Do you need to pay tax on used instrument recycling

No need.

According to the Circular of the Ministry of Finance and State Administration of Taxation on the Policy of Value-added Tax on Renewable Resources, since January 1, 2009, the sales of waste materials by business units engaged in the recycling of waste materials are exempted from value-added tax, and other units and individuals should pay value-added tax on the sales of waste materials according to law. If you meet the provisions of the Circular of the Ministry of Finance and State Administration of Taxation on the Policy of Value-added Tax on Renewable Resources, you don't need to pay the value-added tax.