Abstract: Disclosed are a lens structure, a photographic device and a focusing method of lens. The lens structure includes a lens barrel, a lens assembly, a drive mechanism, a position detection device and a control device. The lens barrel is extended along a first direction. The lens assembly includes a lens group configured to be movable along the first direction. The drive mechanism is fixedly connected to the lens group and configured to drive the lens group to move along the first direction. The position detection device configured to detect a position of the lens group in real time. The control device is electrically connected to the position detection device and the drive mechanism, and is configured to control the drive mechanism to work according to the position detection device to adjust the position of the lens group.

Abstract: A method of preparing ferric phosphate from iron-containing waste, including: step a) providing a ferric chloride-containing mixture solution obtained from acidolysis of iron-containing waste; step b) adjusting pH of the ferric chloride-containing mixture solution to satisfy 0<pH?2 and Fe3+ concentration to 10-80 g/L with an alkaline compound and water, to obtain an iron source solution; step c) mixing and reacting the iron source solution obtained from the step b) with a solution of calcium dihydrogen phosphate in a molar ratio of P to Fe of 1 : 1-1.8, to obtain a slurry with a pH of 0.2-2; and step d) performing aging and crystal transformation on the slurry, to obtain ferric phosphate. A battery-grade ferric phosphate with high purity and good product quality can be obtained without the need for deep purification of raw materials.