How to identify whether there is iron in purified copper sulfate

Determination of iron content in copper sulfate:

1.Reagents: ammonia, ammonium chloride, sulfuric acid, ammonium thiocyanate, isoamyl alcohol, ether, ammonium iron sulfate (ammonium iron-vanadium).

2.Iron standard solution: weigh grams of ammonium iron sulfate, dissolve in 1000 ml of distilled water acidified with 4 ml of concentrated sulfuric acid, take 10 ml, dilute to 100 ml with distilled water. (Prepared for use on the same day).

3.4N ammonium thiocyanate: weigh 304 grams and dilute to 1 liter with distilled water.

4.20% sulfuric acid : weigh 204 grams of sulfuric acid diluted to 1 liter.

5.Determination method: weigh 5 grams of sample (about 2 grams of secondary product) and put it in a 500 ml beaker, add 3 grams of ammonium chloride, and dissolve it in 300 ml of distilled water, add a few drops of nitric acid, nitrate the solution, heat to boil, add excess ammonia to precipitate the iron sludge, and rinse several times with hot distilled water (containing a small amount of ammonia and ammonium chloride).

Dissolve the precipitate on the filter paper in 5 ml of 20% sulfuric acid, place it in a 1000 ml volumetric flask, dilute it to the scale with distilled water, fully invert the solution in the bottle (not shake), mix evenly, aspirate 50 ml of the solution, move it into a 250 ml volumetric flask, dilute it to the scale with distilled water, and mix evenly. Pipette 10 ml into a 50 ml cuvette with grinding plug and add 4 ml of 4 N ammonium thiocyanate solution and 10 ml of isoamyl alcohol (or ether) to mix well. In another cuvette, inject 10 ml of distilled water, 10 ml of 20% sulfuric acid, 4 ml of 4 N ammonium thiocyanate, and 10 ml of isoamyl alcohol (or ether) and drop the iron standard solution with a dropper until the isoamyl alcohol layer of the two tubes is the same color.

Presentation of the results of the analysis.

The mass fraction of iron content in copper sulphate 2 (%) is calculated according to the formula:

2 =v× /(g×50×10 )×100=v/2g

The factors influencing the growth of copper sulfate crystals are as follows.

Effect of solution concentration.

The greater the concentration of the copper sulfate solution, the higher the content of copper sulfate, and the more copper sulfate products crystallized at the same temperature.

Effect of the acidity of the solution.

The more acid in the solution, the finer the crystal particles and the lighter the color. When the amount of acid in the solution is too high, loose and fine scale-like crystals are formed, which are very light in blue and contain a large amount of mother liquor.

Effect of the amount of impurities in the solution.

The more impurities in the solution, the more the crystallization rate of copper sulfate slows down, and the product is impure, the crystal is fine, the color is not correct, and it is mostly green, which does not meet the product standard.

Factors influencing the crystallization state.

Crystals grown at high temperatures are mostly turbid and cracked, while crystals grown at lower temperatures are generally transparent and intact.

Effect of crystallization time on crystallization amount.

The time it takes to crystallize is basically the time it takes for the solution temperature to drop to room temperature. When the temperature of the solution drops to room temperature (or outdoor room temperature), the solid-liquid separation can be carried out by extending the appropriate time slightly. However, due to various factors in production, the time required for the temperature to drop to normal temperature is also different, so the crystallization time is also different.

However, it is best to go through the lowest room temperature (room temperature) during the crystallization process to increase the amount of crystallization. Due to the large amount of natural evaporation in summer, extending the crystallization time will also increase some crystallization.

Hello friends, the purity of copper sulfate after purification is not good, then there will be impurities, it must be that the purification process is relatively backward, can not meet certain accuracy requirements, and the purification equipment is also backward, thank you.

Reactions can occur, but they cannot be said to be precipitation.

If there is too much iron, the precipitated solids are iron and copper, and if there is not enough iron, the precipitated solids are copper.

Iron and copper sulfate solution react to form ferrous sulfate solution and copper, and the precipitate is copper.

Iron reacts with a copper sulfate solution. Red copper is precipitated on the surface of iron. It is a displacement reaction of a single fingertip. This is because? Iron is livelier than copper. It can replace the copper in the copper sulfate solution.

1. The reaction formula of iron and copper sulfate is: Fe+CuSO4=FeSo4+Cu.

2. The phenomenon of the reaction between iron and copper sulfate is: the surface of the iron layer precipitates a red substance, and the solution changes from blue to light green, and finally turns brown.

3. Iron reacts with copper sulfate solution to form ferrous sulfate and copper. Iron is more mobile than copper and can be replaced.

4. Iron is easily soluble in dilute inorganic acids to form divalent iron salts and release hydrogen. When encountering concentrated sulfuric acid or concentrated nitric acid at room temperature, a layer of oxide protective film is formed on the surface to passivate the iron, so iron products can be used to contain cold concentrated sulfuric acid or cold concentrated nitric acid. When heated, iron can react with concentrated sulfuric or concentrated nitric acid to form +3-valent iron salts, along with sulfur dioxide or nitrogen dioxide.

1), take about the product, add 50ml of water, heat to dissolve, take 5ml of solution, add 4 parts of potassium chromate test solution and 1 part of dilute hydrochloric acid mixed solution drops, that is, generate orange flocculent precipitate.

2), take 1ml of the remaining solution under the item (1), add 100ml of water, shake well, add a few drops of tannic acid test solution, and turbidity occurs. (3) Take the product, add sodium lime, heat, that is, ammonia odor. The acidity is taken from the product, added to 100ml of hot water, fully shaken to dissolve, cooled to 35, determined according to law (Appendix H), and the pH value should be .

take the product, put it in an Erlenmeyer flask weighing the weight, add 80ml of water, place it in 15 18 for 2 hours, make the complete Qinghu expand, heat and dissolve it in a 60 water bath, take it out, weigh it, add an appropriate amount of water to make the contents into 100g, take 10ml, put it in a test tube with an inner diameter of 13mm, freeze it in an ice bath for 6 hours, take it out, invert it for 10 seconds, and it should not flow down.

The precipitated composition of the reaction of copper sulphate with iron depends mainly on the ratio of the amount of copper sulphate to the amount of the substance of iron:

When the ratio of the quantities of the two substances is less than or equal to 1:1, the precipitate is copper.

When the ratio of the quantities of the two substances is greater than 1:1, the precipitate is copper and iron.

The reaction equation between copper sulfate and iron is: CuSO4+FE=Cu+FeSO4, and the reaction principle is displacement reaction, that is, the active metal replaces the inactive metal, which is also a redox reaction. It should be noted that FE becomes +2 instead of +3, and the reflected copper will adhere to iron, so iron powder should be used.

Copper or copper and iron (depending on the amount of iron.)

Of course, whoever is hard and who is powerful has the sulfuric acid.

For copper sulphate solution.

To extract copper directly, in addition to the active metal reduction method, an electrolytic method can be used, so that the metallic copper is deposited directly on the cathode.

If the thermal reduction method is used, it must be converted into a solid, which is basically an oxide first, and then a reducing agent.

Thermal reduction. The use of C as a reducing agent is not ideal, because it is a solid and the surface contact is too poor, while H2 and CO are both gases, which is a reducing agent that does not miss mistakes.

After a while, the iron is placed in a copper sulfate solution, and the surface of the iron is covered with a layer of copper powder.

The copper sulfate solution becomes a pale green sulfur cavity, which is rotten acid resistant to ferrous iron.

Solution. Chemical prescription for leakage.

fe+cuso4=feso4+cu

Dissolve them separately in water, the light green is Feso4 and the blue is Cuso4

First, use hydrogen peroxide.

Oxidation of ferrous ions to iron ions.

Then, the wheel adds copper oxide to react with hydrogen ions, which promotes the hydrolysis of iron ions to produce hydrogen-preferred iron oxide.

precipitation, and then filter out the iron hydroxide and the remaining copper oxide to obtain a copper sulfate solution.

The principle is: the degree of hydrolysis of Huidan ferric iron ions is large, and it can be removed by promoting its hydrolysis, and copper oxide (or copper hydroxide) is added.

No new impurities are introduced. However, at the beginning, ferrous ions need to be oxidized to iron ions.