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Hydrogen peroxide is a non-volatile aqueous liquid; the bleaching action is primarily carried out by the oxidation of hydrogen peroxide anions (OOH–). Therefore, in hydrogen peroxide-based bleaching, it is important to increase the concentration of OOH– as much as possible in order to reduce unnecessary decomposition of hydrogen peroxide, and precise control of the process parameters is thus crucial. 1. Changes in pulp concentration: Given the relatively low level of pulp and paper production in our country, the use of hydrogen peroxide for bleaching at medium to high concentrations is not yet widespread. It is possible to carry out hydrogen peroxide bleaching on pulp after it has been processed by ordinary thickeners, thereby improving the quality of the pulp. We conducted hydrogen peroxide bleaching on pulp produced by ordinary stone grinders after using multi-disc thickeners; the bleaching concentration was around 5% to 6%. By controlling other process parameters and using 1% to 2% hydrogen peroxide, the brightness of the pulp increased by about 10%, meeting the requirements for producing high-brightness newsprint ； In chemical pulp, we conducted HHP bleaching experiments on natural bamboo pulp in a bleaching machine; at a bleaching concentration of 3% to 4%, the brightness of the pulp reached over 80%. Therefore, as long as the bleaching process parameters are well controlled, low-concentration hydrogen peroxide bleaching can also yield satisfactory results. 2. Pretreatment of pulp before bleaching: Since metal ions such as Fe+, Mn, Cu, and Fe accelerate the ineffective decomposition of hydrogen peroxide, in low-concentration hydrogen peroxide bleaching, the pulp contains a high amount of water and also many metal ions; it is therefore very important to pretreat the pulp using chelating agents, especially in the case of mechanical pulp bleaching. The selection of chelating agents should be determined based on the types and concentrations of metal ions in each factory’s own slurry. It is generally believed that DTPA has an excellent chelating effect on Mn, Fe, and Cu, while sodium tripolyphosphate is effective in chelating Fe. 2%–5% CaCl2 is effective for Mn, and EDTA is less effective than DTPA in dealing with Mn and Cu. The chelating agents work best in alkali-free systems; adding just 0.05% EDTA is sufficient to prevent the decomposition of hydrogen peroxide caused by various metal ions. Therefore, chelating agents should be added in advance, and the type of chelating agent should also vary depending on the location where it is added. 3. Sequence of preparing the chemical solution: The typical sequence for hydrogen peroxide bleaching is to first prepare a mixture of alkali and other auxiliary chemicals such as magnesium sulfate, and then mix this mixture with hydrogen peroxide before adding it to the pulp. Through practice, we adopted a method in which sodium silicate is first added to a dilute solution of magnesium sulfate to form a colloidal suspension of magnesium silicate; then an alkali is added to create a mixture which is combined with the slurry. Finally, concentrated hydrogen peroxide solution is added, so that hydrogen peroxide has an optimal reaction environment from the very beginning of the bleaching process, thereby ensuring high bleaching efficiency. 4. Control of pH value: The pH of hydrogen peroxide ranges from 9 to 13. The higher the pH, the greater the ionization of OOH; however, when the pH exceeds 11, the ineffective decomposition of hydrogen peroxide increases. Experiments have shown that when the pH value is greater than 12, hydrogen peroxide is almost completely decomposed ineffective within 40 minutes. Therefore, in actual production, the pH value during bleaching must be strictly controlled; at the start of bleaching, the pH should be kept between 10.5 and 11, while at the end of the bleaching process, it is advisable to maintain the pH between 9.0 and 9.5. 5. Control of the bleaching endpoint: Low-concentration hydrogen peroxide bleaching should be carried out using high-temperature and rapid bleaching methods. The bleaching endpoint should be determined based on the level of residual hydrogen peroxide and the pH value, and the bleaching process should not take too long.