In quartz sand pickling equipment, it is crucial to choose
corrosion-resistant materials due to the strong corrosiveness of the acidic
media used, such as hydrochloric acid, hydrofluoric acid, etc. Here are some
specific suggestions:
1. Understand the process conditions
Types and concentrations of acids: Different acids (such as hydrochloric
acid, sulfuric acid, hydrofluoric acid, etc.) have different corrosive effects
on materials, and the higher the concentration, the stricter the requirements
for equipment materials.
Working temperature and pressure: High temperature or high pressure
conditions can accelerate corrosion reactions, so corrosion-resistant materials
that can maintain stability under the operating conditions should be
selected.
2. Suggestions for commonly used corrosion-resistant materials
(1) Highly corrosion-resistant plastics and polymer materials
PTFE (polytetrafluoroethylene): It has excellent chemical corrosion
resistance and is suitable for most strong acid environments. It is the
preferred material for lining and sealing of pickling equipment. The
disadvantage is low mechanical strength and high price.
PFA (perfluoroalkoxy ethylene copolymer): Similar to PTFE, but with better
processability, suitable for manufacturing components such as pipelines, valves,
and reactor liners.
PVDF (polyvinylidene fluoride): With good corrosion resistance and high
mechanical strength, it is suitable for producing components in low
concentration acid washing systems.
Polypropylene (PP) and polyvinyl chloride (PVC): For some acid washing
processes with low corrosiveness, PP or PVC can be used, but their corrosion
resistance is poor in high concentration or high temperature acid washing.
(2) Corrosion resistant metal materials
Corrosion resistant stainless steel (such as 316L): 316L stainless steel
performs well in many acidic environments, but may not be suitable for special
acidic media such as hydrofluoric acid.
Titanium and titanium alloys: Titanium has excellent corrosion resistance and
is suitable for extreme acidic environments (such as hydrofluoric acid), but the
cost is high and it is suitable for critical parts or extremely demanding
working conditions.
Nickel based alloys, such as Inconel series alloys, also have strong
corrosion resistance, but are relatively expensive and are usually used for
components under extreme conditions.
3. Selection of key components for equipment
Reaction tank lining: It is recommended to use PTFE or PFA lining, which have
excellent corrosion resistance in strong acid environments and can protect the
metal body from direct contact with acid solution.
Pipes and valves: PVDF or PTFE pipes and valves can be selected based on the
concentration and temperature of the acid; For high demand environments,
titanium pipes and valves can be used.
Sealing element: Use FKM or other acid resistant sealing materials to ensure
stable sealing performance.
4. Comprehensive cost and performance balance
Cost effectiveness consideration: When choosing materials, it is important to
balance corrosion resistance and cost. For example, for less demanding pickling
conditions, 316L stainless steel with polymer lining can be used; For highly
corrosive environments (such as high concentration hydrofluoric acid), it may be
necessary to use a full set of titanium or high-performance polymers.
Long term durability: Although some corrosion-resistant materials (such as
titanium and PTFE) have higher initial costs, considering long-term operation
and maintenance costs, using these materials can significantly extend the
service life of equipment, reduce replacement frequency and downtime.
5. Suggested measures
Experimental verification: Before formal selection, it is recommended to
conduct small-scale experiments under actual working conditions to verify the
corrosion resistance of the selected materials.
Regular testing and maintenance: Even if corrosion-resistant materials are
selected, it is necessary to establish a regular testing and maintenance system
to promptly identify potential corrosion issues and ensure long-term stable
operation of the equipment.
Supplier selection: Choose suppliers with good reputation and technical
support to ensure that the corrosion-resistant materials provided meet relevant
standards and can provide comprehensive after-sales service.
summarize
For quartz sand pickling equipment, the selection of corrosion-resistant
materials needs to comprehensively consider factors such as the type,
concentration, temperature, and pressure of the acid solution used. Common
corrosion-resistant materials include highly corrosion-resistant plastics such
as PTFE, PFA, PVDF, as well as corrosion-resistant metals such as 316L stainless
steel, titanium, and titanium alloys. By selecting materials for key components
of the equipment reasonably, and combining experimental verification, regular
testing, and maintenance, the stability and durability of the equipment in acid
pickling process can be significantly improved, while reducing long-term
operating costs.