; Al 4%; Cu 3%; Mg 0.03 - 0.06%
ZINC ANODES FOR CATHODIC PROTECTION
Ramisa supplies zinc anodes and zinc-aluminium anodes for cathodic protection in various shapes and sizes (bars, slabs, bracelet anodes), both for the industrial sector and for the naval and pleasure-boating sector.
Ingot anodes
Bar anodes
Anodes with holes
Zn slabs 190 x 55 x h25 mm
Zn pieces 30 x 30 x 15 mm
Pure Zn plate 500 x 200 x 30 mm
Zn plate 25 x 150 x 300 mm
Zn plate with plastic-coated rope
Zinc platelets with holes
CATHODIC PROTECTION
Cathodic protection is a technique for preventing electrochemical corrosion that is applied to metal structures in contact with environments having electrical conductivity.
It essentially consists in circulating direct current between an electrode, called the anode, and the surface of the structure to be protected, called the cathode. This current lowers the electrical potential of the metal surface until it eliminates corrosive phenomena. The technique of cathodic protection was officially born in England in 1824, established itself in America a century later, and finally throughout the world starting from the 1960s and 1970s. In Italy, cathodic protection was initially applied to protect the lead sheaths of telephone cables, around 1930, and subsequently for the protection of oil pipelines, gas pipelines, aqueducts and structures exposed to corrosion risks.
Application methods of cathodic protection
For a correct application of a cathodic protection system and for cost containment, the coating or painting of the structure to be protected is decisive. For this reason, depending on its size and the environment surrounding it, two systems are applied:
Sacrificial anode system: it does not require electrical energy and simply consists in connecting the surface to be protected to a metal whose electrical potential is less noble. Given the small difference in value between the two metals, driving work, the essential condition is that the electrolyte has a very low resistance value. This condition is always present in sea water, where sacrificial anodes are used very successfully, less so in soils, whose resistivity value, often too high, makes the system ineffective. The metals normally used to protect steel are, in sea water, aluminium and zinc. In soils, magnesium is usually used for its greater driving work;
Impressed current system: the delivery of the protection current takes place through a cathodic power supply, to whose negative pole the structure to be protected is connected and to whose positive pole the anodic groundbed is connected. This system requires electrical energy, but has a considerable driving work that allows its application in soils and to protect structures of considerable size. The benefits provided depend on the current that the system can deliver. The resistance of the circuit is decisive, almost entirely depending on that of the anodic groundbed.
