4 results about "Calcium chromate" patented technology

The invention discloses a coating liquid for improving compatibility of silicon steel and insulating paint as well as a preparation method and application of the coating liquid, and belongs to the technical field of silicon steel sheet insulating coatings. The coating comprises a stabilizer solution and an insulating solution, the insulating liquid comprises the following raw materials: 1-10% of zinc chromate, 1-10% of magnesium chromate, 1-10% of calcium chromate, 1-5% of glycerol, 1-7% of boric acid, 1-8% of an acrylic emulsion and the balance of water; the stabilizer solution is prepared from the following raw materials in parts by mass: 0.25 to 0.5 part of trisodium citrate, 0.25 to 0.5 part of EDTA (Ethylene Diamine Tetraacetic Acid) disodium and 5.0 to 10.0 parts of water. According to the insulating liquid disclosed by the invention, the ternary chromate is used as an inorganic framework, the acrylic emulsion is used as an organic bridging phase, and the stabilizer is supplemented to form a two-component system, so that the interfacial compatibility between the silicon steel surface and the water-soluble insulating paint is remarkably improved.

The application discloses a method for separating vanadium and chromium elements from vanadium slag, which comprises the following steps: (1) roasting the vanadium slag with sodium carbonate, mixing and roasting the vanadium slag and the sodium carbonate at a certain temperature to convert vanadium and chromium elements in different valence states in the vanadium slag into the highest valence state; (2) low-temperature leaching, leaching the roasting product obtained in the first step with calcium salt and water at low temperature to obtain a calcium chromate crude liquid and a calcium vanadate leaching residue; (3) acid leaching and vanadium precipitation, separating residual chromium in the calcium vanadate leaching residue to obtain a vanadium-containing filter cake; (4) preparing vanadium pentoxide, adding water to the filter cake obtained in the third step, adding NaOH and (NH4)2SO4 to adjust the pH, and then performing water bath heating to obtain polyvanadic acid ammonium precipitate, which is dried and calcined to obtain V2O5 powder; and (5) preparing chromium trioxide, adjusting the pH of the chromium solution obtained in the second step, adding Na2SO3, reducing Cr 6+ to Cr 3+ , combining Cr 3+ with OH ‑ to form Cr(OH)3 precipitate, filtering, and calcining to obtain Cr2O3.

The invention provides a method for recycling electroplating sludge containing copper, nickel, chromium, calcium and iron. The method comprises the following steps: grinding and screening electroplating sludge to obtain sludge powder, mixing carbonate, and then carrying out alkali roasting and water immersion washing to obtain a first solid and a first filtrate; mixing the first solid and chlorine salt, and performing chloridizing roasting and water leaching washing to obtain a second solid and a second filtrate; mixing the second solid and a reducing agent, and then carrying out high-temperature roasting and magnetic separation to obtain iron powder and calcium carbonate; the mixed iron powder and the second filtrate are subjected to a reduction reaction to obtain copper-nickel alloy powder; calcium carbonate and the first filtrate are mixed for a solid-liquid reaction, and a calcium chromate and carbonate solution is obtained. According to the method, the whole process surrounds roasting separation, although the implementation route is slightly long, the whole process is connected in order, selective separation and recovery of different metals are achieved, the recovery rate and the resourceful product quality are high, meanwhile, secondary waste does not exist in the process, retreatment is not needed, and secondary pollution cannot be caused.

The application provides a purification method of a chromium-containing mixed salt, the mixed salt comprising sodium carbonate, sodium bromide and a heavy metal chromium compound, in the method, a high-purity sodium bromide aqueous solution is prepared from the mixed salt and chromium salt is recovered, and the method comprises the following steps: preparing a crude sodium bromide solution, preparing a chromium removal agent by using a barium compound or a calcium compound, removing chromium from the crude sodium bromide solution by using the chromium removal agent and collecting a filtrate A; and treating the filtrate A to obtain a high-purity sodium bromide aqueous solution. In the method, the sodium carbonate in the crude sodium bromide solution is all converted into sodium bromide; by using the method, the chromium in the sodium bromide is removed and converted into barium chromate or calcium chromate products; the obtained sodium bromide no longer contains the heavy metal chromium and can be directly used for preparing high-purity sodium bromide or preparing a sodium bromide aqueous solution.