The present invention relates to a method for production of calcium compounds having very low content of phosphorus and boron from an impure calcium chloride, solution containing phosphorus and boron, which method comprises the following steps: a) addition of a FeCl3-solution to the calcium chloride solution, b) adjusting the pH of the solution by addition of a base to between 3 and 9.5 for precipitation of iron hydroxide, iron phosphate and boron compounds, c) removal of the solid precipitate from the solution in step b) obtaining a purified calcium chloride solution, d) precipitation of a calcium compound from the solution from step c), and e) separation of the calcium compound from the solution in step d).