Spiral steel pipe machine for the manufacture of spiral seam welded pipe, It can produce the same diameter of pipe with different width of coil. Or It can produce the different diameter of pipe with different width of coil.
The process: uncoiler - leveler - shear welding station - disc trimmer - Milling Machine - delivery machine - pre-bent guide device - machine - both inside and outside welding equipment - sizing device - line ultrasonic testing equipment - rear axle and pipe cutting devices --- X-ray detection device - flat head chamfering machine - hydraulic press - welding station - weighing measuring - corrosion equipment - spray-standard equipment.
Rolling Machine is the key equipment of spiral pipe production, which is using a three-roll Bending Machine principle of continuous metal strip rolled into a spiral tube, and then single-sided welding, double-sided welding or high frequency welding spiral steel made.
Spiral Welded Tube Machine,Spiral Welded Pipe Mill,High Frequency Welding Tube Mill Zhongtuo Roll Forming Machinery Co., ltd , https://www.frameforming.nl
3I 2 +6Na0H ==== NaI0 3 +5NaI+3H 2 0
When the iodine is excessive, a sodium iodate-sodium iodide-water system is formed. Excess iodine and a large amount of iodide ions in the system form stable polyiodide ions, and the following dynamic balance exists:
I 2 +I - +H 2 0; â†â†’ I 3 - ·H 2 0
3I 2 +I - +H 2 0 â†â†’ I 7 - ·H 2 O
The dissolution reaction of gold is based on the oxidation of polyiodide ions to form complex salts of Au(I) and Au(III):
2Au+I 3 - +I - ====2[AuI 2 ] -
2Au+I 7 - +I - ====2[AuI 4 ] -
The iodate in the system acts as an auxiliary oxidation during the dissolution of gold.
The gold dissolved in the system can be extracted by activated carbon adsorption, organic solvent extraction, metal replacement, reducing agent reduction, ion exchanger enrichment and the like. From the viewpoint of simplicity and economy, the use of zinc, iron or substituted saturated sodium sulfite powder can obtain a high recovery rate reduction, reduction reaction as follows:
2[AuI 2 ] - +Zn - ==== [ZnI 3 ] - +I - +2Au ↓
3[AuI 2 ] - +Fe - ====[FeI 4 ] - +2I - +3Au ↓
2[AuI 2 ] - +SO 3 2- +H 2 0 ==== SO 4 2- + 4I - +2H + +2Au ↓
Consider the recovery and reuse of iodine, reduce the recovery of gold impurities in iodine, and use sodium sulfite to reduce it. The iodine in the system after the recovery of gold can also be regenerated according to the fact that in the acidic solution of sulfuric acid, iodine ions are oxidized by potassium chlorate to precipitate iodine:
6I - +C10 3 - +6H + ==== 3I 2 +Cl - +3H 2 0
The principle of recovery of gold by iodination
I 2 -NaI-H 2 O system. When iodine is dissolved in NaOH, the following reactions occur: