dry mixer/blender

[alee72]

We are currently using an ordinary concrete mixer to blend a mixture sodium sulphate (95%) and some other chemicals (5%)in a humid environment.

Problem we encounter is rusting and corrosion of the mixer. The rust also contaminates the mixture.

Now we are considering to build our own mixer, what material is suitable to build the mixer? Our mechanical department is suggesting using stainless steel. From memory they are various type of stainless steel, should i find one with high chromium content? Is it possible to coat the stainless steel with some material to avoid rusting and contamination?

Any other tips on shape of mixer and motor selection will be appreciated.

 

[me7snake]

what material is the concrete mixer made of? if its just iron, have you tried attaching a sacrificial anode (Mg/Zn).

 

[JimCasey]

Used mixers are readily available.

304 stailess steel is common (also called 18-8 stainless)
Many types of mixers exist, but dual-cone mixers are extremely simple with no internal moving parts.

There are a lot of details involved in making your mixer perform to your expectations. Buying a proven design will get you up and running more quickly, and you will have an immediately consistent product.

Scan google for used dual-cone mixers. Here is one site:

http://www.aaronequipment.com/UsedEquipment/Mixers/Double+Cone+-+V+Mixers.html#

 

[alee72]

we had acceptable mixing result with the old concrete mixer, just that it's a bit small and prone to corrosion.

we intend to build a new one similar to the old one but scale it up a bit to make a bigger batch size.

we have been reading up on stainless steel i feel SS316L/SS034L will be suitable of this operation? However the weldment of baffles inside the mixer will be most prone to corrosion.

@me7snake: it's possible to use a sacrificial anode or impressed current cathodic protection in this situation? I thought the use of such system is only for eqpt/structure submerged in water or underground, such as underwater/underground pipeline? Will it work for a mixer in a plant?