(2) Preparation example
① The main components of zinc ore powder produced by direct acid hydrolysis of zinc ore powder react with hydrochloric acid , and the reaction is as follows:
The zinc chloride generated by the above reaction enters the solution, and the silicon element becomes a gel in the form of orthosilicic acid, which affects the filtration.
②The hydrochloric acid directly decomposes the zincite to produce zinc chloride
The main component of smithsonite is ZnCO 3 , and the following reactions occur when it is leached with hydrochloric acid:
ZnCO 4 +2HCl→ZnCl 2 +H 2 O+CO 2 ↑
The process flow of preparing zinc chloride from smithsonite is shown in Figure 6-16
Figure 6-16 The process flow of preparing industrial zinc chloride from smithsonite
Fe, Cu, Pb, Cd, Ca, Mg, etc.
Place the suction filter funnel on another suction filter flask, wash the filter residue with 90℃ hot water, dissolve the lead chloride in the residue in the hot water, wash several times (washing solution is about 1500mL), add hydrochloric acid to the filtrate to adjust the solution The pH is about 1
③ NH 4 Cl leaching zincite to produce zinc chloride NH 4 CI has the property of dissolving ZnO.
④ Production of zinc chloride with zinc sulfide as raw material.
In addition to adding a roasting process to convert zinc sulfide into zinc oxide, the roasting method is basically the same as the traditional production method, except that a small amount of zinc sulfide is contained in the raw material during the leaching process.
In the direct method, a large amount of hydrogen sulfide is produced by the reaction, the leaching equipment must be sealed and the tail gas must be completely absorbed by the lye before it can be vented
⑤The production process of preparing zinc chloride by using by-product zinc hydroxide to prepare zinc chloride from by-product zinc hydroxide includes four steps of water washing, compounding, purification, and concentration
Concentration: Adjust the acidity of the purified filtrate and transfer it to the reactor to evaporate.
After concentrating to above 50°Be, transfer it to a large basin to continue evaporation and concentration
During the evaporation process, if any abnormal phenomenon is found in the solution, potassium chlorate or hydrazine hydrochloride can be added to treat the solution until the solution is clear and transparent without variegation
When the liquid temperature reaches 260-270℃, after the bubbles become smaller, the product is discharged out of the basin, cooled, and crushed to obtain the finished product of zinc chloride
[Technical index] HG/T2323-2004 industrial zinc chloride
Related link: Preparation method of zinc chloride