Haining Leather Industry Key Technology Is Expected To Break The Bottleneck Of The Industry

Recently, the project "key technology research and integration demonstration of new cycle efficient water saving and clean tannery" carried out by Haining has passed the national expert acceptance group. Three key technologies, such as acid leaching technology, low consumption and high absorption chrome tanning technology and sustainable reuse of waste chrome liquid, have been declared, which are expected to break the bottleneck restricting the development of tannery industry in Zhejiang province.

Haining leather industry as Haining's pillar industry has made outstanding contributions to the local economic construction. However, the environmental pollution of tanning industry is also shocking. Haining tanning industry also has this problem.

In terms of its characteristics, tannery sewage not only produces a large amount of wastewater, but also is a complex and high concentration organic wastewater. It contains a lot of harmful substances such as lime, dyestuff, protein, salt, grease, ammonia nitrogen, sulphide, chromate, and fur and pomace.

At the same time, because of the difference of raw materials (cowhide, sheepskin, pig skin), processing technology and finished leather (shoe upper leather, garment leather, sofa leather, luggage leather, etc.), the water quality of tannery wastewater is very different, which increases the difficulty of governance.

To this end, the Haining municipal government has actively explored new ways, and implemented the project "research and integration demonstration of the key technologies of new circular efficient water-saving and clean tannery".

The project is based on the introduction of the advanced technology of jenis Andy, Spain, and has developed three key technologies, namely, the pickling solution recycling technology, the low consumption high absorption chrome tanning technology, and the recycling of waste chrome solution. These three items are the three common key technologies that restrict the development of leather industry in Zhejiang.

The new technology has designed a set of external circulation system, so that the chromium solution can be treated separately, precipitated and recycled, and can be reused continuously.

The new technology has added a new computer temperature regulation system, a set of drum heating for light skin water field, and a software control setup adjustment procedure, which greatly reduces the water consumption under the premise of ensuring the temperature of the drum in the process requirements. Since it has been used, it can save 60 tons of water and save nearly twenty thousand tons of water throughout the year.

The application shows that the amount of chromium in the traditional chrome tanning method can be reduced by 30%, the absorption rate will be increased to more than 95%, and the chromium emission will be reduced by more than 90%.

"Later, the sludge treatment cost will be greatly reduced, that is to say, the chromium content in the sludge will only account for 5%, and the chrome tanning waste liquid will basically achieve zero emissions."

The second key technological breakthrough is innovation: for the first time, the domestic and foreign tanning industry has concentrated treatment of the wet finishing section wastewater for the first time.

"In the wet finishing section of tanning and retanning, the total water consumption is about 30%, and the water is relatively easy to handle.

In the preparation section of the former Road, soaking and washing wool will not only produce a lot of oil and waste residue, but also a lot of chemical excipients.

The technician told the author that this technology is to concentrate the waste water in the back road and reuse it in the former way. This is a kind of innovation, and has produced good benefits, saving total water consumption up to 35% ~ 40%.

The third key technological breakthroughs lie in the use of enzyme preparation combined with ash and alkali to remove depilation and depilatory paste recycling technology, and reduce the amount of water washing process, as well as the amount of ammonium salt, lime and other substances, and reduce the water consumption of the preparatory section by more than 50%.