In the aluminum surface treatment process, ash removal is a necessary step, and many manufacturers also attach great importance to the ash removal and neutralization process. So, how is the ash on the aluminum surface produced? What are the solutions?

Aluminum alloy ash removal is also known as neutralization or light extraction. The hanging ash mainly comes from the following two processes: 1. Alkaline washing process. After the aluminum alloy is etched by alkali, the alloy elements such as manganese, copper, iron, silicon and their interalloy compounds that are insoluble in the alkaline washing solution will be deposited on the surface, forming a layer of gray-brown or gray-black hanging ash. . 2. Chemical polishing process. The alloy matrix contains heavy metals or in order to improve the polishing effect, a small amount of heavy metal salts (such as copper salts) are usually added to the polishing solution. After these heavy metal ions undergo replacement reaction with aluminum, heavy metal particles are formed and deposited on the surface of the aluminum alloy. The components in the alloy matrix that are insoluble in the polishing solution together form ash. Before the aluminum alloy workpiece enters the oxidation tank, the ash on the surface must be removed in the neutralization tank, otherwise the oxide film will be loosened and the gloss will be dark after coloring.

The traditional ash removal method is to treat nitric acid + hydrofluoric acid at a ratio of 3:1. This process has a high risk factor and large pollution, and is being phased out gradually. At present, the new technology has only emerged in the past three years, and it is also an acidic system. In order to solve this problem, people have gradually developed ash removal reagents that do not contain or slightly contain nitric acid and hydrofluoric acid through multi-method and multi-level research. In this regard, the ht408 chrome-free ash remover of Shenzhen Huashen Jingtai Technology Co., Ltd. has done a good job. It is not only environmentally friendly, but also has a very obvious effect on removing ash and whitening the surface. The other is the sulfuric acid ash removal process, which is also a more traditional ash removal method, but the effect of ash removal is slightly weak, and after the emergence of the new technology, other auxiliary additives are added, which not only achieves the effect of ash removal and whitening, but also does To the purpose of environmental protection ash removal.

In simple terms, most of the ash on the surface is metal ash, which is produced from the aluminum alloy matrix or the chemical polishing agent. There are still many methods of ash removal, but there are certain selectivity. It is recommended to use a new environmentally friendly ash removal process.